If global_ops function is being called directly, instead of the global_ops
list function, set the global_ops private to be the same as the ops private
that's being called directly.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently the tracers (function, function_graph, irqsoff, etc) can only
be used by the top level tracing directory (not for instances).
This sets up the infrastructure to allow instances to be able to
run a separate tracer apart from the what the top level tracing is
doing.
As tracers need to adapt for being used by instances, the tracers
must flag if they can be used by instances or not. Currently only the
'nop' tracer can be used by all instances.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
As options (flags) may affect instances instead of being global
the flag_changed() callbacks need to receive the trace_array descriptor
of the instance they will be modifying.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
As options (flags) may affect instances instead of being global
the set_flag() callbacks need to receive the trace_array descriptor
of the instance they will be modifying.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Each sub-buffer (buffer page) has a full 64 bit timestamp. The events on
that page use a 27 bit delta against that timestamp in order to save on
bits written to the ring buffer. If the time between events is larger than
what the 27 bits can hold, a "time extend" event is added to hold the
entire 64 bit timestamp again and the events after that hold a delta from
that timestamp.
As a "time extend" is always paired with an event, it is logical to just
allocate the event with the time extend, to make things a bit more efficient.
Unfortunately, when the pairing code was written, it removed the "delta = 0"
from the first commit on a page, causing the events on the page to be
slightly skewed.
Fixes: 69d1b839f7 "ring-buffer: Bind time extend and data events together"
Cc: stable@vger.kernel.org # 2.6.37+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Pull core block IO changes from Jens Axboe:
"The major piece in here is the immutable bio_ve series from Kent, the
rest is fairly minor. It was supposed to go in last round, but
various issues pushed it to this release instead. The pull request
contains:
- Various smaller blk-mq fixes from different folks. Nothing major
here, just minor fixes and cleanups.
- Fix for a memory leak in the error path in the block ioctl code
from Christian Engelmayer.
- Header export fix from CaiZhiyong.
- Finally the immutable biovec changes from Kent Overstreet. This
enables some nice future work on making arbitrarily sized bios
possible, and splitting more efficient. Related fixes to immutable
bio_vecs:
- dm-cache immutable fixup from Mike Snitzer.
- btrfs immutable fixup from Muthu Kumar.
- bio-integrity fix from Nic Bellinger, which is also going to stable"
* 'for-3.14/core' of git://git.kernel.dk/linux-block: (44 commits)
xtensa: fixup simdisk driver to work with immutable bio_vecs
block/blk-mq-cpu.c: use hotcpu_notifier()
blk-mq: for_each_* macro correctness
block: Fix memory leak in rw_copy_check_uvector() handling
bio-integrity: Fix bio_integrity_verify segment start bug
block: remove unrelated header files and export symbol
blk-mq: uses page->list incorrectly
blk-mq: use __smp_call_function_single directly
btrfs: fix missing increment of bi_remaining
Revert "block: Warn and free bio if bi_end_io is not set"
block: Warn and free bio if bi_end_io is not set
blk-mq: fix initializing request's start time
block: blk-mq: don't export blk_mq_free_queue()
block: blk-mq: make blk_sync_queue support mq
block: blk-mq: support draining mq queue
dm cache: increment bi_remaining when bi_end_io is restored
block: fixup for generic bio chaining
block: Really silence spurious compiler warnings
block: Silence spurious compiler warnings
block: Kill bio_pair_split()
...
the new features added to 3.14.
The third patch is a minor bugfix to the trace_puts() functions that
will crash the system if a developer adds one before the tracing system
is setup. It also affects trace_printk() if it has no arguments, as
the code will convert it to a trace_puts() as well. Note, this bug
will not affect unmodified kernels, as trace_printk() and trace_puts()
should only be used by developers for testing.
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Merge tag 'trace-fixes-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"The first two patches fix the debugfs README file to reflect better
the new features added to 3.14.
The third patch is a minor bugfix to the trace_puts() functions that
will crash the system if a developer adds one before the tracing
system is setup. It also affects trace_printk() if it has no
arguments, as the code will convert it to a trace_puts() as well.
Note, this bug will not affect unmodified kernels, as trace_printk()
and trace_puts() should only be used by developers for testing"
* tag 'trace-fixes-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Check if tracing is enabled in trace_puts()
tracing: Fix formatting of trace README file
tracing/README: Add event file usage to tracing mini-HOWTO
If trace_puts() is used very early in boot up, it can crash the machine
if it is called before the ring buffer is allocated. If a trace_printk()
is used with no arguments, then it will be converted into a trace_puts()
and suffer the same fate.
Cc: stable@vger.kernel.org # 3.10+
Fixes: 09ae72348e "tracing: Add trace_puts() for even faster trace_printk() tracing"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Fix the formatting of the README file in the trace debugfs to fit in
an 80 character window.
Also add a comment about the event trigger counter with regards to
traceon and traceoff.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
It would be useful to have a cheat-sheet for everything under
tracing/events/ alongside the existing text describing the other files
in the tracing/ dir.
Add short descriptions of the directories and files under events/
along with examples, similar to the existing text for the other files
in tracing/.
Also clean up a few minor alignment problems noticed when adding the
new text.
Link: http://lkml.kernel.org/r/1389993104.3040.445.camel@empanada
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
triggers by Tom Zanussi. A trigger is a way to enable an action when an
event is hit. The actions are:
o trace on/off - enable or disable tracing
o snapshot - save the current trace buffer in the snapshot
o stacktrace - dump the current stack trace to the ringbuffer
o enable/disable events - enable or disable another event
Namhyung Kim added updates to the tracing uprobes code. Having the
uprobes add support for fetch methods.
The rest are various bug fixes with the new code, and minor ones for
the old code.
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Merge tag 'trace-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"This pull request has a new feature to ftrace, namely the trace event
triggers by Tom Zanussi. A trigger is a way to enable an action when
an event is hit. The actions are:
o trace on/off - enable or disable tracing
o snapshot - save the current trace buffer in the snapshot
o stacktrace - dump the current stack trace to the ringbuffer
o enable/disable events - enable or disable another event
Namhyung Kim added updates to the tracing uprobes code. Having the
uprobes add support for fetch methods.
The rest are various bug fixes with the new code, and minor ones for
the old code"
* tag 'trace-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (38 commits)
tracing: Fix buggered tee(2) on tracing_pipe
tracing: Have trace buffer point back to trace_array
ftrace: Fix synchronization location disabling and freeing ftrace_ops
ftrace: Have function graph only trace based on global_ops filters
ftrace: Synchronize setting function_trace_op with ftrace_trace_function
tracing: Show available event triggers when no trigger is set
tracing: Consolidate event trigger code
tracing: Fix counter for traceon/off event triggers
tracing: Remove double-underscore naming in syscall trigger invocations
tracing/kprobes: Add trace event trigger invocations
tracing/probes: Fix build break on !CONFIG_KPROBE_EVENT
tracing/uprobes: Add @+file_offset fetch method
uprobes: Allocate ->utask before handler_chain() for tracing handlers
tracing/uprobes: Add support for full argument access methods
tracing/uprobes: Fetch args before reserving a ring buffer
tracing/uprobes: Pass 'is_return' to traceprobe_parse_probe_arg()
tracing/probes: Implement 'memory' fetch method for uprobes
tracing/probes: Add fetch{,_size} member into deref fetch method
tracing/probes: Move 'symbol' fetch method to kprobes
tracing/probes: Implement 'stack' fetch method for uprobes
...
In kernel/trace/trace.c we have this:
static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
__free_page(buf->page);
}
static const struct pipe_buf_operations tracing_pipe_buf_ops = {
.can_merge = 0,
.map = generic_pipe_buf_map,
.unmap = generic_pipe_buf_unmap,
.confirm = generic_pipe_buf_confirm,
.release = tracing_pipe_buf_release,
.steal = generic_pipe_buf_steal,
.get = generic_pipe_buf_get,
};
with
void generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
{
page_cache_get(buf->page);
}
and I don't see anything that would've prevented tee(2) called on the pipe
that got stuff spliced into it from that sucker. ->ops->get() will be
called, then buf gets copied into target pipe's ->bufs[] and eventually
readers get to both copies of the buffer. With
get_page(page)
look at that page
__free_page(page)
look at that page
__free_page(page)
which is not a good thing, to put it mildly. AFAICS, that ought to use
the normal generic_pipe_buf_release() (aka page_cache_release(buf->page)),
shouldn't it?
[
SDR - As trace_pipe just allocates the page with alloc_page(GFP_KERNEL),
and doesn't do anything special with it (no LRU logic). The __free_page()
should be fine, as it wont actually free a page with reference count.
Maybe there's a chance to leak memory? Anyway, This change is at a minimum
good for being symmetric with generic_pipe_buf_get, it is fine to add.
]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[ SDR - Removed no longer used tracing_pipe_buf_release ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The trace buffer has a descriptor pointer that goes back to the trace
array. But it was never assigned. Luckily, nothing uses it (yet), but
it will in the future.
Although nothing currently uses this, if any of the new features get
backported to older kernels, and because this is such a simple change,
I'm marking it for stable too.
Cc: stable@vger.kernel.org # v3.10+
Fixes: 12883efb67 "tracing: Consolidate max_tr into main trace_array structure"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The synchronization needed after ftrace_ops are unregistered must happen
after the callback is disabled from becing called by functions.
The current location happens after the function is being removed from the
internal lists, but not after the function callbacks were disabled, leaving
the functions susceptible of being called after their callbacks are freed.
This affects perf and any externel users of function tracing (LTTng and
SystemTap).
Cc: stable@vger.kernel.org # 3.0+
Fixes: cdbe61bfe7 "ftrace: Allow dynamically allocated function tracers"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Doing some different tests, I discovered that function graph tracing, when
filtered via the set_ftrace_filter and set_ftrace_notrace files, does
not always keep with them if another function ftrace_ops is registered
to trace functions.
