Commit 53020fe8 authored May 13, 2009 by Peter Zijlstra Committed by Ingo Molnar May 15, 2009

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>

parent a026dfec

kernel/perf_counter.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -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) \