aboutsummaryrefslogtreecommitdiff
path: root/kernel
diff options
context:
space:
mode:
authorPeter Zijlstra <a.p.zijlstra@chello.nl>2009-12-30 16:00:35 +0100
committerIngo Molnar <mingo@elte.hu>2009-12-31 13:11:31 +0100
commit05cbaa2853cdfc255fdd04e65a82bfe9208c4e52 (patch)
tree83a6b8ea45fe181e623aa6c532cb9176400199de /kernel
parent48b5ba9cc98d676712da29d9931f1c88e5185ff2 (diff)
downloadvexpress-lsk-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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/perf_event.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 03cc061398d..58ed1dae587 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);