The helper bpf_probe_read arg2 type is changed
from ARG_CONST_SIZE to ARG_CONST_SIZE_OR_ZERO to permit
size-0 buffer. Together with newer ARG_CONST_SIZE_OR_ZERO
semantics which allows non-NULL buffer with size 0,
this allows simpler bpf programs with verifier acceptance.
The previous commit which changes ARG_CONST_SIZE_OR_ZERO semantics
has details on examples.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull scheduler updates from Ingo Molnar:
"The main updates in this cycle were:
- Group balancing enhancements and cleanups (Brendan Jackman)
- Move CPU isolation related functionality into its separate
kernel/sched/isolation.c file, with related 'housekeeping_*()'
namespace and nomenclature et al. (Frederic Weisbecker)
- Improve the interactive/cpu-intense fairness calculation (Josef
Bacik)
- Improve the PELT code and related cleanups (Peter Zijlstra)
- Improve the logic of pick_next_task_fair() (Uladzislau Rezki)
- Improve the RT IPI based balancing logic (Steven Rostedt)
- Various micro-optimizations:
- better !CONFIG_SCHED_DEBUG optimizations (Patrick Bellasi)
- better idle loop (Cheng Jian)
- ... plus misc fixes, cleanups and updates"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits)
sched/core: Optimize sched_feat() for !CONFIG_SCHED_DEBUG builds
sched/sysctl: Fix attributes of some extern declarations
sched/isolation: Document isolcpus= boot parameter flags, mark it deprecated
sched/isolation: Add basic isolcpus flags
sched/isolation: Move isolcpus= handling to the housekeeping code
sched/isolation: Handle the nohz_full= parameter
sched/isolation: Introduce housekeeping flags
sched/isolation: Split out new CONFIG_CPU_ISOLATION=y config from CONFIG_NO_HZ_FULL
sched/isolation: Rename is_housekeeping_cpu() to housekeeping_cpu()
sched/isolation: Use its own static key
sched/isolation: Make the housekeeping cpumask private
sched/isolation: Provide a dynamic off-case to housekeeping_any_cpu()
sched/isolation, watchdog: Use housekeeping_cpumask() instead of ad-hoc version
sched/isolation: Move housekeeping related code to its own file
sched/idle: Micro-optimize the idle loop
sched/isolcpus: Fix "isolcpus=" boot parameter handling when !CONFIG_CPUMASK_OFFSTACK
x86/tsc: Append the 'tsc=' description for the 'tsc=unstable' boot parameter
sched/rt: Simplify the IPI based RT balancing logic
block/ioprio: Use a helper to check for RT prio
sched/rt: Add a helper to test for a RT task
...
Pull perf updates from Ingo Molnar:
"The main changes in this cycle were:
Kernel:
- kprobes updates: use better W^X patterns for code modifications,
improve optprobes, remove jprobes. (Masami Hiramatsu, Kees Cook)
- core fixes: event timekeeping (enabled/running times statistics)
fixes, perf_event_read() locking fixes and cleanups, etc. (Peter
Zijlstra)
- Extend x86 Intel free-running PEBS support and support x86
user-register sampling in perf record and perf script. (Andi Kleen)
Tooling:
- Completely rework the way inline frames are handled. Instead of
querying for the inline nodes on-demand in the individual tools, we
now create proper callchain nodes for inlined frames. (Milian
Wolff)
- 'perf trace' updates (Arnaldo Carvalho de Melo)
- Implement a way to print formatted output to per-event files in
'perf script' to facilitate generate flamegraphs, elliminating the
need to write scripts to do that separation (yuzhoujian, Arnaldo
Carvalho de Melo)
- Update vendor events JSON metrics for Intel's Broadwell, Broadwell
Server, Haswell, Haswell Server, IvyBridge, IvyTown, JakeTown,
Sandy Bridge, Skylake, SkyLake Server - and Goldmont Plus V1 (Andi
Kleen, Kan Liang)
- Multithread the synthesizing of PERF_RECORD_ events for
pre-existing threads in 'perf top', speeding up that phase, greatly
improving the user experience in systems such as Intel's Knights
Mill (Kan Liang)
- Introduce the concept of weak groups in 'perf stat': try to set up
a group, but if it's not schedulable fallback to not using a group.
