Commit 9bb5d40c authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar

perf: Fix mmap() accounting hole

Vince's fuzzer once again found holes. This time it spotted a leak in
the locked page accounting.

When an event had redirected output and its close() was the last
reference to the buffer we didn't have a vm context to undo accounting.

Change the code to destroy the buffer on the last munmap() and detach
all redirected events at that time. This provides us the right context
to undo the vm accounting.
Reported-and-tested-by: default avatarVince Weaver <vincent.weaver@maine.edu>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130604084421.GI8923@twins.programming.kicks-ass.net
Cc: <stable@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 26cb63ad
This diff is collapsed.
...@@ -31,7 +31,8 @@ struct ring_buffer { ...@@ -31,7 +31,8 @@ struct ring_buffer {
spinlock_t event_lock; spinlock_t event_lock;
struct list_head event_list; struct list_head event_list;
int mmap_locked; atomic_t mmap_count;
unsigned long mmap_locked;
struct user_struct *mmap_user; struct user_struct *mmap_user;
struct perf_event_mmap_page *user_page; struct perf_event_mmap_page *user_page;
......
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