Xiao Yang 7c6feb347a tracing: Fix the race between registering 'snapshot' event trigger and triggering 'snapshot' operation ...

commit 0bbe7f719985efd9adb3454679ecef0984cb6800 upstream.

Traced event can trigger 'snapshot' operation(i.e. calls snapshot_trigger()
or snapshot_count_trigger()) when register_snapshot_trigger() has completed
registration but doesn't allocate buffer for 'snapshot' event trigger.  In
the rare case, 'snapshot' operation always detects the lack of allocated
buffer so make register_snapshot_trigger() allocate buffer first.

trigger-snapshot.tc in kselftest reproduces the issue on slow vm:
-----------------------------------------------------------
cat trace
...
ftracetest-3028  [002] ....   236.784290: sched_process_fork: comm=ftracetest pid=3028 child_comm=ftracetest child_pid=3036
     <...>-2875  [003] ....   240.460335: tracing_snapshot_instance_cond: *** SNAPSHOT NOT ALLOCATED ***
     <...>-2875  [003] ....   240.460338: tracing_snapshot_instance_cond: *** stopping trace here!   ***
-----------------------------------------------------------

Link: http://lkml.kernel.org/r/20200414015145.66236-1-yangx.jy@cn.fujitsu.com

Cc: stable@vger.kernel.org
Fixes: 93e31ffbf4 ("tracing: Add 'snapshot' event trigger command")
Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2020-04-24 07:57:21 +02:00

..

blktrace.c

tracing/blktrace: Fix to allow setting same value

2018-09-09 20:04:34 +02:00

bpf_trace.c

bpf: fix check of allowed specifiers in bpf_trace_printk

2018-12-17 21:55:10 +01:00

ftrace.c

ftrace: Avoid potential division by zero in function profiler

2020-01-12 11:22:43 +01:00

Kconfig

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2015-11-10 18:11:41 -08:00

Makefile

Makefile: Mute warning for __builtin_return_address(>0) for tracing only

2016-09-30 10:18:35 +02:00

power-traces.c

PM / sleep: export suspend_resume trace event

2015-01-30 02:10:41 +01:00

ring_buffer_benchmark.c

ring_buffer: Remove unneeded smp_wmb() before wakeup of reader benchmark

2015-11-03 16:19:02 -05:00

ring_buffer.c

trace: Fix preempt_enable_no_resched() abuse

2019-05-16 19:44:43 +02:00

rpm-traces.c

…

trace_benchmark.c

tracing: Only benchmark the time tracepoints take if tracing is on

2015-11-02 13:34:58 -05:00

trace_benchmark.h

tracing: Add tracepoint benchmark tracepoint

2014-05-29 22:49:54 -04:00

trace_branch.c

tracing: Remove {start,stop}_branch_trace

2015-10-21 10:10:09 -04:00

trace_clock.c

tracing: Export tracing clock functions

2015-05-12 15:56:57 -04:00

trace_entries.h

tracing: %pF is only for function pointers

2015-03-25 08:57:22 -04:00

trace_event_perf.c

treewide: Remove old email address

2015-11-23 09:44:58 +01:00

trace_events_filter_test.h

…

trace_events_filter.c

tracing: Fix regex_match_front() to not over compare the test string

2018-05-16 10:06:51 +02:00

trace_events_trigger.c

tracing: Fix the race between registering 'snapshot' event trigger and triggering 'snapshot' operation

2020-04-24 07:57:21 +02:00

trace_events.c

tracing: Fix partial reading of trace event's id file

2019-06-11 12:23:46 +02:00

trace_export.c

tracing: ftrace_event_is_function() can return boolean

2015-11-02 14:28:05 -05:00

trace_functions_graph.c

tracing: Fix missing return symbol in function_graph output

2018-07-11 16:03:48 +02:00

trace_functions.c

tracing/trivial: Fix typos and make an int into a bool

2014-11-20 10:05:36 -05:00

trace_irqsoff.c

tracing: Have preempt(irqs)off trace preempt disabled functions

2016-04-12 09:08:59 -07:00

trace_kdb.c

tracing: Silence GCC 9 array bounds warning

2019-07-10 09:56:31 +02:00

trace_kprobe.c

tracing: Quiet gcc warning about maybe unused link variable

2018-08-06 16:24:30 +02:00

trace_mmiotrace.c

tracing: Pass trace_array into trace_buffer_unlock_commit()

2015-09-25 17:38:44 -04:00

trace_nop.c

tracing: Remove unneeded includes of debugfs.h and fs.h

2015-01-22 11:19:48 -05:00

trace_output.c

tracing: Move trace_flags from global to a trace_array field

2015-09-30 15:22:55 -04:00

trace_output.h

tracing: Turn seq_print_user_ip() into a static function

2015-09-28 10:16:12 -04:00

trace_printk.c

tracing: Handle NULL formats in hold_module_trace_bprintk_format()

2016-07-27 09:47:32 -07:00

trace_probe.c

tracing: probeevent: Fix to support minus offset from symbol

2018-03-28 18:40:15 +02:00

trace_probe.h

tracing: probeevent: Fix to support minus offset from symbol

2018-03-28 18:40:15 +02:00

trace_sched_switch.c

sched/core: Fix trace_sched_switch()

2015-10-06 17:08:15 +02:00

trace_sched_wakeup.c

kernel/trace: Fix do not unregister tracepoints when register sched_migrate_task fail

2020-01-14 20:03:01 +01:00

trace_selftest_dynamic.c

…

trace_selftest.c

ftrace: Fix selftest goto location on error

2017-09-27 11:00:16 +02:00

trace_seq.c

tracing: use %*pb[l] to print bitmaps including cpumasks and nodemasks

2015-02-13 21:21:37 -08:00

trace_stack.c

tracing: Have stack tracer compile when MCOUNT_INSN_SIZE is not defined

2020-01-14 20:03:01 +01:00

trace_stat.c

tracing: Fix very unlikely race of registering two stat tracers

2020-02-28 15:38:55 +01:00

trace_stat.h

…

trace_syscalls.c

tracing: Move trace_flags from global to a trace_array field

2015-09-30 15:22:55 -04:00

trace_uprobe.c

tracing/uprobes: Fix output for multiple string arguments

2019-02-20 10:13:22 +01:00

trace.c

fs: prevent page refcount overflow in pipe_buf_get

2020-03-11 07:51:15 +01:00

trace.h

tracing: Silence GCC 9 array bounds warning

2019-07-10 09:56:31 +02:00