That gives us the best of both worlds: groups if they work, but
still a usable fallback if they don't. E.g: (Andi Kleen)
- perf sched timehist enhancements (David Ahern)
- ... various other enhancements, updates, cleanups and fixes"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (139 commits)
kprobes: Don't spam the build log with deprecation warnings
arm/kprobes: Remove jprobe test case
arm/kprobes: Fix kretprobe test to check correct counter
perf srcline: Show correct function name for srcline of callchains
perf srcline: Fix memory leak in addr2inlines()
perf trace beauty kcmp: Beautify arguments
perf trace beauty: Implement pid_fd beautifier
tools include uapi: Grab a copy of linux/kcmp.h
perf callchain: Fix double mapping al->addr for children without self period
perf stat: Make --per-thread update shadow stats to show metrics
perf stat: Move the shadow stats scale computation in perf_stat__update_shadow_stats
perf tools: Add perf_data_file__write function
perf tools: Add struct perf_data_file
perf tools: Rename struct perf_data_file to perf_data
perf script: Print information about per-event-dump files
perf trace beauty prctl: Generate 'option' string table from kernel headers
tools include uapi: Grab a copy of linux/prctl.h
perf script: Allow creating per-event dump files
perf evsel: Restore evsel->priv as a tool private area
perf script: Use event_format__fprintf()
...
Error injection is sloppy and very ad-hoc. BPF could fill this niche
perfectly with it's kprobe functionality. We could make sure errors are
only triggered in specific call chains that we care about with very
specific situations. Accomplish this with the bpf_override_funciton
helper. This will modify the probe'd callers return value to the
specified value and set the PC to an override function that simply
returns, bypassing the originally probed function. This gives us a nice
clean way to implement systematic error injection for all of our code
paths.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
sg.c calls into the blktrace functions without holding the proper queue
mutex for doing setup, start/stop, or teardown.
Add internal unlocked variants, and export the ones that do the proper
locking.
Fixes: 6da127ad09 ("blktrace: Add blktrace ioctls to SCSI generic devices")
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Files removed in 'net-next' had their license header updated
in 'net'. We take the remove from 'net-next'.
Signed-off-by: David S. Miller <davem@davemloft.net>
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
During perf event attaching/detaching bpf programs,
the tp_event->prog_array change is protected by the
bpf_event_mutex lock in both attaching and deteching
functions. Although tp_event->prog_array is a rcu
pointer, rcu_derefrence is not needed to access it
since mutex lock will guarantee ordering.
Verified through "make C=2" that sparse
locking check still happy with the new change.
Also change the label name in perf_event_{attach,detach}_bpf_prog
from "out" to "unlock" to reflect the code action after the label.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
commit afdb09c720 ("security: bpf: Add LSM hooks for bpf object related
syscall") included linux/bpf.h in linux/security.h. As a result, bpf
programs including bpf_helpers.h and some other header that ends up
pulling in also security.h, such as several examples under samples/bpf,
fail to compile because bpf_tail_call and bpf_get_stackid are now
"redefined as different kind of symbol".
>From bpf.h:
u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5);
u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
Whereas in bpf_helpers.h they are:
static void (*bpf_tail_call)(void *ctx, void *map, int index);
static int (*bpf_get_stackid)(void *ctx, void *map, int flags);
Fix this by removing the unused declaration of bpf_tail_call and moving
the declaration of bpf_get_stackid in bpf_trace.c, which is the only
place where it's needed.
Signed-off-by: Gianluca Borello <g.borello@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
eBPF programs would like access to the (perf) event enabled and
running times along with the event value, such that they can deal with
event multiplexing (among other things).
This patch extends the interface; a future eBPF patch will utilize
the new functionality.
[ Note, there's a same-content commit with a poor changelog and a meaningless
title in the networking tree as well - but we need this change for subsequent
perf work, so apply it here as well, with a proper changelog. Hopefully Git
will be able to sort out this somewhat messy workflow, if there are no other,
conflicting changes to these files. ]
Signed-off-by: Yonghong Song <yhs@fb.com>
[ Rewrote the changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <ast@fb.com>
Cc: <daniel@iogearbox.net>
Cc: <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: David S. Miller <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20171005161923.332790-2-yhs@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.
However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:
----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()
// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch
virtual patch
@ depends on patch @
expression E1, E2;
@@
- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)
@ depends on patch @
expression E;
@@
- ACCESS_ONCE(E)
+ READ_ONCE(E)
----
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch enables multiple bpf attachments for a
kprobe/uprobe/tracepoint single trace event.
Each trace_event keeps a list of attached perf events.
When an event happens, all attached bpf programs will
be executed based on the order of attachment.
A global bpf_event_mutex lock is introduced to protect
prog_array attaching and detaching. An alternative will
be introduce a mutex lock in every trace_event_call
structure, but it takes a lot of extra memory.
So a global bpf_event_mutex lock is a good compromise.
The bpf prog detachment involves allocation of memory.
If the allocation fails, a dummy do-nothing program
will replace to-be-detached program in-place.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
struct bpf_verifier_ops contains both verifier ops and operations
used later during program's lifetime (test_run). Split the runtime
ops into a different structure.
