diff options
author | Peter Zijlstra <peterz@infradead.org> | 2009-06-08 18:18:39 +0200 |
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committer | Steven Rostedt <rostedt@goodmis.org> | 2009-06-08 18:50:20 -0400 |
commit | 1f8a6a10fb9437eac3f516ea4324a19087872f30 (patch) | |
tree | 944f73519ef205c3baccd130d93ed70f7e7bc790 /mm | |
parent | 918143e8b7d6153d7a83a3f854323407939f4a7e (diff) |
ring-buffer: pass in lockdep class key for reader_lock
On Sun, 7 Jun 2009, Ingo Molnar wrote:
> Testing tracer sched_switch: <6>Starting ring buffer hammer
> PASSED
> Testing tracer sysprof: PASSED
> Testing tracer function: PASSED
> Testing tracer irqsoff:
> =============================================
> PASSED
> Testing tracer preemptoff: PASSED
> Testing tracer preemptirqsoff: [ INFO: possible recursive locking detected ]
> PASSED
> Testing tracer branch: 2.6.30-rc8-tip-01972-ge5b9078-dirty #5760
> ---------------------------------------------
> rb_consumer/431 is trying to acquire lock:
> (&cpu_buffer->reader_lock){......}, at: [<c109eef7>] ring_buffer_reset_cpu+0x37/0x70
>
> but task is already holding lock:
> (&cpu_buffer->reader_lock){......}, at: [<c10a019e>] ring_buffer_consume+0x7e/0xc0
>
> other info that might help us debug this:
> 1 lock held by rb_consumer/431:
> #0: (&cpu_buffer->reader_lock){......}, at: [<c10a019e>] ring_buffer_consume+0x7e/0xc0
The ring buffer is a generic structure, and can be used outside of
ftrace. If ftrace traces within the use of the ring buffer, it can produce
false positives with lockdep.
This patch passes in a static lock key into the allocation of the ring
buffer, so that different ring buffers will have their own lock class.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1244477919.13761.9042.camel@twins>
[ store key in ring buffer descriptor ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'mm')
0 files changed, 0 insertions, 0 deletions