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author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2011-01-19 12:51:39 +0100 |
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committer | Ingo Molnar <mingo@elte.hu> | 2011-01-21 16:32:42 +0100 |
commit | 547e9fd7d328af261f184bf66effc5033c886498 (patch) | |
tree | 88c2cbe138029a017769d4465798db181b1c5461 /tools | |
parent | 8c8a9b25b5de3f1eeac721cf34f4379e56d5d694 (diff) |
perf: Annotate cpuctx->ctx.mutex to avoid a lockdep splat
Lockdep spotted:
loop_1b_instruc/1899 is trying to acquire lock:
(event_mutex){+.+.+.}, at: [<ffffffff810e1908>] perf_trace_init+0x3b/0x2f7
but task is already holding lock:
(&ctx->mutex){+.+.+.}, at: [<ffffffff810eb45b>] perf_event_init_context+0xc0/0x218
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&ctx->mutex){+.+.+.}:
-> #2 (cpu_hotplug.lock){+.+.+.}:
-> #1 (module_mutex){+.+...}:
-> #0 (event_mutex){+.+.+.}:
But because the deadlock would be cpuhotplug (cpu-event) vs fork
(task-event) it cannot, in fact, happen. We can annotate this by giving the
perf_event_context used for the cpuctx a different lock class from those
used by tasks.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'tools')
0 files changed, 0 insertions, 0 deletions