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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-12-30 16:00:35 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-12-31 13:11:31 +0100 |
| commit | 05cbaa2853cdfc255fdd04e65a82bfe9208c4e52 (patch) | |
| tree | 83a6b8ea45fe181e623aa6c532cb9176400199de | |
| parent | 48b5ba9cc98d676712da29d9931f1c88e5185ff2 (diff) | |
| download | op-kernel-dev-05cbaa2853cdfc255fdd04e65a82bfe9208c4e52.zip op-kernel-dev-05cbaa2853cdfc255fdd04e65a82bfe9208c4e52.tar.gz | |
perf: Fix NULL deref in inheritance code
Liming found a NULL deref when a task has a perf context but no
counters when it forks.
This can occur in two cases, a race during construction where
the fork hits after installing the context but before the first
counter gets inserted, or more reproducably, a fork after the
last counter is closed (which leaves the context around).
Reported-by: Wang Liming <liming.wang@windriver.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
CC: <stable@kernel.org>
LKML-Reference: <1262185684.7135.222.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/perf_event.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 03cc061..58ed1da 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -5148,7 +5148,7 @@ int perf_event_init_task(struct task_struct *child) GFP_KERNEL); if (!child_ctx) { ret = -ENOMEM; - goto exit; + break; } __perf_event_init_context(child_ctx, child); @@ -5164,7 +5164,7 @@ int perf_event_init_task(struct task_struct *child) } } - if (inherited_all) { + if (child_ctx && inherited_all) { /* * Mark the child context as a clone of the parent * context, or of whatever the parent is a clone of. @@ -5184,7 +5184,6 @@ int perf_event_init_task(struct task_struct *child) get_ctx(child_ctx->parent_ctx); } -exit: mutex_unlock(&parent_ctx->mutex); perf_unpin_context(parent_ctx); |