The reason is that function graph just happens to trace all functions
that the function tracer enables. When there was only one user of
function tracing, the function graph tracer did not need to worry about
being called by functions that it did not want to trace. But now that there
are other users, this becomes a problem.
For example, one just needs to do the following:
# cd /sys/kernel/debug/tracing
# echo schedule > set_ftrace_filter
# echo function_graph > current_tracer
# cat trace
[..]
0) | schedule() {
------------------------------------------
0) <idle>-0 => rcu_pre-7
------------------------------------------
0) ! 2980.314 us | }
0) | schedule() {
------------------------------------------
0) rcu_pre-7 => <idle>-0
------------------------------------------
0) + 20.701 us | }
# echo 1 > /proc/sys/kernel/stack_tracer_enabled
# cat trace
[..]
1) + 20.825 us | }
1) + 21.651 us | }
1) + 30.924 us | } /* SyS_ioctl */
1) | do_page_fault() {
1) | __do_page_fault() {
1) 0.274 us | down_read_trylock();
1) 0.098 us | find_vma();
1) | handle_mm_fault() {
1) | _raw_spin_lock() {
1) 0.102 us | preempt_count_add();
1) 0.097 us | do_raw_spin_lock();
1) 2.173 us | }
1) | do_wp_page() {
1) 0.079 us | vm_normal_page();
1) 0.086 us | reuse_swap_page();
1) 0.076 us | page_move_anon_rmap();
1) | unlock_page() {
1) 0.082 us | page_waitqueue();
1) 0.086 us | __wake_up_bit();
1) 1.801 us | }
1) 0.075 us | ptep_set_access_flags();
1) | _raw_spin_unlock() {
1) 0.098 us | do_raw_spin_unlock();
1) 0.105 us | preempt_count_sub();
1) 1.884 us | }
1) 9.149 us | }
1) + 13.083 us | }
1) 0.146 us | up_read();
When the stack tracer was enabled, it enabled all functions to be traced, which
now the function graph tracer also traces. This is a side effect that should
not occur.
To fix this a test is added when the function tracing is changed, as well as when
the graph tracer is enabled, to see if anything other than the ftrace global_ops
function tracer is enabled. If so, then the graph tracer calls a test trampoline
that will look at the function that is being traced and compare it with the
filters defined by the global_ops.
As an optimization, if there's no other function tracers registered, or if
the only registered function tracers also use the global ops, the function
graph infrastructure will call the registered function graph callback directly
and not go through the test trampoline.
Cc: stable@vger.kernel.org # 3.3+
Fixes: d2d45c7a03 "tracing: Have stack_tracer use a separate list of functions"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Some method to deal with rt-mutexes and make sched_dl interact with
the current PI-coded is needed, raising all but trivial issues, that
needs (according to us) to be solved with some restructuring of
the pi-code (i.e., going toward a proxy execution-ish implementation).
This is under development, in the meanwhile, as a temporary solution,
what this commits does is:
- ensure a pi-lock owner with waiters is never throttled down. Instead,
when it runs out of runtime, it immediately gets replenished and it's
deadline is postponed;
- the scheduling parameters (relative deadline and default runtime)
used for that replenishments --during the whole period it holds the
pi-lock-- are the ones of the waiting task with earliest deadline.
Acting this way, we provide some kind of boosting to the lock-owner,
still by using the existing (actually, slightly modified by the previous
commit) pi-architecture.
We would stress the fact that this is only a surely needed, all but
clean solution to the problem. In the end it's only a way to re-start
discussion within the community. So, as always, comments, ideas, rants,
etc.. are welcome! :-)
Signed-off-by: Dario Faggioli <raistlin@linux.it>
Signed-off-by: Juri Lelli <juri.lelli@gmail.com>
[ Added !RT_MUTEXES build fix. ]
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1383831828-15501-11-git-send-email-juri.lelli@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It is very likely that systems that wants/needs to use the new
SCHED_DEADLINE policy also want to have the scheduling latency of
the -deadline tasks under control.
For this reason a new version of the scheduling wakeup latency,
called "wakeup_dl", is introduced.
As a consequence of applying this patch there will be three wakeup
latency tracer:
* "wakeup", that deals with all tasks in the system;
* "wakeup_rt", that deals with -rt and -deadline tasks only;
* "wakeup_dl", that deals with -deadline tasks only.
Signed-off-by: Dario Faggioli <raistlin@linux.it>
Signed-off-by: Juri Lelli <juri.lelli@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1383831828-15501-9-git-send-email-juri.lelli@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
ftrace_trace_function is a variable that holds what function will be called
directly by the assembly code (mcount). If just a single function is
registered and it handles recursion itself, then the assembly will call that
function directly without any helper function. It also passes in the
ftrace_op that was registered with the callback. The ftrace_op to send is
stored in the function_trace_op variable.
The ftrace_trace_function and function_trace_op needs to be coordinated such
that the called callback wont be called with the wrong ftrace_op, otherwise
bad things can happen if it expected a different op. Luckily, there's no
callback that doesn't use the helper functions that requires this. But
there soon will be and this needs to be fixed.
Use a set_function_trace_op to store the ftrace_op to set the
function_trace_op to when it is safe to do so (during the update function
within the breakpoint or stop machine calls). Or if dynamic ftrace is not
being used (static tracing) then we have to do a bit more synchronization
when the ftrace_trace_function is set as that takes affect immediately
(as oppose to dynamic ftrace doing it with the modification of the trampoline).
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently there's no way to know what triggers exist on a kernel without
looking at the source of the kernel or randomly trying out triggers.
Instead of creating another file in the debugfs system, simply show
what available triggers are there when cat'ing the trigger file when
it has no events:
[root /sys/kernel/debug/tracing]# cat events/sched/sched_switch/trigger
# Available triggers:
# traceon traceoff snapshot stacktrace enable_event disable_event
This stays consistent with other debugfs files where meta data like
this is always proceeded with a '#' at the start of the line so that
tools can strip these out.
Link: http://lkml.kernel.org/r/20140107103548.0a84536d@gandalf.local.home
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The event trigger code that checks for callback triggers before and
after recording of an event has lots of flags checks. This code is
duplicated throughout the ftrace events, kprobes and system calls.
They all do the exact same checks against the event flags.
Added helper functions ftrace_trigger_soft_disabled(),
event_trigger_unlock_commit() and event_trigger_unlock_commit_regs()
that consolidated the code and these are used instead.
Link: http://lkml.kernel.org/r/20140106222703.5e7dbba2@gandalf.local.home
Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The counters for the traceon and traceoff are only suppose to decrement
when the trigger enables or disables tracing. It is not suppose to decrement
every time the event is hit.
Only decrement the counter if the trigger actually did something.
Link: http://lkml.kernel.org/r/20140106223124.0e5fd0b4@gandalf.local.home
Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
There's no reason to use double-underscores for any variable name in
ftrace_syscall_enter()/exit(), since those functions aren't generated
and there's no need to avoid namespace collisions as with the event
macros, which is where the original invocation code came from.
Link: http://lkml.kernel.org/r/0b489c9d1f7ee315cff60fa0e4c2b433ade8ae0d.1389036657.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add code to the kprobe/kretprobe event functions that will invoke any
event triggers associated with a probe's ftrace_event_file.
The code to do this is very similar to the invocation code already
used to invoke the triggers associated with static events and
essentially replaces the existing soft-disable checks with a superset
that preserves the original behavior but adds the bits needed to
support event triggers.
Link: http://lkml.kernel.org/r/f2d49f157b608070045fdb26c9564d5a05a5a7d0.1389036657.git.tom.zanussi@linux.intel.com
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When kprobe-based dynamic event tracer is not enabled, it caused
following build error:
kernel/built-in.o: In function `traceprobe_update_arg':
(.text+0x10c8dd): undefined reference to `fetch_symbol_u8'
kernel/built-in.o: In function `traceprobe_update_arg':
(.text+0x10c8e9): undefined reference to `fetch_symbol_u16'
kernel/built-in.o: In function `traceprobe_update_arg':
(.text+0x10c8f5): undefined reference to `fetch_symbol_u32'
kernel/built-in.o: In function `traceprobe_update_arg':
(.text+0x10c901): undefined reference to `fetch_symbol_u64'
kernel/built-in.o: In function `traceprobe_update_arg':
(.text+0x10c909): undefined reference to `fetch_symbol_string'
kernel/built-in.o: In function `traceprobe_update_arg':
(.text+0x10c913): undefined reference to `fetch_symbol_string_size'
...
It was due to the fetch methods are referred from CHECK_FETCH_FUNCS
macro and since it was only defined in trace_kprobe.c. Move NULL
definition of such fetch functions to the header file.
Note, it also requires CONFIG_BRANCH_PROFILING enabled to trigger
this failure as well. This is because the "fetch_symbol_*" variables
are referenced in a "else if" statement that will only call
update_symbol_cache(), which is a static inline stub function
when CONFIG_KPROBE_EVENT is not enabled. gcc is smart enough
to optimize this "else if" out and that also removes the code that
references the undefined variables.
But when BRANCH_PROFILING is enabled, it fools gcc into keeping
the if statement around and thus references the undefined symbols
and fails to build.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Enable to fetch data from a file offset. Currently it only supports
fetching from same binary uprobe set. It'll translate the file offset
to a proper virtual address in the process.
The syntax is "@+OFFSET" as it does similar to normal memory fetching
(@ADDR) which does no address translation.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Enable to fetch other types of argument for the uprobes. IOW, we can
access stack, memory, deref, bitfield and retval from uprobes now.
The format for the argument types are same as kprobes (but @SYMBOL
type is not supported for uprobes), i.e:
@ADDR : Fetch memory at ADDR
$stackN : Fetch Nth entry of stack (N >= 0)
$stack : Fetch stack address
$retval : Fetch return value
+|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address
Note that the retval only can be used with uretprobes.