BPF_PROG_TYPE() will now append ## _prog_ops or ## _verifier_ops
to the names.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The function-trace <-> perf interface is a tad messed up. Where all
the other trace <-> perf interfaces use a single trace hook
registration and use per-cpu RCU based hlist to iterate the events,
function-trace actually needs multiple hook registrations in order to
minimize function entry patching when filters are present.
The end result is that we iterate events both on the trace hook and on
the hlist, which results in reporting events multiple times.
Since function-trace cannot use the regular scheme, fix it the other
way around, use singleton hlists.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Revert commit:
75e8387685 ("perf/ftrace: Fix double traces of perf on ftrace:function")
The reason I instantly stumbled on that patch is that it only addresses the
ftrace situation and doesn't mention the other _5_ places that use this
interface. It doesn't explain why those don't have the problem and if not, why
their solution doesn't work for ftrace.
It doesn't, but this is just putting more duct tape on.
Link: http://lkml.kernel.org/r/20171011080224.200565770@infradead.org
Cc: Zhou Chengming <zhouchengming1@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
After trace_selftest_startup_sched_switch is removed, trace_test_buffer()
is only used sometimes, leading to this warning:
kernel/trace/trace_selftest.c:62:12: error: 'trace_test_buffer' defined but not used [-Werror=unused-function]
There is no simple #ifdef condition that captures well whether the
function is in fact used or not, so marking it as __maybe_unused is
probably the best way to shut up the warning. The function will then
be silently dropped when there is no user.
Link: http://lkml.kernel.org/r/20171013142227.1273469-1-arnd@arndb.de
Fixes: d8c4deee6d ("tracing: Remove obsolete sched_switch tracer selftest")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Filters should be cleared of init functions during freeing of init
memory when the ftrace dyn records are released. However in current
code, the filters are left as is. This patch clears the hashes of the
saved init functions when the init memory is freed. This fixes the
following issue reproducible with the following sequence of commands for
a test module:
================================================
void bar(void)
{
printk(KERN_INFO "bar!\n");
}
void foo(void)
{
printk(KERN_INFO "foo!\n");
bar();
}
static int __init hello_init(void)
{
printk(KERN_INFO "Hello world!\n");
foo();
return 0;
}
static void __exit hello_cleanup(void)
{
printk(KERN_INFO "Cleaning up module.\n");
}
module_init(hello_init);
module_exit(hello_cleanup);
================================================
Commands:
echo '*:mod:test' > /d/tracing/set_ftrace_filter
echo function > /d/tracing/current_tracer
modprobe test
rmmod test
sleep 1
modprobe test
cat /d/tracing/set_ftrace_filter
Behavior without patch: Init function is still in the filter
Expected behavior: Shouldn't have any of the filters set
Link: http://lkml.kernel.org/r/20171009192931.56401-1-joelaf@google.com
Signed-off-by: Joel Fernandes <joelaf@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This patch adds helper bpf_perf_prog_read_cvalue for perf event based bpf
programs, to read event counter and enabled/running time.
The enabled/running time is accumulated since the perf event open.
The typical use case for perf event based bpf program is to attach itself
to a single event. In such cases, if it is desirable to get scaling factor
between two bpf invocations, users can can save the time values in a map,
and use the value from the map and the current value to calculate
the scaling factor.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Hardware pmu counters are limited resources. When there are more
pmu based perf events opened than available counters, kernel will
multiplex these events so each event gets certain percentage
(but not 100%) of the pmu time. In case that multiplexing happens,
the number of samples or counter value will not reflect the
case compared to no multiplexing. This makes comparison between
different runs difficult.
Typically, the number of samples or counter value should be
normalized before comparing to other experiments. The typical
normalization is done like:
normalized_num_samples = num_samples * time_enabled / time_running
normalized_counter_value = counter_value * time_enabled / time_running
where time_enabled is the time enabled for event and time_running is
the time running for event since last normalization.
This patch adds helper bpf_perf_event_read_value for kprobed based perf
event array map, to read perf counter and enabled/running time.
The enabled/running time is accumulated since the perf event open.
To achieve scaling factor between two bpf invocations, users
can can use cpu_id as the key (which is typical for perf array usage model)
to remember the previous value and do the calculation inside the
bpf program.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch does not impact existing functionalities.
It contains the changes in perf event area needed for
subsequent bpf_perf_event_read_value and
bpf_perf_prog_read_value helpers.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
If a module is loaded while tracing is enabled, then there's a possibility
that the module init functions were traced. These functions have their name
and address stored by ftrace such that it can translate the function address
that is written into the buffer into a human readable function name.
As userspace tools may be doing the same, they need a way to map function
names to their address as well. This is done through reading /proc/kallsyms.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The ftrace_mod_map is a descriptor to save module init function names in
case they were traced, and the trace output needs to reference the function
name from the function address. But after the function is unloaded, it
the maps should be freed, as the rest of the function names are as well.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Allow for module init sections to be traced as well as core kernel init
sections. Now that filtering modules functions can be stored, for when they
are loaded, it makes sense to be able to trace them.
