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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-03-25 12:30:24 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-04-06 09:30:33 +0200 |
| commit | 63e35b25d6b5c3136d22ef249dbbf96716aa08bf (patch) | |
| tree | 213eaa8ffcbdd3efd0c8489a84658b9fc1b870c7 /kernel | |
| parent | 5c1481943250ab65fa5130e05ec479c93216e9f7 (diff) | |
| download | lwn-63e35b25d6b5c3136d22ef249dbbf96716aa08bf.tar.gz lwn-63e35b25d6b5c3136d22ef249dbbf96716aa08bf.zip | |
perf_counter: sanity check on the output API
Ensure we never write more than we said we would.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Orig-LKML-Reference: <20090325113316.921433024@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/perf_counter.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index d76e3112d386..7669afe82cc7 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1422,6 +1422,7 @@ struct perf_output_handle { struct perf_counter *counter; struct perf_mmap_data *data; unsigned int offset; + unsigned int head; int wakeup; }; @@ -1447,6 +1448,7 @@ static int perf_output_begin(struct perf_output_handle *handle, handle->counter = counter; handle->data = data; handle->offset = offset; + handle->head = head; handle->wakeup = (offset >> PAGE_SHIFT) != (head >> PAGE_SHIFT); return 0; @@ -1485,6 +1487,8 @@ static void perf_output_copy(struct perf_output_handle *handle, } while (len); handle->offset = offset; + + WARN_ON_ONCE(handle->offset > handle->head); } #define perf_output_put(handle, x) \ |