Original-patch-by: Hyeoncheol Lee <cheol.lee@lge.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Hyeoncheol Lee <cheol.lee@lge.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Fetching from user space should be done in a non-atomic context. So
use a per-cpu buffer and copy its content to the ring buffer
atomically. Note that we can migrate during accessing user memory
thus use a per-cpu mutex to protect concurrent accesses.
This is needed since we'll be able to fetch args from an user memory
which can be swapped out. Before that uprobes could fetch args from
registers only which saved in a kernel space.
While at it, use __get_data_size() and store_trace_args() to reduce
code duplication. And add struct uprobe_cpu_buffer and its helpers as
suggested by Oleg.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Currently uprobes don't pass is_return to the argument parser so that
it cannot make use of "$retval" fetch method since it only works for
return probes.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Use separate method to fetch from memory. Move existing functions to
trace_kprobe.c and make them static. Also add new memory fetch
implementation for uprobes.
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The deref fetch methods access a memory region but it assumes that
it's a kernel memory since uprobes does not support them.
Add ->fetch and ->fetch_size member in order to provide a proper
access methods for supporting uprobes.
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Hyeoncheol Lee <cheol.lee@lge.com>
[namhyung@kernel.org: Split original patch into pieces as requested]
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Move existing functions to trace_kprobe.c and add NULL entries to the
uprobes fetch type table. I don't make them static since some generic
routines like update/free_XXX_fetch_param() require pointers to the
functions.
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Use separate method to fetch from stack. Move existing functions to
trace_kprobe.c and make them static. Also add new stack fetch
implementation for uprobes.
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Use separate fetch_type_table for kprobes and uprobes. It currently
shares all fetch methods but some of them will be implemented
differently later.
This is not to break build if [ku]probes is configured alone (like
!CONFIG_KPROBE_EVENT and CONFIG_UPROBE_EVENT). So I added '__weak'
to the table declaration so that it can be safely omitted when it
configured out.
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Move fetch function helper macros/functions to the header file and
make them external. This is preparation of supporting uprobe fetch
table in next patch.
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The set_print_fmt() functions are implemented almost same for
[ku]probes. Move it to a common place and get rid of the duplication.
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The __get_data_size() and store_trace_args() will be used by uprobes
too. Move them to a common location.
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Convert struct trace_uprobe to make use of the common trace_probe
structure.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
There are functions that can be shared to both of kprobes and uprobes.
Separate common data structure to struct trace_probe and use it from
the shared functions.
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The print format of s32 type was "ld" and it's casted to "long". So
it turned out to print 4294967295 for "-1" on 64-bit systems. Not
sure whether it worked well on 32-bit systems.
Anyway, it doesn't need to have cast argument at all since it already
casted using type pointer - just get rid of it. Thanks to Oleg for
pointing that out.
And print 0x prefix for unsigned type as it shows hex numbers.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The uprobe syntax requires an offset after a file path not a symbol.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The filter field of the event_trigger_data structure is protected under
RCU sched locks. It was not annotated as such, and after doing so,
sparse pointed out several locations that required fix ups.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Trace event triggers added a lseek that uses the ftrace_filter_lseek()
function. Unfortunately, when function tracing is not configured in
that function is not defined and the kernel fails to build.
This is the second time that function was added to a file ops and
it broke the build due to requiring special config dependencies.
Make a generic tracing_lseek() that all the tracing utilities may
use.
Also, modify the old ftrace_filter_lseek() to return 0 instead of
1 on WRONLY. Not sure why it was a 1 as that does not make sense.
This also changes the old tracing_seek() to modify the file pos
pointer on WRONLY as well.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Merge tag 'v3.13-rc6' into for-3.14/core
Needed to bring blk-mq uptodate, since changes have been going in
since for-3.14/core was established.
Fixup merge issues related to the immutable biovec changes.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Conflicts:
block/blk-flush.c
fs/btrfs/check-integrity.c
fs/btrfs/extent_io.c
fs/btrfs/scrub.c
fs/logfs/dev_bdev.c
Add a generic event_command.set_trigger_filter() op implementation and
have the current set of trigger commands use it - this essentially
gives them all support for filters.
Syntactically, filters are supported by adding 'if <filter>' just
after the command, in which case only events matching the filter will
invoke the trigger. For example, to add a filter to an
enable/disable_event command:
echo 'enable_event:system:event if common_pid == 999' > \
.../othersys/otherevent/trigger
The above command will only enable the system:event event if the
common_pid field in the othersys:otherevent event is 999.
As another example, to add a filter to a stacktrace command:
echo 'stacktrace if common_pid == 999' > \
.../somesys/someevent/trigger
The above command will only trigger a stacktrace if the common_pid
field in the event is 999.
The filter syntax is the same as that described in the 'Event
filtering' section of Documentation/trace/events.txt.
Because triggers can now use filters, the trigger-invoking logic needs
to be moved in those cases - e.g. for ftrace_raw_event_calls, if a
trigger has a filter associated with it, the trigger invocation now
needs to happen after the { assign; } part of the call, in order for
the trigger condition to be tested.
There's still a SOFT_DISABLED-only check at the top of e.g. the
ftrace_raw_events function, so when an event is soft disabled but not
because of the presence of a trigger, the original SOFT_DISABLED
behavior remains unchanged.
There's also a bit of trickiness in that some triggers need to avoid
being invoked while an event is currently in the process of being
logged, since the trigger may itself log data into the trace buffer.
Thus we make sure the current event is committed before invoking those
triggers. To do that, we split the trigger invocation in two - the
first part (event_triggers_call()) checks the filter using the current
trace record; if a command has the post_trigger flag set, it sets a
bit for itself in the return value, otherwise it directly invoks the
trigger. Once all commands have been either invoked or set their
return flag, event_triggers_call() returns. The current record is
then either committed or discarded; if any commands have deferred
their triggers, those commands are finally invoked following the close
of the current event by event_triggers_post_call().
To simplify the above and make it more efficient, the TRIGGER_COND bit
is introduced, which is set only if a soft-disabled trigger needs to
use the log record for filter testing or needs to wait until the
current log record is closed.
The syscall event invocation code is also changed in analogous ways.
Because event triggers need to be able to create and free filters,
this also adds a couple external wrappers for the existing
create_filter and free_filter functions, which are too generic to be
made extern functions themselves.
Link: http://lkml.kernel.org/r/7164930759d8719ef460357f143d995406e4eead.1382622043.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Now that event triggers use ftrace_event_file(), it needs to be outside
the #ifdef CONFIG_DYNAMIC_FTRACE, as it can now be used when that is
not defined.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add 'enable_event' and 'disable_event' event_command commands.
enable_event and disable_event event triggers are added by the user
via these commands in a similar way and using practically the same
syntax as the analagous 'enable_event' and 'disable_event' ftrace
function commands, but instead of writing to the set_ftrace_filter
file, the enable_event and disable_event triggers are written to the
per-event 'trigger' files:
echo 'enable_event:system:event' > .../othersys/otherevent/trigger
echo 'disable_event:system:event' > .../othersys/otherevent/trigger
The above commands will enable or disable the 'system:event' trace
events whenever the othersys:otherevent events are hit.
This also adds a 'count' version that limits the number of times the
command will be invoked:
echo 'enable_event:system:event:N' > .../othersys/otherevent/trigger
echo 'disable_event:system:event:N' > .../othersys/otherevent/trigger
Where N is the number of times the command will be invoked.
The above commands will will enable or disable the 'system:event'
trace events whenever the othersys:otherevent events are hit, but only
N times.
This also makes the find_event_file() helper function extern, since
it's useful to use from other places, such as the event triggers code,
so make it accessible.
Link: http://lkml.kernel.org/r/f825f3048c3f6b026ee37ae5825f9fc373451828.1382622043.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add 'stacktrace' event_command. stacktrace event triggers are added
by the user via this command in a similar way and using practically
the same syntax as the analogous 'stacktrace' ftrace function command,
but instead of writing to the set_ftrace_filter file, the stacktrace
event trigger is written to the per-event 'trigger' files:
echo 'stacktrace' > .../tracing/events/somesys/someevent/trigger
The above command will turn on stacktraces for someevent i.e. whenever
someevent is hit, a stacktrace will be logged.
This also adds a 'count' version that limits the number of times the
command will be invoked:
echo 'stacktrace:N' > .../tracing/events/somesys/someevent/trigger
Where N is the number of times the command will be invoked.
The above command will log N stacktraces for someevent i.e. whenever
someevent is hit N times, a stacktrace will be logged.
Link: http://lkml.kernel.org/r/0c30c008a0828c660aa0e1bbd3255cf179ed5c30.1382622043.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add 'snapshot' event_command. snapshot event triggers are added by
the user via this command in a similar way and using practically the
same syntax as the analogous 'snapshot' ftrace function command, but
instead of writing to the set_ftrace_filter file, the snapshot event
trigger is written to the per-event 'trigger' files:
echo 'snapshot' > .../somesys/someevent/trigger
The above command will turn on snapshots for someevent i.e. whenever
someevent is hit, a snapshot will be done.
This also adds a 'count' version that limits the number of times the
command will be invoked:
echo 'snapshot:N' > .../somesys/someevent/trigger
Where N is the number of times the command will be invoked.
The above command will snapshot N times for someevent i.e. whenever
someevent is hit N times, a snapshot will be done.
Also adds a new tracing_alloc_snapshot() function - the existing
tracing_snapshot_alloc() function is a special version of
tracing_snapshot() that also does the snapshot allocation - the
snapshot triggers would like to be able to do just the allocation but
not take a snapshot; the existing tracing_snapshot_alloc() in turn now
also calls tracing_alloc_snapshot() underneath to do that allocation.
