diff options
| author | K.Prasad <Prasad.Krishnan@gmail.com> | 2012-08-02 13:46:35 +0530 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-09-04 17:29:53 +0200 |
| commit | 500ad2d8b01390c98bc6dce068bccfa9534b8212 (patch) | |
| tree | a7e1330e5380d4cb4be02820a86fbea1dc0da5c9 /kernel | |
| parent | 3ec18cd8b8f8395d0df604c62ab3bc2cf3a966b4 (diff) | |
| download | linux-500ad2d8b01390c98bc6dce068bccfa9534b8212.tar.gz | |
perf/hwpb: Invoke __perf_event_disable() if interrupts are already disabled
While debugging a warning message on PowerPC while using hardware breakpoints, it was discovered that when perf_event_disable is invoked through hw_breakpoint_handler function with interrupts disabled, a subsequent IPI in the code path would trigger a WARN_ON_ONCE message in smp_call_function_single function. This patch calls __perf_event_disable() when interrupts are already disabled, instead of perf_event_disable(). Reported-by: Edjunior Barbosa Machado <emachado@linux.vnet.ibm.com> Signed-off-by: K.Prasad <Prasad.Krishnan@gmail.com> [naveen.n.rao@linux.vnet.ibm.com: v3: Check to make sure we target current task] Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120802081635.5811.17737.stgit@localhost.localdomain [ Fixed build error on MIPS. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/core.c | 2 | ||||
| -rw-r--r-- | kernel/events/hw_breakpoint.c | 11 |
2 files changed, 11 insertions, 2 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index efef4282b8e8..7fee567153f0 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1253,7 +1253,7 @@ retry: /* * Cross CPU call to disable a performance event */ -static int __perf_event_disable(void *info) +int __perf_event_disable(void *info) { struct perf_event *event = info; struct perf_event_context *ctx = event->ctx; diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c index bb38c4d3ee12..9a7b487c6fe2 100644 --- a/kernel/events/hw_breakpoint.c +++ b/kernel/events/hw_breakpoint.c @@ -453,7 +453,16 @@ int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *att int old_type = bp->attr.bp_type; int err = 0; - perf_event_disable(bp); + /* + * modify_user_hw_breakpoint can be invoked with IRQs disabled and hence it + * will not be possible to raise IPIs that invoke __perf_event_disable. + * So call the function directly after making sure we are targeting the + * current task. + */ + if (irqs_disabled() && bp->ctx && bp->ctx->task == current) + __perf_event_disable(bp); + else + perf_event_disable(bp); bp->attr.bp_addr = attr->bp_addr; bp->attr.bp_type = attr->bp_type; |