Currently, the notification of a new max latency is sent from
timerlat's IRQ handler anytime a new max latency is found.
While this behavior is not wrong, the send IPI overhead itself
will increase the thread latency and that is not the desired
effect (tracing overhead).
Moreover, the thread will notify a new max latency again because
the thread latency as it is always higher than the IRQ latency
that woke it up.
The only case in which it is helpful to notify a new max latency
from IRQ is when stop tracing (for the IRQ) is set, as in this
case, the thread will not be dispatched.
Notify a new max latency from the IRQ handler only if stop tracing is
set for the IRQ handler.
Link: https://lkml.kernel.org/r/2c2d9a56c0886c8402ba320de32856cbbb10c2bb.1652175637.git.bristot@kernel.org
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Reported-by: Clark Williams <williams@redhat.com>
Fixes: a955d7eac1 ("trace: Add timerlat tracer")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Max Filippov reported:
When building kernel with CONFIG_KRETPROBES=n kernel/kprobes.c
compilation fails with the following messages:
kernel/kprobes.c: In function ‘recycle_rp_inst’:
kernel/kprobes.c:1273:32: error: implicit declaration of function
‘get_kretprobe’
kernel/kprobes.c: In function ‘kprobe_flush_task’:
kernel/kprobes.c:1299:35: error: ‘struct task_struct’ has no member
named ‘kretprobe_instances’
This came from the commit d741bf41d7 ("kprobes: Remove
kretprobe hash") which introduced get_kretprobe() and
kretprobe_instances member in task_struct when CONFIG_KRETPROBES=y,
but did not make recycle_rp_inst() and kprobe_flush_task()
depending on CONFIG_KRETPORBES.
Since those functions are only used for kretprobe, move those
functions into #ifdef CONFIG_KRETPROBE area.
Link: https://lkml.kernel.org/r/165163539094.74407.3838114721073251225.stgit@devnote2
Reported-by: Max Filippov <jcmvbkbc@gmail.com>
Fixes: d741bf41d7 ("kprobes: Remove kretprobe hash")
Cc: "Naveen N . Rao" <naveen.n.rao@linux.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S . Miller" <davem@davemloft.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Setting set_event_pid with trailing whitespace lead to endless write
system calls like below.
$ strace echo "123 " > /sys/kernel/debug/tracing/set_event_pid
execve("/usr/bin/echo", ["echo", "123 "], ...) = 0
...
write(1, "123 \n", 5) = 4
write(1, "\n", 1) = 0
write(1, "\n", 1) = 0
write(1, "\n", 1) = 0
write(1, "\n", 1) = 0
write(1, "\n", 1) = 0
....
This is because, the result of trace_get_user's are not returned when it
read at least one pid. To fix it, update read variable even if
parser->idx == 0.
The result of applied patch is below.
$ strace echo "123 " > /sys/kernel/debug/tracing/set_event_pid
execve("/usr/bin/echo", ["echo", "123 "], ...) = 0
...
write(1, "123 \n", 5) = 5
close(1) = 0
Link: https://lkml.kernel.org/r/20220503050546.288911-1-vvghjk1234@gmail.com
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Baik Song An <bsahn@etri.re.kr>
Cc: Hong Yeon Kim <kimhy@etri.re.kr>
Cc: Taeung Song <taeung@reallinux.co.kr>
Cc: linuxgeek@linuxgeek.io
Cc: stable@vger.kernel.org
Fixes: 4909010788 ("tracing: Add set_event_pid directory for future use")
Signed-off-by: Wonhyuk Yang <vvghjk1234@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
In create_var_ref(), init_var_ref() is called to initialize the fields
of variable ref_field, which is allocated in the previous function call
to create_hist_field(). Function init_var_ref() allocates the
corresponding fields such as ref_field->system, but frees these fields
when the function encounters an error. The caller later calls
destroy_hist_field() to conduct error handling, which frees the fields
and the variable itself. This results in double free of the fields which
are already freed in the previous function.
Fix this by storing NULL to the corresponding fields when they are freed
in init_var_ref().
Link: https://lkml.kernel.org/r/20220425063739.3859998-1-keitasuzuki.park@sslab.ics.keio.ac.jp
Fixes: 067fe038e7 ("tracing: Add variable reference handling to hist triggers")
CC: stable@vger.kernel.org
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Keita Suzuki <keitasuzuki.park@sslab.ics.keio.ac.jp>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The tracing_set_trace_write() function just removes the trailing whitespace
from the user supplied tracer name, but the leading whitespace should also
be removed.
In addition, if the user supplied tracer name contains only a few
whitespace characters, the first one will not be removed using the current
method, which results it a single whitespace character left in the buf.
To fix all of these issues, we use strim() to correctly remove both the
leading and trailing whitespace.