Link: http://lkml.kernel.org/r/c9524dd07ce01f9dcbd59011290e0a8d5b47d7ad.1382622043.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
[ fix up from kbuild test robot <fengguang.wu@intel.com report ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add 'traceon' and 'traceoff' event_command commands. traceon and
traceoff event triggers are added by the user via these commands in a
similar way and using practically the same syntax as the analagous
'traceon' and 'traceoff' ftrace function commands, but instead of
writing to the set_ftrace_filter file, the traceon and traceoff
triggers are written to the per-event 'trigger' files:
echo 'traceon' > .../tracing/events/somesys/someevent/trigger
echo 'traceoff' > .../tracing/events/somesys/someevent/trigger
The above command will turn tracing on or off whenever someevent is
hit.
This also adds a 'count' version that limits the number of times the
command will be invoked:
echo 'traceon:N' > .../tracing/events/somesys/someevent/trigger
echo 'traceoff:N' > .../tracing/events/somesys/someevent/trigger
Where N is the number of times the command will be invoked.
The above commands will will turn tracing on or off whenever someevent
is hit, but only N times.
Some common register/unregister_trigger() implementations of the
event_command reg()/unreg() callbacks are also provided, which add and
remove trigger instances to the per-event list of triggers, and
arm/disarm them as appropriate. event_trigger_callback() is a
general-purpose event_command func() implementation that orchestrates
command parsing and registration for most normal commands.
Most event commands will use these, but some will override and
possibly reuse them.
The event_trigger_init(), event_trigger_free(), and
event_trigger_print() functions are meant to be common implementations
of the event_trigger_ops init(), free(), and print() ops,
respectively.
Most trigger_ops implementations will use these, but some will
override and possibly reuse them.
Link: http://lkml.kernel.org/r/00a52816703b98d2072947478dd6e2d70cde5197.1382622043.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add a 'trigger' file for each trace event, enabling 'trace event
triggers' to be set for trace events.
'trace event triggers' are patterned after the existing 'ftrace
function triggers' implementation except that triggers are written to
per-event 'trigger' files instead of to a single file such as the
'set_ftrace_filter' used for ftrace function triggers.
The implementation is meant to be entirely separate from ftrace
function triggers, in order to keep the respective implementations
relatively simple and to allow them to diverge.
The event trigger functionality is built on top of SOFT_DISABLE
functionality. It adds a TRIGGER_MODE bit to the ftrace_event_file
flags which is checked when any trace event fires. Triggers set for a
particular event need to be checked regardless of whether that event
is actually enabled or not - getting an event to fire even if it's not
enabled is what's already implemented by SOFT_DISABLE mode, so trigger
mode directly reuses that. Event trigger essentially inherit the soft
disable logic in __ftrace_event_enable_disable() while adding a bit of
logic and trigger reference counting via tm_ref on top of that in a
new trace_event_trigger_enable_disable() function. Because the base
__ftrace_event_enable_disable() code now needs to be invoked from
outside trace_events.c, a wrapper is also added for those usages.
The triggers for an event are actually invoked via a new function,
event_triggers_call(), and code is also added to invoke them for
ftrace_raw_event calls as well as syscall events.
The main part of the patch creates a new trace_events_trigger.c file
to contain the trace event triggers implementation.
The standard open, read, and release file operations are implemented
here.
The open() implementation sets up for the various open modes of the
'trigger' file. It creates and attaches the trigger iterator and sets
up the command parser. If opened for reading set up the trigger
seq_ops.
The read() implementation parses the event trigger written to the
'trigger' file, looks up the trigger command, and passes it along to
that event_command's func() implementation for command-specific
processing.
The release() implementation does whatever cleanup is needed to
release the 'trigger' file, like releasing the parser and trigger
iterator, etc.
A couple of functions for event command registration and
unregistration are added, along with a list to add them to and a mutex
to protect them, as well as an (initially empty) registration function
to add the set of commands that will be added by future commits, and
call to it from the trace event initialization code.
also added are a couple trigger-specific data structures needed for
these implementations such as a trigger iterator and a struct for
trigger-specific data.
A couple structs consisting mostly of function meant to be implemented
in command-specific ways, event_command and event_trigger_ops, are
used by the generic event trigger command implementations. They're
being put into trace.h alongside the other trace_event data structures
and functions, in the expectation that they'll be needed in several
trace_event-related files such as trace_events_trigger.c and
trace_events.c.
The event_command.func() function is meant to be called by the trigger
parsing code in order to add a trigger instance to the corresponding
event. It essentially coordinates adding a live trigger instance to
the event, and arming the triggering the event.
Every event_command func() implementation essentially does the
same thing for any command:
- choose ops - use the value of param to choose either a number or
count version of event_trigger_ops specific to the command
- do the register or unregister of those ops
- associate a filter, if specified, with the triggering event
The reg() and unreg() ops allow command-specific implementations for
event_trigger_op registration and unregistration, and the
get_trigger_ops() op allows command-specific event_trigger_ops
selection to be parameterized. When a trigger instance is added, the
reg() op essentially adds that trigger to the triggering event and
arms it, while unreg() does the opposite. The set_filter() function
is used to associate a filter with the trigger - if the command
doesn't specify a set_filter() implementation, the command will ignore
filters.
Each command has an associated trigger_type, which serves double duty,
both as a unique identifier for the command as well as a value that
can be used for setting a trigger mode bit during trigger invocation.
The signature of func() adds a pointer to the event_command struct,
used to invoke those functions, along with a command_data param that
can be passed to the reg/unreg functions. This allows func()
implementations to use command-specific blobs and supports code
re-use.
The event_trigger_ops.func() command corrsponds to the trigger 'probe'
function that gets called when the triggering event is actually
invoked. The other functions are used to list the trigger when
needed, along with a couple mundane book-keeping functions.
This also moves event_file_data() into trace.h so it can be used
outside of trace_events.c.
Link: http://lkml.kernel.org/r/316d95061accdee070aac8e5750afba0192fa5b9.1382622043.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Idea-by: Steve Rostedt <rostedt@goodmis.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The problem is that the profiler only initializes the online
CPUs, and not possible CPUs. This causes issues if the user takes
CPUs online or offline while the profiler is running.
If we online a CPU after starting the profiler, we lose all the
trace information on the CPU going online.
If we offline a CPU after running a test and start a new test, it
will not clear the old data from that CPU.
This bug causes incorrect data to be reported to the user if they
online or offline CPUs during the profiling.
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Merge tag 'trace-fixes-v3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull ftrace fix from Steven Rostedt:
"This fixes a long standing bug in the ftrace profiler. The problem is
that the profiler only initializes the online CPUs, and not possible
CPUs. This causes issues if the user takes CPUs online or offline
while the profiler is running.
If we online a CPU after starting the profiler, we lose all the trace
information on the CPU going online.
If we offline a CPU after running a test and start a new test, it will
not clear the old data from that CPU.
This bug causes incorrect data to be reported to the user if they
online or offline CPUs during the profiling"
* tag 'trace-fixes-v3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Initialize the ftrace profiler for each possible cpu
Ftrace currently initializes only the online CPUs. This implementation has
two problems:
- If we online a CPU after we enable the function profile, and then run the
test, we will lose the trace information on that CPU.
Steps to reproduce:
# echo 0 > /sys/devices/system/cpu/cpu1/online
# cd <debugfs>/tracing/
# echo <some function name> >> set_ftrace_filter
# echo 1 > function_profile_enabled
# echo 1 > /sys/devices/system/cpu/cpu1/online
# run test
- If we offline a CPU before we enable the function profile, we will not clear
the trace information when we enable the function profile. It will trouble
the users.
Steps to reproduce:
# cd <debugfs>/tracing/
# echo <some function name> >> set_ftrace_filter
# echo 1 > function_profile_enabled
# run test
# cat trace_stat/function*
# echo 0 > /sys/devices/system/cpu/cpu1/online
# echo 0 > function_profile_enabled
# echo 1 > function_profile_enabled
# cat trace_stat/function*
# run test
# cat trace_stat/function*
So it is better that we initialize the ftrace profiler for each possible cpu
every time we enable the function profile instead of just the online ones.
Link: http://lkml.kernel.org/r/1387178401-10619-1-git-send-email-miaox@cn.fujitsu.com
Cc: stable@vger.kernel.org # 2.6.31+
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
all events. This was prevalent when FTRACE_SELFTEST was enabled which
enables all events several times, and caused the system bootup to
pause for over a minute.
This was tracked down to an addition of a synchronize_sched() performed
when system call tracepoints are unregistered.
The synchronize_sched() is needed between the unregistering of the
system call tracepoint and a deletion of a tracing instance buffer.
But placing the synchronize_sched() in the unreg of *every* system call
tracepoint is a bit overboard. A single synchronize_sched() before
the deletion of the instance is sufficient.
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Merge tag 'trace-fixes-3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fix from Steven Rostedt:
"A regression showed up that there's a large delay when enabling all
events. This was prevalent when FTRACE_SELFTEST was enabled which
enables all events several times, and caused the system bootup to
pause for over a minute.
This was tracked down to an addition of a synchronize_sched()
performed when system call tracepoints are unregistered.
The synchronize_sched() is needed between the unregistering of the
system call tracepoint and a deletion of a tracing instance buffer.
But placing the synchronize_sched() in the unreg of *every* system
call tracepoint is a bit overboard. A single synchronize_sched()
before the deletion of the instance is sufficient"
* tag 'trace-fixes-3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Only run synchronize_sched() at instance deletion time
It has been reported that boot up with FTRACE_SELFTEST enabled can take a
very long time. There can be stalls of over a minute.
This was tracked down to the synchronize_sched() called when a system call
event is disabled. As the self tests enable and disable thousands of events,
this makes the synchronize_sched() get called thousands of times.
