The while loop in sock_fanout_read_ring() checks mmap region bounds after access, causing it to segfault. Fix it to check count before accessing header->tp_status. This problem can be reproduced consistently when the test in run as follows: make -C tools/testing/selftests TARGETS=net run_tests or make run_tests from tools/testing/selftests or make run_test from tools/testing/selftests/net Signed-off-by: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> --- tools/testing/selftests/net/psock_fanout.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/net/psock_fanout.c b/tools/testing/selftests/net/psock_fanout.c index 57b9c2b..6f67333 100644 --- a/tools/testing/selftests/net/psock_fanout.c +++ b/tools/testing/selftests/net/psock_fanout.c @@ -128,7 +128,7 @@ static int sock_fanout_read_ring(int fd, void *ring) struct tpacket2_hdr *header = ring; int count = 0; - while (header->tp_status & TP_STATUS_USER && count < RING_NUM_FRAMES) { + while (count < RING_NUM_FRAMES && header->tp_status & TP_STATUS_USER) { count++; header = ring + (count * getpagesize()); } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html