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authorPeter Zijlstra <peterz@infradead.org>2017-03-16 13:47:49 +0100
committerIngo Molnar <mingo@kernel.org>2017-03-16 14:16:52 +0100
commite7cc4865f0f31698ef2f7aac01a50e78968985b7 (patch)
tree5b4aa9c70956b5bc7b6e62edb00f2b14d007e62d /kernel/events
parente552a8389aa409e257b7dcba74f67f128f979ccc (diff)
downloadlinux-e7cc4865f0f31698ef2f7aac01a50e78968985b7.tar.bz2
perf/core: Fix event inheritance on fork()
While hunting for clues to a use-after-free, Oleg spotted that perf_event_init_context() can loose an error value with the result that fork() can succeed even though we did not fully inherit the perf event context. Spotted-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: oleg@redhat.com Cc: stable@vger.kernel.org Fixes: 889ff0150661 ("perf/core: Split context's event group list into pinned and non-pinned lists") Link: http://lkml.kernel.org/r/20170316125823.190342547@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 4742909c56e6..fc7c9a85944d 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10679,7 +10679,7 @@ static int perf_event_init_context(struct task_struct *child, int ctxn)
ret = inherit_task_group(event, parent, parent_ctx,
child, ctxn, &inherited_all);
if (ret)
- break;
+ goto out_unlock;
}
/*
@@ -10695,7 +10695,7 @@ static int perf_event_init_context(struct task_struct *child, int ctxn)
ret = inherit_task_group(event, parent, parent_ctx,
child, ctxn, &inherited_all);
if (ret)
- break;
+ goto out_unlock;
}
raw_spin_lock_irqsave(&parent_ctx->lock, flags);
@@ -10723,6 +10723,7 @@ static int perf_event_init_context(struct task_struct *child, int ctxn)
}
raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
+out_unlock:
mutex_unlock(&parent_ctx->mutex);
perf_unpin_context(parent_ctx);