The synchornize_sched() was added with d562aff93b "tracing: Add support
for SOFT_DISABLE to syscall events" which caused this regression (added
in 3.13-rc1).
The synchronize_sched() is to protect against the events being accessed
when a tracer instance is being deleted. When an instance is being deleted
all the events associated to it are unregistered. The synchronize_sched()
makes sure that no more users are running when it finishes.
Instead of calling synchronize_sched() for all syscall events, we only
need to call it once, after the events are unregistered and before the
instance is deleted. The event_mutex is held during this action to
prevent new users from enabling events.
Link: http://lkml.kernel.org/r/20131203124120.427b9661@gandalf.local.home
Reported-by: Petr Mladek <pmladek@suse.cz>
Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Acked-by: Petr Mladek <pmladek@suse.cz>
Tested-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Pull perf fixes from Ingo Molnar:
"Misc kernel and tooling fixes"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tools lib traceevent: Fix conversion of pointer to integer of different size
perf/trace: Properly use u64 to hold event_id
perf: Remove fragile swevent hlist optimization
ftrace, perf: Avoid infinite event generation loop
tools lib traceevent: Fix use of multiple options in processing field
perf header: Fix possible memory leaks in process_group_desc()
perf header: Fix bogus group name
perf tools: Tag thread comm as overriden
Commit 8c4f3c3fa9 "ftrace: Check module functions being traced on reload"
fixed module loading and unloading with respect to function tracing, but
it missed the function graph tracer. If you perform the following
# cd /sys/kernel/debug/tracing
# echo function_graph > current_tracer
# modprobe nfsd
# echo nop > current_tracer
You'll get the following oops message:
------------[ cut here ]------------
WARNING: CPU: 2 PID: 2910 at /linux.git/kernel/trace/ftrace.c:1640 __ftrace_hash_rec_update.part.35+0x168/0x1b9()
Modules linked in: nfsd exportfs nfs_acl lockd ipt_MASQUERADE sunrpc ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables uinput snd_hda_codec_idt
CPU: 2 PID: 2910 Comm: bash Not tainted 3.13.0-rc1-test #7
Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS SDBLI944.86P 05/08/2007
0000000000000668 ffff8800787efcf8 ffffffff814fe193 ffff88007d500000
0000000000000000 ffff8800787efd38 ffffffff8103b80a 0000000000000668
ffffffff810b2b9a ffffffff81a48370 0000000000000001 ffff880037aea000
Call Trace:
[<ffffffff814fe193>] dump_stack+0x4f/0x7c
[<ffffffff8103b80a>] warn_slowpath_common+0x81/0x9b
[<ffffffff810b2b9a>] ? __ftrace_hash_rec_update.part.35+0x168/0x1b9
[<ffffffff8103b83e>] warn_slowpath_null+0x1a/0x1c
[<ffffffff810b2b9a>] __ftrace_hash_rec_update.part.35+0x168/0x1b9
[<ffffffff81502f89>] ? __mutex_lock_slowpath+0x364/0x364
[<ffffffff810b2cc2>] ftrace_shutdown+0xd7/0x12b
[<ffffffff810b47f0>] unregister_ftrace_graph+0x49/0x78
[<ffffffff810c4b30>] graph_trace_reset+0xe/0x10
[<ffffffff810bf393>] tracing_set_tracer+0xa7/0x26a
[<ffffffff810bf5e1>] tracing_set_trace_write+0x8b/0xbd
[<ffffffff810c501c>] ? ftrace_return_to_handler+0xb2/0xde
[<ffffffff811240a8>] ? __sb_end_write+0x5e/0x5e
[<ffffffff81122aed>] vfs_write+0xab/0xf6
[<ffffffff8150a185>] ftrace_graph_caller+0x85/0x85
[<ffffffff81122dbd>] SyS_write+0x59/0x82
[<ffffffff8150a185>] ftrace_graph_caller+0x85/0x85
[<ffffffff8150a2d2>] system_call_fastpath+0x16/0x1b
---[ end trace 940358030751eafb ]---
The above mentioned commit didn't go far enough. Well, it covered the
function tracer by adding checks in __register_ftrace_function(). The
problem is that the function graph tracer circumvents that (for a slight
efficiency gain when function graph trace is running with a function
tracer. The gain was not worth this).
The problem came with ftrace_startup() which should always be called after
__register_ftrace_function(), if you want this bug to be completely fixed.
Anyway, this solution moves __register_ftrace_function() inside of
ftrace_startup() and removes the need to call them both.
Reported-by: Dave Wysochanski <dwysocha@redhat.com>
Fixes: ed926f9b35 ("ftrace: Use counters to enable functions to trace")
Cc: stable@vger.kernel.org # 3.0+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The 64-bit attr.config value for perf trace events was being copied into
an "int" before doing a comparison, meaning the top 32 bits were
being truncated.
As far as I can tell this didn't cause any errors, but it did mean
it was possible to create valid aliases for all the tracepoint ids
which I don't think was intended. (For example, 0xffffffff00000018
and 0x18 both enable the same tracepoint).
Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1311151236100.11932@vincent-weaver-1.um.maine.edu
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Vince's perf-trinity fuzzer found yet another 'interesting' problem.
When we sample the irq_work_exit tracepoint with period==1 (or
PERF_SAMPLE_PERIOD) and we add an fasync SIGNAL handler we create an
infinite event generation loop:
,-> <IPI>
| irq_work_exit() ->
| trace_irq_work_exit() ->
| ...
| __perf_event_overflow() -> (due to fasync)
| irq_work_queue() -> (irq_work_list must be empty)
'--------- arch_irq_work_raise()
Similar things can happen due to regular poll() wakeups if we exceed
the ring-buffer wakeup watermark, or have an event_limit.
To avoid this, dis-allow sampling this particular tracepoint.
In order to achieve this, create a special perf_perm function pointer
for each event and call this (when set) on trying to create a
tracepoint perf event.
[ roasted: use expr... to allow for ',' in your expression ]
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20131114152304.GC5364@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The only real feature that was added this release is from Namhyung Kim,
who introduced "set_graph_notrace" filter that lets you run the function
graph tracer and not trace particular functions and their call chain.
Tom Zanussi added some updates to the ftrace multibuffer tracing that
made it more consistent with the top level tracing.
One of the fixes for perf function tracing required an API change in
RCU; the addition of "rcu_is_watching()". As Paul McKenney is pushing
that change in this release too, he gave me a branch that included
all the changes to get that working, and I pulled that into my tree
in order to complete the perf function tracing fix.
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Merge tag 'trace-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing update from Steven Rostedt:
"This batch of changes is mostly clean ups and small bug fixes. The
only real feature that was added this release is from Namhyung Kim,
who introduced "set_graph_notrace" filter that lets you run the
function graph tracer and not trace particular functions and their
call chain.
Tom Zanussi added some updates to the ftrace multibuffer tracing that
made it more consistent with the top level tracing.
One of the fixes for perf function tracing required an API change in
RCU; the addition of "rcu_is_watching()". As Paul McKenney is pushing
that change in this release too, he gave me a branch that included all
the changes to get that working, and I pulled that into my tree in
order to complete the perf function tracing fix"
* tag 'trace-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Add rcu annotation for syscall trace descriptors
tracing: Do not use signed enums with unsigned long long in fgragh output
tracing: Remove unused function ftrace_off_permanent()
tracing: Do not assign filp->private_data to freed memory
tracing: Add helper function tracing_is_disabled()
tracing: Open tracer when ftrace_dump_on_oops is used
tracing: Add support for SOFT_DISABLE to syscall events
tracing: Make register/unregister_ftrace_command __init
tracing: Update event filters for multibuffer
recordmcount.pl: Add support for __fentry__
ftrace: Have control op function callback only trace when RCU is watching
rcu: Do not trace rcu_is_watching() functions
ftrace/x86: skip over the breakpoint for ftrace caller
trace/trace_stat: use rbtree postorder iteration helper instead of opencoding
ftrace: Add set_graph_notrace filter
ftrace: Narrow down the protected area of graph_lock
ftrace: Introduce struct ftrace_graph_data
ftrace: Get rid of ftrace_graph_filter_enabled
tracing: Fix potential out-of-bounds in trace_get_user()
tracing: Show more exact help information about snapshot
Pull block IO core updates from Jens Axboe:
"This is the pull request for the core changes in the block layer for
3.13. It contains:
- The new blk-mq request interface.
This is a new and more scalable queueing model that marries the
best part of the request based interface we currently have (which
is fully featured, but scales poorly) and the bio based "interface"
which the new drivers for high IOPS devices end up using because
it's much faster than the request based one.
The bio interface has no block layer support, since it taps into
the stack much earlier. This means that drivers end up having to
implement a lot of functionality on their own, like tagging,
timeout handling, requeue, etc. The blk-mq interface provides all
these. Some drivers even provide a switch to select bio or rq and
has code to handle both, since things like merging only works in
the rq model and hence is faster for some workloads. This is a
huge mess. Conversion of these drivers nets us a substantial code
reduction. Initial results on converting SCSI to this model even
shows an 8x improvement on single queue devices. So while the
model was intended to work on the newer multiqueue devices, it has
substantial improvements for "classic" hardware as well. This code
has gone through extensive testing and development, it's now ready
to go. A pull request is coming to convert virtio-blk to this
model will be will be coming as well, with more drivers scheduled
for 3.14 conversion.
- Two blktrace fixes from Jan and Chen Gang.
- A plug merge fix from Alireza Haghdoost.
- Conversion of __get_cpu_var() from Christoph Lameter.
- Fix for sector_div() with 64-bit divider from Geert Uytterhoeven.
- A fix for a race between request completion and the timeout
handling from Jeff Moyer. This is what caused the merge conflict
with blk-mq/core, in case you are looking at that.
- A dm stacking fix from Mike Snitzer.