Link: https://lkml.kernel.org/r/20220121095623.1826679-1-ytcoode@gmail.com
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The print fmt check against trace events to make sure that the format does
not use pointers that may be freed from the time of the trace to the time
the event is read, gives a false positive on %pISpc when reading data that
was saved in __get_dynamic_array() when it is perfectly fine to do so, as
the data being read is on the ring buffer.
Link: https://lore.kernel.org/all/20220407144524.2a592ed6@canb.auug.org.au/
Cc: stable@vger.kernel.org
Fixes: 5013f454a3 ("tracing: Add check of trace event print fmts for dereferencing pointers")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When the new logic was made to handle deltas of events from interrupts
that interrupted other events, it required 64 bit local atomics.
Unfortunately, 64 bit local atomics are expensive on 32 bit architectures.
Thus, commit 10464b4aa6 ("ring-buffer: Add rb_time_t 64 bit operations
for speeding up 32 bit") created a type of seq lock timer for 32 bits.
It used two 32 bit local atomics, but required 2 bits from them each for
synchronization, making it only 60 bits.
Add a new "msb" field to hold the extra 4 bits that are cut off.
Link: https://lore.kernel.org/all/20220426175338.3807ca4f@gandalf.local.home/
Link: https://lkml.kernel.org/r/20220427170812.53cc7139@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
There's an absolute timestamp event in the ring buffer, but this only
saves 59 bits of the timestamp, as the 5 MSB is used for meta data
(stating it is an absolute time stamp). This was never an issue as all the
clocks currently in use never used those 5 MSB. But now there's a new
clock (TAI) that does.
To handle this case, when reading an absolute timestamp, a previous full
timestamp is passed in, and the 5 MSB of that timestamp is OR'd to the
absolute timestamp (if any of the 5 MSB are set), and then to test for
overflow, if the new result is smaller than the passed in previous
timestamp, then 1 << 59 is added to it.
All the extra processing is done on the reader "slow" path, with the
exception of the "too big delta" check, and the reading of timestamps
for histograms.
Note, libtraceevent will need to be updated to handle this case as well.
But this is not a user space regression, as user space was never able to
handle any timestamps that used more than 59 bits.
Link: https://lore.kernel.org/all/20220426175338.3807ca4f@gandalf.local.home/
Link: https://lkml.kernel.org/r/20220427153339.16c33f75@gandalf.local.home
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
To prepare for support asynchronous tracer_init_tracefs initcall,
avoid calling create_trace_option_files before __update_tracer_options.
Otherwise, create_trace_option_files will show warning because
some tracers in trace_types list are already in tr->topts.
For example, hwlat_tracer call register_tracer in late_initcall,
and global_trace.dir is already created in tracing_init_dentry,
hwlat_tracer will be put into tr->topts.
Then if the __update_tracer_options is executed after hwlat_tracer
registered, create_trace_option_files find that hwlat_tracer is
already in tr->topts.
Link: https://lkml.kernel.org/r/20220426122407.17042-2-mark-pk.tsai@mediatek.com
Link: https://lore.kernel.org/lkml/20220322133339.GA32582@xsang-OptiPlex-9020/
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When setting bootparams="trace_event=initcall:initcall_start tp_printk=1" in the
cmdline, the output_printk() was called, and the spin_lock_irqsave() was called in the
atomic and irq disable interrupt context suitation. On the PREEMPT_RT kernel,
these locks are replaced with sleepable rt-spinlock, so the stack calltrace will
be triggered.
Fix it by raw_spin_lock_irqsave when PREEMPT_RT and "trace_event=initcall:initcall_start
tp_printk=1" enabled.
BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0
preempt_count: 2, expected: 0
RCU nest depth: 0, expected: 0
Preemption disabled at:
[<ffffffff8992303e>] try_to_wake_up+0x7e/0xba0
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.17.1-rt17+ #19 34c5812404187a875f32bee7977f7367f9679ea7
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x60/0x8c
dump_stack+0x10/0x12
__might_resched.cold+0x11d/0x155
rt_spin_lock+0x40/0x70
trace_event_buffer_commit+0x2fa/0x4c0
? map_vsyscall+0x93/0x93
trace_event_raw_event_initcall_start+0xbe/0x110
? perf_trace_initcall_finish+0x210/0x210
? probe_sched_wakeup+0x34/0x40
? ttwu_do_wakeup+0xda/0x310
? trace_hardirqs_on+0x35/0x170
? map_vsyscall+0x93/0x93
do_one_initcall+0x217/0x3c0
? trace_event_raw_event_initcall_level+0x170/0x170
? push_cpu_stop+0x400/0x400
? cblist_init_generic+0x241/0x290
kernel_init_freeable+0x1ac/0x347
? _raw_spin_unlock_irq+0x65/0x80
? rest_init+0xf0/0xf0
kernel_init+0x1e/0x150
ret_from_fork+0x22/0x30
</TASK>
Link: https://lkml.kernel.org/r/20220419013910.894370-1-jun.miao@intel.com
Signed-off-by: Jun Miao <jun.miao@intel.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Currently the tp_printk option has no effect on syscall tracepoint.
