From a6fa941d94b411bbd2b6421ffbde6db3c93e65ab Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 20 Aug 2012 14:59:25 +0100 Subject: perf_event: Switch to internal refcount, fix race with close() Don't mess with file refcounts (or keep a reference to file, for that matter) in perf_event. Use explicit refcount of its own instead. Deal with the race between the final reference to event going away and new children getting created for it by use of atomic_long_inc_not_zero() in inherit_event(); just have the latter free what it had allocated and return NULL, that works out just fine (children of siblings of something doomed are created as singletons, same as if the child of leader had been created and immediately killed). Signed-off-by: Al Viro Cc: stable@kernel.org Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20120820135925.GG23464@ZenIV.linux.org.uk Signed-off-by: Ingo Molnar --- include/linux/perf_event.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 7602ccb3f40e..ad04dfcd6f35 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -926,7 +926,7 @@ struct perf_event { struct hw_perf_event hw; struct perf_event_context *ctx; - struct file *filp; + atomic_long_t refcount; /* * These accumulate total time (in nanoseconds) that children -- cgit v1.2.3 From 500ad2d8b01390c98bc6dce068bccfa9534b8212 Mon Sep 17 00:00:00 2001 From: "K.Prasad" Date: Thu, 2 Aug 2012 13:46:35 +0530 Subject: 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 Signed-off-by: K.Prasad [naveen.n.rao@linux.vnet.ibm.com: v3: Check to make sure we target current task] Signed-off-by: Naveen N. Rao Acked-by: Frederic Weisbecker Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20120802081635.5811.17737.stgit@localhost.localdomain [ Fixed build error on MIPS. ] Signed-off-by: Ingo Molnar --- include/linux/perf_event.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index ad04dfcd6f35..33ed9d605f91 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1296,6 +1296,7 @@ extern int perf_swevent_get_recursion_context(void); extern void perf_swevent_put_recursion_context(int rctx); extern void perf_event_enable(struct perf_event *event); extern void perf_event_disable(struct perf_event *event); +extern int __perf_event_disable(void *info); extern void perf_event_task_tick(void); #else static inline void @@ -1334,6 +1335,7 @@ static inline int perf_swevent_get_recursion_context(void) { return -1; } static inline void perf_swevent_put_recursion_context(int rctx) { } static inline void perf_event_enable(struct perf_event *event) { } static inline void perf_event_disable(struct perf_event *event) { } +static inline int __perf_event_disable(void *info) { return -1; } static inline void perf_event_task_tick(void) { } #endif -- cgit v1.2.3