- A code consolidation fix and duplicated code removal from Kent
Overstreet.
- A handful of block bug fixes from Mikulas Patocka, fixing a loop
crash and memory corruption on blk cg.
- Elevator switch bug fix from Tomoki Sekiyama.
A heads-up that I had to rebase this branch. Initially the immutable
bio_vecs had been queued up for inclusion, but a week later, it became
clear that it wasn't fully cooked yet. So the decision was made to
pull this out and postpone it until 3.14. It was a straight forward
rebase, just pruning out the immutable series and the later fixes of
problems with it. The rest of the patches applied directly and no
further changes were made"
* 'for-3.13/core' of git://git.kernel.dk/linux-block: (31 commits)
block: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO
block: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO
block: Do not call sector_div() with a 64-bit divisor
kernel: trace: blktrace: remove redundent memcpy() in compat_blk_trace_setup()
block: Consolidate duplicated bio_trim() implementations
block: Use rw_copy_check_uvector()
block: Enable sysfs nomerge control for I/O requests in the plug list
block: properly stack underlying max_segment_size to DM device
elevator: acquire q->sysfs_lock in elevator_change()
elevator: Fix a race in elevator switching and md device initialization
block: Replace __get_cpu_var uses
bdi: test bdi_init failure
block: fix a probe argument to blk_register_region
loop: fix crash if blk_alloc_queue fails
blk-core: Fix memory corruption if blkcg_init_queue fails
block: fix race between request completion and timeout handling
blktrace: Send BLK_TN_PROCESS events to all running traces
blk-mq: don't disallow request merges for req->special being set
blk-mq: mq plug list breakage
blk-mq: fix for flush deadlock
...
Pull scheduler changes from Ingo Molnar:
"The main changes in this cycle are:
- (much) improved CONFIG_NUMA_BALANCING support from Mel Gorman, Rik
van Riel, Peter Zijlstra et al. Yay!
- optimize preemption counter handling: merge the NEED_RESCHED flag
into the preempt_count variable, by Peter Zijlstra.
- wait.h fixes and code reorganization from Peter Zijlstra
- cfs_bandwidth fixes from Ben Segall
- SMP load-balancer cleanups from Peter Zijstra
- idle balancer improvements from Jason Low
- other fixes and cleanups"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (129 commits)
ftrace, sched: Add TRACE_FLAG_PREEMPT_RESCHED
stop_machine: Fix race between stop_two_cpus() and stop_cpus()
sched: Remove unnecessary iteration over sched domains to update nr_busy_cpus
sched: Fix asymmetric scheduling for POWER7
sched: Move completion code from core.c to completion.c
sched: Move wait code from core.c to wait.c
sched: Move wait.c into kernel/sched/
sched/wait: Fix __wait_event_interruptible_lock_irq_timeout()
sched: Avoid throttle_cfs_rq() racing with period_timer stopping
sched: Guarantee new group-entities always have weight
sched: Fix hrtimer_cancel()/rq->lock deadlock
sched: Fix cfs_bandwidth misuse of hrtimer_expires_remaining
sched: Fix race on toggling cfs_bandwidth_used
sched: Remove extra put_online_cpus() inside sched_setaffinity()
sched/rt: Fix task_tick_rt() comment
sched/wait: Fix build breakage
sched/wait: Introduce prepare_to_wait_event()
sched/wait: Add ___wait_cond_timeout() to wait_event*_timeout() too
sched: Remove get_online_cpus() usage
sched: Fix race in migrate_swap_stop()
...
sparse complains about the enter/exit_sysycall_files[] variables being
dereferenced with rcu_dereference_sched(). The fields need to be
annotated with __rcu.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Since the introduction of PREEMPT_NEED_RESCHED in:
f27dde8dee ("sched: Add NEED_RESCHED to the preempt_count")
we need to be able to look at both TIF_NEED_RESCHED and
PREEMPT_NEED_RESCHED to understand the full preemption behaviour.
Add it to the trace output.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Link: http://lkml.kernel.org/r/20131004152826.GP3081@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
do_blk_trace_setup() will fully initialize 'buts.name', so can remove
the related memcpy(). And also use BLKTRACE_BDEV_SIZE and ARRAY_SIZE
instead of hard code number '32'.
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently each task sends BLK_TN_PROCESS event to the first traced
device it interacts with after a new trace is started. When there are
several traced devices and the task accesses more devices, this logic
can result in BLK_TN_PROCESS being sent several times to some devices
while it is never sent to other devices. Thus blkparse doesn't display
command name when parsing some blktrace files.
Fix the problem by sending BLK_TN_PROCESS event to all traced devices
when a task interacts with any of them.
Signed-off-by: Jan Kara <jack@suse.cz>
Review-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The duration field of print_graph_duration() can also be used
to do the space filling by passing an enum in it:
DURATION_FILL_FULL
DURATION_FILL_START
DURATION_FILL_END
The problem is that these are enums and defined as negative,
but the duration field is unsigned long long. Most archs are
fine with this but blackfin fails to compile because of it:
kernel/built-in.o: In function `print_graph_duration':
kernel/trace/trace_functions_graph.c:782: undefined reference to `__ucmpdi2'
Overloading a unsigned long long with an signed enum is just
bad in principle. We can accomplish the same thing by using
part of the flags field instead.
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In the past, ftrace_off_permanent() was called if something
strange was detected. But the ftrace_bug() now handles all the
anomolies that can happen with ftrace (function tracing), and there
are no uses of ftrace_off_permanent(). Get rid of it.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In system_tr_open(), the filp->private_data can be assigned the 'dir'
variable even if it was freed. This is on the error path, and is
harmless because the error return code will prevent filp->private_data
from being used. But for correctness, we should not assign it to
a recently freed variable, as that can cause static tools to give
false warnings.
Also have both subsystem_open() and system_tr_open() return -ENODEV
if tracing has been disabled.
Link: http://lkml.kernel.org/r/1383764571-7318-1-git-send-email-geyslan@gmail.com
Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The current default perf paranoid level is "1" which has
"perf_paranoid_kernel()" return false, and giving any operations that
use it, access to normal users. Unfortunately, this includes function
tracing and normal users should not be allowed to enable function
tracing by default.
The proper level is defined at "-1" (full perf access), which
"perf_paranoid_tracepoint_raw()" will only give access to. Use that
check instead for enabling function tracing.
Reported-by: Dave Jones <davej@redhat.com>
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: stable@vger.kernel.org # 3.4+
CVE: CVE-2013-2930
Fixes: ced39002f5 ("ftrace, perf: Add support to use function tracepoint in perf")
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
With ftrace_dump_on_oops, we previously did not open the tracer in
question, sometimes causing the trace output to be useless.
For example, the function_graph tracer with tracing_thresh set dumped via
ftrace_dump_on_oops would show a series of '}' indented at different levels,
but no function names.
call trace->open() (and do a few other fixups copied from the normal dump
path) to make the output more intelligible.
Link: http://lkml.kernel.org/r/1382554197-16961-1-git-send-email-cody@linux.vnet.ibm.com
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The original SOFT_DISABLE patches didn't add support for soft disable
of syscall events; this adds it.
Add an array of ftrace_event_file pointers indexed by syscall number
to the trace array and remove the existing enabled bitmaps, which as a
result are now redundant. The ftrace_event_file structs in turn
contain the soft disable flags we need for per-syscall soft disable
accounting.
Adding ftrace_event_files also means we can remove the USE_CALL_FILTER
bit, thus enabling multibuffer filter support for syscall events.
Link: http://lkml.kernel.org/r/6e72b566e85d8df8042f133efbc6c30e21fb017e.1382620672.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The trace event filters are still tied to event calls rather than
event files, which means you don't get what you'd expect when using
filters in the multibuffer case:
Before:
# echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
# cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
bytes_alloc > 8192
# mkdir /sys/kernel/debug/tracing/instances/test1
# echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter
# cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
bytes_alloc > 2048
# cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter
bytes_alloc > 2048
Setting the filter in tracing/instances/test1/events shouldn't affect
the same event in tracing/events as it does above.
After:
# echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
# cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
bytes_alloc > 8192
# mkdir /sys/kernel/debug/tracing/instances/test1
# echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter
# cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter
bytes_alloc > 8192
# cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter
bytes_alloc > 2048
We'd like to just move the filter directly from ftrace_event_call to
ftrace_event_file, but there are a couple cases that don't yet have
multibuffer support and therefore have to continue using the current
event_call-based filters. For those cases, a new USE_CALL_FILTER bit
is added to the event_call flags, whose main purpose is to keep the
old behavior for those cases until they can be updated with
multibuffer support; at that point, the USE_CALL_FILTER flag (and the
new associated call_filter_check_discard() function) can go away.
The multibuffer support also made filter_current_check_discard()
redundant, so this change removes that function as well and replaces
it with filter_check_discard() (or call_filter_check_discard() as
appropriate).
Link: http://lkml.kernel.org/r/f16e9ce4270c62f46b2e966119225e1c3cca7e60.1382620672.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Dave Jones reported that trinity would be able to trigger the following
back trace:
===============================
[ INFO: suspicious RCU usage. ]
3.10.0-rc2+ #38 Not tainted
-------------------------------
include/linux/rcupdate.h:771 rcu_read_lock() used illegally while idle!
other info that might help us debug this:
RCU used illegally from idle CPU! rcu_scheduler_active = 1, debug_locks = 0
RCU used illegally from extended quiescent state!