When adding the kernel option parameter tp_printk, then:
echo 1 > /sys/kernel/debug/tracing/events/syscalls/enable
When running any application, no trace information is printed on the
terminal.
Now added printk for syscall tracepoints.
Link: https://lkml.kernel.org/r/20220410145025.681144-1-xiehuan09@gmail.com
Signed-off-by: Jeff Xie <xiehuan09@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Add the description of @n_sort_keys and make @sort_key ->
@sort_keys in tracing_map_sort_entries() kernel-doc comment
to remove warnings found by running scripts/kernel-doc, which
is caused by using 'make W=1'.
kernel/trace/tracing_map.c:1073: warning: Function parameter or member
'sort_keys' not described in 'tracing_map_sort_entries'
kernel/trace/tracing_map.c:1073: warning: Function parameter or member
'n_sort_keys' not described in 'tracing_map_sort_entries'
kernel/trace/tracing_map.c:1073: warning: Excess function parameter
'sort_key' description in 'tracing_map_sort_entries'
Link: https://lkml.kernel.org/r/20220402072015.45864-1-yang.lee@linux.alibaba.com
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Most architectures have ftrace related stuff in arch/*/kernel/ftrace.c
but powerpc has it spread in multiple files located in
arch/powerpc/kernel/trace/
In several architectures, there are also additional files containing
'ftrace' as part of the name but with some prefix or suffix.
Use wildcards to enlarge coverage.
With arch/*/*/*/*ftrace*:
arch/alpha/include/asm/ftrace.h
arch/arm64/include/asm/ftrace.h
arch/arm/include/asm/ftrace.h
arch/csky/include/asm/ftrace.h
arch/csky/kernel/probes/ftrace.c
arch/ia64/include/asm/ftrace.h
arch/m68k/include/asm/ftrace.h
arch/microblaze/include/asm/ftrace.h
arch/mips/include/asm/ftrace.h
arch/nds32/include/asm/ftrace.h
arch/parisc/include/asm/ftrace.h
arch/powerpc/include/asm/ftrace.h
arch/powerpc/kernel/trace/ftrace_64_pg.S
arch/powerpc/kernel/trace/ftrace.c
arch/powerpc/kernel/trace/ftrace_low.S
arch/powerpc/kernel/trace/ftrace_mprofile.S
arch/riscv/include/asm/ftrace.h
arch/riscv/kernel/probes/ftrace.c
arch/s390/include/asm/ftrace.h
arch/s390/include/asm/ftrace.lds.h
arch/sh/include/asm/ftrace.h
arch/sparc/include/asm/ftrace.h
arch/x86/include/asm/ftrace.h
arch/x86/kernel/kprobes/ftrace.c
arch/xtensa/include/asm/ftrace.h
With arch/*/*/*ftrace*:
arch/arm64/kernel/entry-ftrace.S
arch/arm64/kernel/ftrace.c
arch/arm/kernel/entry-ftrace.S
arch/arm/kernel/ftrace.c
arch/csky/kernel/ftrace.c
arch/ia64/kernel/ftrace.c
arch/microblaze/kernel/ftrace.c
arch/mips/kernel/ftrace.c
arch/nds32/kernel/ftrace.c
arch/parisc/kernel/ftrace.c
arch/powerpc/kernel/kprobes-ftrace.c
arch/riscv/kernel/ftrace.c
arch/s390/kernel/ftrace.c
arch/s390/kernel/ftrace.h
arch/sh/kernel/ftrace.c
arch/sparc/kernel/ftrace.c
arch/x86/kernel/ftrace_32.S
arch/x86/kernel/ftrace_64.S
arch/x86/kernel/ftrace.c
Link: https://lkml.kernel.org/r/e8338c0ad0e73991cbd8f31c215b16ea4efe212d.1648189904.git.christophe.leroy@csgroup.eu
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Code for registering triggers assumes it's possible to register more
than one trigger at a time. In fact, it's unimplemented and there
doesn't seem to be a reason to do that.
Remove the n_registered param from event_trigger_register() and fix up
callers.
Doing so simplifies the logic in event_trigger_register to the point
that it just becomes a wrapper calling event_command.reg().
It also removes the problematic call to event_command.unreg() in case
of failure. A new function, event_trigger_unregister() is also added
for callers to call themselves.
