diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-05-13 21:26:19 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-05-15 09:46:59 +0200 |
| commit | 53020fe81eecd0b7be295868ce5850ef8f41074e (patch) | |
| tree | 9dd7a48273419161c3bb74a0c9d492c626124835 | |
| parent | a026dfecc035f213c1cfa0bf6407ce3155f6a9df (diff) | |
perf_counter: Fix perf_output_copy() WARN to account for overflow
The simple reservation test in perf_output_copy() failed to take
unsigned int overflow into account, fix this.
[ Impact: fix false positive warning with more than 4GB of profiling data ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/perf_counter.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index ff166c11b69..985be0b662a 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1927,7 +1927,11 @@ static void perf_output_copy(struct perf_output_handle *handle, handle->offset = offset; - WARN_ON_ONCE(handle->offset > handle->head); + /* + * Check we didn't copy past our reservation window, taking the + * possible unsigned int wrap into account. + */ + WARN_ON_ONCE(((int)(handle->head - handle->offset)) < 0); } #define perf_output_put(handle, x) \ |