1 lock held by trinity-child1/18786:
#0: (rcu_read_lock){.+.+..}, at: [<ffffffff8113dd48>] __perf_event_overflow+0x108/0x310
stack backtrace:
CPU: 3 PID: 18786 Comm: trinity-child1 Not tainted 3.10.0-rc2+ #38
0000000000000000 ffff88020767bac8 ffffffff816e2f6b ffff88020767baf8
ffffffff810b5897 ffff88021de92520 0000000000000000 ffff88020767bbf8
0000000000000000 ffff88020767bb78 ffffffff8113ded4 ffffffff8113dd48
Call Trace:
[<ffffffff816e2f6b>] dump_stack+0x19/0x1b
[<ffffffff810b5897>] lockdep_rcu_suspicious+0xe7/0x120
[<ffffffff8113ded4>] __perf_event_overflow+0x294/0x310
[<ffffffff8113dd48>] ? __perf_event_overflow+0x108/0x310
[<ffffffff81309289>] ? __const_udelay+0x29/0x30
[<ffffffff81076054>] ? __rcu_read_unlock+0x54/0xa0
[<ffffffff816f4000>] ? ftrace_call+0x5/0x2f
[<ffffffff8113dfa1>] perf_swevent_overflow+0x51/0xe0
[<ffffffff8113e08f>] perf_swevent_event+0x5f/0x90
[<ffffffff8113e1c9>] perf_tp_event+0x109/0x4f0
[<ffffffff8113e36f>] ? perf_tp_event+0x2af/0x4f0
[<ffffffff81074630>] ? __rcu_read_lock+0x20/0x20
[<ffffffff8112d79f>] perf_ftrace_function_call+0xbf/0xd0
[<ffffffff8110e1e1>] ? ftrace_ops_control_func+0x181/0x210
[<ffffffff81074630>] ? __rcu_read_lock+0x20/0x20
[<ffffffff81100cae>] ? rcu_eqs_enter_common+0x5e/0x470
[<ffffffff8110e1e1>] ftrace_ops_control_func+0x181/0x210
[<ffffffff816f4000>] ftrace_call+0x5/0x2f
[<ffffffff8110e229>] ? ftrace_ops_control_func+0x1c9/0x210
[<ffffffff816f4000>] ? ftrace_call+0x5/0x2f
[<ffffffff81074635>] ? debug_lockdep_rcu_enabled+0x5/0x40
[<ffffffff81074635>] ? debug_lockdep_rcu_enabled+0x5/0x40
[<ffffffff81100cae>] ? rcu_eqs_enter_common+0x5e/0x470
[<ffffffff8110112a>] rcu_eqs_enter+0x6a/0xb0
[<ffffffff81103673>] rcu_user_enter+0x13/0x20
[<ffffffff8114541a>] user_enter+0x6a/0xd0
[<ffffffff8100f6d8>] syscall_trace_leave+0x78/0x140
[<ffffffff816f46af>] int_check_syscall_exit_work+0x34/0x3d
------------[ cut here ]------------
Perf uses rcu_read_lock() but as the function tracer can trace functions
even when RCU is not currently active, this makes the rcu_read_lock()
used by perf ineffective.
As perf is currently the only user of the ftrace_ops_control_func() and
perf is also the only function callback that actively uses rcu_read_lock(),
the quick fix is to prevent the ftrace_ops_control_func() from calling
its callbacks if RCU is not active.
With Paul's new "rcu_is_watching()" we can tell if RCU is active or not.
Reported-by: Dave Jones <davej@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Use rbtree_postorder_for_each_entry_safe() to destroy the rbtree instead
of opencoding an alternate postorder iteration that modifies the tree
Link: http://lkml.kernel.org/r/1383345566-25087-2-git-send-email-cody@linux.vnet.ibm.com
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The parser set up is just a generic utility that uses local variables
allocated by the function. There's no need to hold the graph_lock for
this set up.
This also makes the code simpler.
Link: http://lkml.kernel.org/r/1381739066-7531-4-git-send-email-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The struct ftrace_graph_data is for generalizing the access to
set_graph_function file. This is a preparation for adding support to
set_graph_notrace.
Link: http://lkml.kernel.org/r/1381739066-7531-3-git-send-email-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The ftrace_graph_filter_enabled means that user sets function filter
and it always has same meaning of ftrace_graph_count > 0.
Link: http://lkml.kernel.org/r/1381739066-7531-2-git-send-email-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Andrey reported the following report:
ERROR: AddressSanitizer: heap-buffer-overflow on address ffff8800359c99f3
ffff8800359c99f3 is located 0 bytes to the right of 243-byte region [ffff8800359c9900, ffff8800359c99f3)
Accessed by thread T13003:
#0 ffffffff810dd2da (asan_report_error+0x32a/0x440)
#1 ffffffff810dc6b0 (asan_check_region+0x30/0x40)
#2 ffffffff810dd4d3 (__tsan_write1+0x13/0x20)
#3 ffffffff811cd19e (ftrace_regex_release+0x1be/0x260)
#4 ffffffff812a1065 (__fput+0x155/0x360)
#5 ffffffff812a12de (____fput+0x1e/0x30)
#6 ffffffff8111708d (task_work_run+0x10d/0x140)
#7 ffffffff810ea043 (do_exit+0x433/0x11f0)
#8 ffffffff810eaee4 (do_group_exit+0x84/0x130)
#9 ffffffff810eafb1 (SyS_exit_group+0x21/0x30)
#10 ffffffff81928782 (system_call_fastpath+0x16/0x1b)
Allocated by thread T5167:
#0 ffffffff810dc778 (asan_slab_alloc+0x48/0xc0)
#1 ffffffff8128337c (__kmalloc+0xbc/0x500)
#2 ffffffff811d9d54 (trace_parser_get_init+0x34/0x90)
#3 ffffffff811cd7b3 (ftrace_regex_open+0x83/0x2e0)
#4 ffffffff811cda7d (ftrace_filter_open+0x2d/0x40)
#5 ffffffff8129b4ff (do_dentry_open+0x32f/0x430)
#6 ffffffff8129b668 (finish_open+0x68/0xa0)
#7 ffffffff812b66ac (do_last+0xb8c/0x1710)
#8 ffffffff812b7350 (path_openat+0x120/0xb50)
#9 ffffffff812b8884 (do_filp_open+0x54/0xb0)
#10 ffffffff8129d36c (do_sys_open+0x1ac/0x2c0)
#11 ffffffff8129d4b7 (SyS_open+0x37/0x50)
#12 ffffffff81928782 (system_call_fastpath+0x16/0x1b)
Shadow bytes around the buggy address:
ffff8800359c9700: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
ffff8800359c9780: fd fd fd fd fd fd fd fd fa fa fa fa fa fa fa fa
ffff8800359c9800: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
ffff8800359c9880: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
ffff8800359c9900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>ffff8800359c9980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00[03]fb
ffff8800359c9a00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
ffff8800359c9a80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
ffff8800359c9b00: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
ffff8800359c9b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8800359c9c00: 00 00 00 00 00 00 00 00 fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap redzone: fa
Heap kmalloc redzone: fb
Freed heap region: fd
Shadow gap: fe
The out-of-bounds access happens on 'parser->buffer[parser->idx] = 0;'
Although the crash happened in ftrace_regex_open() the real bug
occurred in trace_get_user() where there's an incrementation to
parser->idx without a check against the size. The way it is triggered
is if userspace sends in 128 characters (EVENT_BUF_SIZE + 1), the loop
that reads the last character stores it and then breaks out because
there is no more characters. Then the last character is read to determine
what to do next, and the index is incremented without checking size.
Then the caller of trace_get_user() usually nulls out the last character
with a zero, but since the index is equal to the size, it writes a nul
character after the allocated space, which can corrupt memory.
Luckily, only root user has write access to this file.
Link: http://lkml.kernel.org/r/20131009222323.04fd1a0d@gandalf.local.home
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The current "help" that comes out of the snapshot file when it is
not allocated looks like this:
# * Snapshot is freed *
#
# Snapshot commands:
# echo 0 > snapshot : Clears and frees snapshot buffer
# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.
# Takes a snapshot of the main buffer.
# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)
# (Doesn't have to be '2' works with any number that
# is not a '0' or '1')
Echo 2 says that it does not allocate the buffer, which is correct,
but to be more consistent with "echo 0" it should also state
that it does not free.
Link: http://lkml.kernel.org/r/20130914045916.GA4243@udknight
Signed-off-by: Wang YanQing <udknight@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
are still in flux, and will have to wait for 3.13.
The changes for 3.12 are mostly clean ups and minor fixes.
H. Peter Anvin added a check to x86_32 static function tracing that
helps a small segment of the kernel community.
Oleg Nesterov had a few changes from 3.11, but were mostly clean ups
and not worth pushing in the -rc time frame.
Li Zefan had small clean up with annotating a raw_init with __init.
I fixed a slight race in updating function callbacks, but the race
is so small and the bug that happens when it occurs is so minor it's
not even worth pushing to stable.
The only real enhancement is from Alexander Z Lam that made the
tracing_cpumask work for trace buffer instances, instead of them all
sharing a global cpumask.
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Merge tag 'trace-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"Not much changes for the 3.12 merge window. The major tracing changes
are still in flux, and will have to wait for 3.13.
The changes for 3.12 are mostly clean ups and minor fixes.
H Peter Anvin added a check to x86_32 static function tracing that
helps a small segment of the kernel community.
Oleg Nesterov had a few changes from 3.11, but were mostly clean ups
and not worth pushing in the -rc time frame.
Li Zefan had small clean up with annotating a raw_init with __init.
I fixed a slight race in updating function callbacks, but the race is
so small and the bug that happens when it occurs is so minor it's not
even worth pushing to stable.
The only real enhancement is from Alexander Z Lam that made the
tracing_cpumask work for trace buffer instances, instead of them all
sharing a global cpumask"
* tag 'trace-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace/rcu: Do not trace debug_lockdep_rcu_enabled()
x86-32, ftrace: Fix static ftrace when early microcode is enabled
ftrace: Fix a slight race in modifying what function callback gets traced
tracing: Make tracing_cpumask available for all instances
tracing: Kill the !CONFIG_MODULES code in trace_events.c
tracing: Don't pass file_operations array to event_create_dir()
tracing: Kill trace_create_file_ops() and friends
tracing/syscalls: Annotate raw_init function with __init
There's a slight race when going from a list function to a non list
function. That is, when only one callback is registered to the function
tracer, it gets called directly by the mcount trampoline. But if this
function has filters, it may be called by the wrong functions.