The changes to trace_events_hist.c simply allow compilation; a
separate patch follows which updates the hist triggers to work
correctly with the new changes.
Link: https://lkml.kernel.org/r/6149fec7a139d93e84fa4535672fb5bef88006b0.1644010575.git.zanussi@kernel.org
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Introduce fast/NMI safe accessor to clock tai for tracing. The Linux kernel
tracing infrastructure has support for using different clocks to generate
timestamps for trace events. Especially in TSN networks it's useful to have TAI
as trace clock, because the application scheduling is done in accordance to the
network time, which is based on TAI. With a tai trace_clock in place, it becomes
very convenient to correlate network activity with Linux kernel application
traces.
Use the same implementation as ktime_get_boot_fast_ns() does by reading the
monotonic time and adding the TAI offset. The same limitations as for the fast
boot implementation apply. The TAI offset may change at run time e.g., by
setting the time or using adjtimex() with an offset. However, these kind of
offset changes are rare events. Nevertheless, the user has to be aware and deal
with it in post processing.
An alternative approach would be to use the same implementation as
ktime_get_real_fast_ns() does. However, this requires to add an additional u64
member to the tk_read_base struct. This struct together with a seqcount is
designed to fit into a single cache line on 64 bit architectures. Adding a new
member would violate this constraint.
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20220414091805.89667-2-kurt@linutronix.de
Pull serial driver fix from Greg KH:
"This is a single serial driver fix for a build issue that showed up
due to changes that came in through the tty tree in 5.18-rc1 that were
missed previously. It resolves a build error with the mpc52xx_uart
driver.
It has been in linux-next this week with no reported problems"
* tag 'tty-5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
tty: serial: mpc52xx_uart: make rx/tx hooks return unsigned, part II.
Pull staging driver fix from Greg KH:
"Here is a single staging driver fix for 5.18-rc2 that resolves an
endian issue for the r8188eu driver. It has been in linux-next all
this week with no reported problems"
* tag 'staging-5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
staging: r8188eu: Fix PPPoE tag insertion on little endian systems
Pull driver core updates from Greg KH:
"Here are two small driver core changes for 5.18-rc2.
They are the final bits in the removal of the default_attrs field in
struct kobj_type. I had to wait until after 5.18-rc1 for all of the
changes to do this came in through different development trees, and
then one new user snuck in. So this series has two changes:
- removal of the default_attrs field in the powerpc/pseries/vas code.
The change has been acked by the PPC maintainers to come through
this tree
- removal of default_attrs from struct kobj_type now that all
in-kernel users are removed.
This cleans up the kobject code a little bit and removes some
duplicated functionality that confused people (now there is only
one way to do default groups)
Both of these have been in linux-next for all of this week with no
reported problems"
* tag 'driver-core-5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
kobject: kobj_type: remove default_attrs
powerpc/pseries/vas: use default_groups in kobj_type
Pull char/misc driver fix from Greg KH:
"A single driver fix. It resolves the build warning issue on 32bit
systems in the habannalabs driver that came in during the 5.18-rc1
merge cycle.
It has been in linux-next for all this week with no reported problems"
* tag 'char-misc-5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
habanalabs: Fix test build failures
Pull powerpc fixes from Michael Ellerman:
- Fix KVM "lost kick" race, where an attempt to pull a vcpu out of the
guest could be lost (or delayed until the next guest exit).
- Disable SCV (system call vectored) when PR KVM guests could be run.
- Fix KVM PR guests using SCV, by disallowing AIL != 0 for KVM PR
guests.
- Add a new KVM CAP to indicate if AIL == 3 is supported.
- Fix a regression when hotplugging a CPU to a memoryless/cpuless node.
- Make virt_addr_valid() stricter for 64-bit Book3E & 32-bit, which
fixes crashes seen due to hardened usercopy.
- Revert a change to max_mapnr which broke HIGHMEM.
Thanks to Christophe Leroy, Fabiano Rosas, Kefeng Wang, Nicholas Piggin,
and Srikar Dronamraju.
* tag 'powerpc-5.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
Revert "powerpc: Set max_mapnr correctly"
powerpc: Fix virt_addr_valid() for 64-bit Book3E & 32-bit
KVM: PPC: Move kvmhv_on_pseries() into kvm_ppc.h
powerpc/numa: Handle partially initialized numa nodes
powerpc/64: Fix build failure with allyesconfig in book3s_64_entry.S
KVM: PPC: Use KVM_CAP_PPC_AIL_MODE_3
KVM: PPC: Book3S PR: Disallow AIL != 0
KVM: PPC: Book3S PR: Disable SCV when AIL could be disabled
KVM: PPC: Book3S HV P9: Fix "lost kick" race
