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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2009-05-13 21:26:19 +0200
committerIngo Molnar <mingo@elte.hu>2009-05-15 09:46:59 +0200
commit53020fe81eecd0b7be295868ce5850ef8f41074e (patch)
tree9dd7a48273419161c3bb74a0c9d492c626124835
parenta026dfecc035f213c1cfa0bf6407ce3155f6a9df (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.c6
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) \