As the list ops callback that handles multiple callbacks that are
registered to ftrace, it also handles what functions they call. While
the transaction is taking place, use the list function always, and
after all the updates are finished (only the functions that should be
traced are being traced), then we can update the trampoline to call
the function directly.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Pull RCU updates from Paul E. McKenney:
"
* Update RCU documentation. These were posted to LKML at
https://lkml.org/lkml/2013/8/19/611.
* Miscellaneous fixes. These were posted to LKML at
https://lkml.org/lkml/2013/8/19/619.
* Full-system idle detection. This is for use by Frederic
Weisbecker's adaptive-ticks mechanism. Its purpose is
to allow the timekeeping CPU to shut off its tick when
all other CPUs are idle. These were posted to LKML at
https://lkml.org/lkml/2013/8/19/648.
* Improve rcutorture test coverage. These were posted to LKML at
https://lkml.org/lkml/2013/8/19/675.
"
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Allow tracer instances to disable tracing by cpu by moving
the static global tracing_cpumask into trace_array.
Link: http://lkml.kernel.org/r/921622317f239bfc2283cac2242647801ef584f2.1375980149.git.azl@google.com
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Signed-off-by: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Move trace_module_nb under CONFIG_MODULES and kill the dummy
trace_module_notify(). Imho it doesn't make sense to define
"struct notifier_block" and its .notifier_call just to avoid
"ifdef" in event_trace_init(), and all other !CONFIG_MODULES
code has already gone away.
Link: http://lkml.kernel.org/r/20130731173137.GA31043@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Now that event_create_dir() and __trace_add_new_event() always
use the same file_operations we can kill these arguments and
simplify the code.
Link: http://lkml.kernel.org/r/20130731173135.GA31040@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
trace_create_file_ops() allocates the copy of id/filter/format/enable
file_operations to set "f_op->owner = mod" for fops_get().
However after the recent changes there is no reason to prevent rmmod
even if one of these files is opened. A file operation can do nothing
but fail after remove_event_file_dir() clears ->i_private for every
file removed by trace_module_remove_events().
Kill "struct ftrace_module_file_ops" and fix the compilation errors.
Link: http://lkml.kernel.org/r/20130731173132.GA31033@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
init_syscall_trace() can only be called during kernel bootup only, so we can
mark it and the functions it calls as __init.
Link: http://lkml.kernel.org/r/51528E89.6080508@huawei.com
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Fixed two issues with changing the timestamp clock with trace_clock:
- The global buffer was reset on instance clock changes. Change this to pass
the correct per-instance buffer
- ftrace_now() is used to set buf->time_start in tracing_reset_online_cpus().
This was incorrect because ftrace_now() used the global buffer's clock to
return the current time. Change this to use buffer_ftrace_now() which
returns the current time for the correct per-instance buffer.
Also removed tracing_reset_current() because it is not used anywhere
Link: http://lkml.kernel.org/r/1375493777-17261-2-git-send-email-azl@google.com
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Releasing the free_buffer file in an instance causes the global buffer
to be stopped when TRACE_ITER_STOP_ON_FREE is enabled. Operate on the
correct buffer.
Link: http://lkml.kernel.org/r/1375493777-17261-1-git-send-email-azl@google.com
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
tracing_read_pipe zeros all fields bellow "seq". The declaration contains
a comment about that, but it doesn't help.
The first field is "snapshot", it's true when current open file is
snapshot. Looks obvious, that it should not be zeroed.
The second field is "started". It was converted from cpumask_t to
cpumask_var_t (v2.6.28-4983-g4462344), in other words it was
converted from cpumask to pointer on cpumask.
Currently the reference on "started" memory is lost after the first read
from tracing_read_pipe and a proper object will never be freed.
The "started" is never dereferenced for trace_pipe, because trace_pipe
can't have the TRACE_FILE_ANNOTATE options.
Link: http://lkml.kernel.org/r/1375463803-3085183-1-git-send-email-avagin@openvz.org
Cc: stable@vger.kernel.org # 2.6.30
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Uprobes suffer the same problem that kprobes have. There's a race between
writing to the "enable" file and removing the probe. The probe checks for
it being in use and if it is not, goes about deleting the probe and the
event that represents it. But the problem with that is, after it checks
if it is in use it can be enabled, and the deletion of the event (access
to the probe) will fail, as it is in use. But the uprobe will still be
deleted. This is a problem as the event can reference the uprobe that
was deleted.
The fix is to remove the event first, and check to make sure the event
removal succeeds. Then it is safe to remove the probe.
When the event exists, either ftrace or perf can enable the probe and
prevent the event from being removed.
Link: http://lkml.kernel.org/r/20130704034038.991525256@goodmis.org
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When a probe is being removed, it cleans up the event files that correspond
to the probe. But there is a race between writing to one of these files
and deleting the probe. This is especially true for the "enable" file.
CPU 0 CPU 1
----- -----
fd = open("enable",O_WRONLY);
probes_open()
release_all_trace_probes()
unregister_trace_probe()
if (trace_probe_is_enabled(tp))
return -EBUSY
write(fd, "1", 1)
__ftrace_set_clr_event()
call->class->reg()
(kprobe_register)
enable_trace_probe(tp)
__unregister_trace_probe(tp);
list_del(&tp->list)
unregister_probe_event(tp) <-- fails!
free_trace_probe(tp)
write(fd, "0", 1)
__ftrace_set_clr_event()
call->class->unreg
(kprobe_register)
disable_trace_probe(tp) <-- BOOM!
A test program was written that used two threads to simulate the
above scenario adding a nanosleep() interval to change the timings
and after several thousand runs, it was able to trigger this bug
and crash:
BUG: unable to handle kernel paging request at 00000005000000f9
IP: [<ffffffff810dee70>] probes_open+0x3b/0xa7
PGD 7808a067 PUD 0
Oops: 0000 [#1] PREEMPT SMP
Dumping ftrace buffer:
---------------------------------
Modules linked in: ipt_MASQUERADE sunrpc ip6t_REJECT nf_conntrack_ipv6
CPU: 1 PID: 2070 Comm: test-kprobe-rem Not tainted 3.11.0-rc3-test+ #47
Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS SDBLI944.86P 05/08/2007
task: ffff880077756440 ti: ffff880076e52000 task.ti: ffff880076e52000
RIP: 0010:[<ffffffff810dee70>] [<ffffffff810dee70>] probes_open+0x3b/0xa7
RSP: 0018:ffff880076e53c38 EFLAGS: 00010203
RAX: 0000000500000001 RBX: ffff88007844f440 RCX: 0000000000000003
RDX: 0000000000000003 RSI: 0000000000000003 RDI: ffff880076e52000
RBP: ffff880076e53c58 R08: ffff880076e53bd8 R09: 0000000000000000
R10: ffff880077756440 R11: 0000000000000006 R12: ffffffff810dee35
R13: ffff880079250418 R14: 0000000000000000 R15: ffff88007844f450
FS: 00007f87a276f700(0000) GS:ffff88007d480000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00000005000000f9 CR3: 0000000077262000 CR4: 00000000000007e0
Stack:
ffff880076e53c58 ffffffff81219ea0 ffff88007844f440 ffffffff810dee35
ffff880076e53ca8 ffffffff81130f78 ffff8800772986c0 ffff8800796f93a0
ffffffff81d1b5d8 ffff880076e53e04 0000000000000000 ffff88007844f440
Call Trace:
[<ffffffff81219ea0>] ? security_file_open+0x2c/0x30
[<ffffffff810dee35>] ? unregister_trace_probe+0x4b/0x4b
[<ffffffff81130f78>] do_dentry_open+0x162/0x226
[<ffffffff81131186>] finish_open+0x46/0x54
[<ffffffff8113f30b>] do_last+0x7f6/0x996
[<ffffffff8113cc6f>] ? inode_permission+0x42/0x44
[<ffffffff8113f6dd>] path_openat+0x232/0x496
[<ffffffff8113fc30>] do_filp_open+0x3a/0x8a
[<ffffffff8114ab32>] ? __alloc_fd+0x168/0x17a
[<ffffffff81131f4e>] do_sys_open+0x70/0x102
[<ffffffff8108f06e>] ? trace_hardirqs_on_caller+0x160/0x197
[<ffffffff81131ffe>] SyS_open+0x1e/0x20
[<ffffffff81522742>] system_call_fastpath+0x16/0x1b
Code: e5 41 54 53 48 89 f3 48 83 ec 10 48 23 56 78 48 39 c2 75 6c 31 f6 48 c7
RIP [<ffffffff810dee70>] probes_open+0x3b/0xa7
RSP <ffff880076e53c38>
CR2: 00000005000000f9
---[ end trace 35f17d68fc569897 ]---
The unregister_trace_probe() must be done first, and if it fails it must
fail the removal of the kprobe.
Several changes have already been made by Oleg Nesterov and Masami Hiramatsu
to allow moving the unregister_probe_event() before the removal of
the probe and exit the function if it fails. This prevents the tp
structure from being used after it is freed.
Link: http://lkml.kernel.org/r/20130704034038.819592356@goodmis.org
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The "break" used in the do_for_each_event_file() is used as an optimization
as the loop is really a double loop. The loop searches all event files
for each trace_array. There's only one matching event file per trace_array
and after we find the event file for the trace_array, the break is used
to jump to the next trace_array and start the search there.
As this is not a standard way of using "break" in C code, it requires
a comment right before the break to let people know what is going on.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
