diff options
author | Steven Rostedt <srostedt@redhat.com> | 2010-03-13 00:48:41 (GMT) |
---|---|---|
committer | Steven Rostedt <rostedt@goodmis.org> | 2010-03-13 01:29:20 (GMT) |
commit | 283740c619d211e34572cc93c8cdba92ccbdb9cc (patch) | |
tree | 3bdce475017ff9a5fe82c6d214d27b27e555320c /kernel/trace/trace.c | |
parent | ea14eb714041d40fcc5180b5a586034503650149 (diff) | |
download | linux-fsl-qoriq-283740c619d211e34572cc93c8cdba92ccbdb9cc.tar.xz |
tracing: Use same local variable when resetting the ring buffer
In the ftrace code that resets the ring buffer it references the
buffer with a local variable, but then uses the tr->buffer as the
parameter to reset. If the wakeup tracer is running, which can
switch the tr->buffer with the max saved buffer, this can break
the requirement of disabling the buffer before the reset.
buffer = tr->buffer;
ring_buffer_record_disable(buffer);
synchronize_sched();
__tracing_reset(tr->buffer, cpu);
If the tr->buffer is swapped, then the reset is not happening to the
buffer that was disabled. This will cause the ring buffer to fail.
Found with Li Zefan's ftrace_stress_test.
Cc: stable@kernel.org
Reported-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace.c')
-rw-r--r-- | kernel/trace/trace.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 6af8d7b..60de37b 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -840,10 +840,10 @@ out: mutex_unlock(&trace_types_lock); } -static void __tracing_reset(struct trace_array *tr, int cpu) +static void __tracing_reset(struct ring_buffer *buffer, int cpu) { ftrace_disable_cpu(); - ring_buffer_reset_cpu(tr->buffer, cpu); + ring_buffer_reset_cpu(buffer, cpu); ftrace_enable_cpu(); } @@ -855,7 +855,7 @@ void tracing_reset(struct trace_array *tr, int cpu) /* Make sure all commits have finished */ synchronize_sched(); - __tracing_reset(tr, cpu); + __tracing_reset(buffer, cpu); ring_buffer_record_enable(buffer); } @@ -873,7 +873,7 @@ void tracing_reset_online_cpus(struct trace_array *tr) tr->time_start = ftrace_now(tr->cpu); for_each_online_cpu(cpu) - __tracing_reset(tr, cpu); + __tracing_reset(buffer, cpu); ring_buffer_record_enable(buffer); } |