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
In order to be able to trace module init functions, the module code needs to
tell ftrace what is being freed when the init sections are freed. Use the
code that the main init calls to tell ftrace to free the main init sections.
This requires passing in a start and end address to free.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
log2 as currently implemented applies only to u64 trace_event_field
derived fields, and assumes that anything it's applied to is a u64
field.
To prepare for synthetic fields like latencies, log2 should be
applicable to those as well, so take the opportunity now to fix the
current problems as well as expand to more general uses.
log2 should be thought of as a chaining function rather than a field
type. To enable this as well as possible future function
implementations, add a hist_field operand array into the hist_field
definition for this purpose, and make use of it to implement the log2
'function'.
Link: http://lkml.kernel.org/r/b47f93fc0b87b36eccf716b0c018f3a71e1f1111.1506105045.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
traceprobe_probes_write() and traceprobe_command() actually contain
nothing that ties them to kprobes - the code is generically useful for
similar types of parsing elsewhere, so separate it out and move it to
trace.c/trace.h.
Other than moving it, the only change is in naming:
traceprobe_probes_write() becomes trace_parse_run_command() and
traceprobe_command() becomes trace_run_command().
Link: http://lkml.kernel.org/r/ae5c26ea40c196a8986854d921eb6e713ede7e3f.1506105045.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The current method to prevent the ring buffer from entering into a recursize
loop is to use a bitmask and set the bit that maps to the current context
(normal, softirq, irq or NMI), and if that bit was already set, it is
considered a recursive loop.
New code is being added that may require the ring buffer to be entered a
second time in the current context. The recursive locking prevents that from
happening. Instead of mapping a bitmask to the current context, just allow 4
levels of nesting in the ring buffer. This matches the 4 context levels that
it can already nest. It is highly unlikely to have more than two levels,
thus it should be fine when we add the second entry into the ring buffer. If
that proves to be a problem, we can always up the number to 8.
An added benefit is that reading preempt_count() to get the current level
adds a very slight but noticeable overhead. This removes that need.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
In order to make future changes where we need to call
tracing_set_clock() from within an event command, the order of
trace_types_lock and event_mutex must be reversed, as the event command
will hold event_mutex and the trace_types_lock is taken from within
tracing_set_clock().
Link: http://lkml.kernel.org/r/20170921162249.0dde3dca@gandalf.local.home
Requested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pull tracing fixlets from Steven Rostedt:
"Two updates:
- A memory fix with left over code from spliting out ftrace_ops and
function graph tracer, where the function graph tracer could reset
the trampoline pointer, leaving the old trampoline not to be freed
(memory leak).
- The update to Paul's patch that added the unnecessary READ_ONCE().
This removes the unnecessary READ_ONCE() instead of having to
rebase the branch to update the patch that added it"
* tag 'trace-v4.14-rc1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
rcu: Remove extraneous READ_ONCE()s from rcu_irq_{enter,exit}()
ftrace: Fix kmemleak in unregister_ftrace_graph
The trampoline allocated by function tracer was overwriten by function_graph
tracer, and caused a memory leak. The save_global_trampoline should have
saved the previous trampoline in register_ftrace_graph() and restored it in
unregister_ftrace_graph(). But as it is implemented, save_global_trampoline was
only used in unregister_ftrace_graph as default value 0, and it overwrote the
previous trampoline's value. Causing the previous allocated trampoline to be
lost.
kmmeleak backtrace:
kmemleak_vmalloc+0x77/0xc0
__vmalloc_node_range+0x1b5/0x2c0
module_alloc+0x7c/0xd0
arch_ftrace_update_trampoline+0xb5/0x290
ftrace_startup+0x78/0x210
register_ftrace_function+0x8b/0xd0
function_trace_init+0x4f/0x80
tracing_set_tracer+0xe6/0x170
tracing_set_trace_write+0x90/0xd0
__vfs_write+0x37/0x170
vfs_write+0xb2/0x1b0
SyS_write+0x55/0xc0
do_syscall_64+0x67/0x180
return_from_SYSCALL_64+0x0/0x6a
[
Looking further into this, I found that this was left over from when the
function and function graph tracers shared the same ftrace_ops. But in
commit 5f151b2401 ("ftrace: Fix function_profiler and function tracer
together"), the two were separated, and the save_global_trampoline no
longer was necessary (and it may have been broken back then too).
-- Steven Rostedt
]
Link: http://lkml.kernel.org/r/20170912021454.5976-1-shuwang@redhat.com
Cc: stable@vger.kernel.org
Fixes: 5f151b2401 ("ftrace: Fix function_profiler and function tracer together")
Signed-off-by: Shu Wang <shuwang@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
