From: Fan Yong Date: Wed, 4 Nov 2015 18:40:04 +0000 (-0500) Subject: staging: lustre: race condition for check/use cfs_fail_val X-Git-Tag: v4.5-rc1~122^2~415 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=78368d578e9eab8dc9d42b9e9a2be78a98f4e9d9;p=karo-tx-linux.git staging: lustre: race condition for check/use cfs_fail_val There are some race conditions when check/use cfs_fail_val. For example: when inject failure stub for LFSCK test as following: 764 if (OBD_FAIL_CHECK(OBD_FAIL_LFSCK_DELAY2) && 765 cfs_fail_val > 0) { 766 struct l_wait_info lwi; 767 768 lwi = LWI_TIMEOUT(cfs_time_seconds(cfs_fail_val), 769 NULL, NULL); 770 l_wait_event(thread->t_ctl_waitq, 771 !thread_is_running(thread), 772 &lwi); 773 774 if (unlikely(!thread_is_running(thread))) { 775 CDEBUG(D_LFSCK, "%s: scan dir exit for engine " 776 "stop, parent "DFID", cookie "LPX64"n", 777 lfsck_lfsck2name(lfsck), 778 PFID(lfsck_dto2fid(dir)), 779 lfsck->li_cookie_dir); 780 RETURN(0); 781 } 782 } The "cfs_fail_val" may be changed as zero by others after the check at the line 765 but before using it at the line 768. Then the LFSCK engine will fall into "wait" until someone run "lfsck_stop". Signed-off-by: Fan Yong Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6146 Reviewed-on: http://review.whamcloud.com/13481 Reviewed-by: Lai Siyao Reviewed-by: Andreas Dilger Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/lustre/lustre/libcfs/fail.c b/drivers/staging/lustre/lustre/libcfs/fail.c index d39fecebd12d..ea059b012a66 100644 --- a/drivers/staging/lustre/lustre/libcfs/fail.c +++ b/drivers/staging/lustre/lustre/libcfs/fail.c @@ -126,7 +126,7 @@ int __cfs_fail_timeout_set(__u32 id, __u32 value, int ms, int set) int ret; ret = __cfs_fail_check_set(id, value, set); - if (ret) { + if (ret && likely(ms > 0)) { CERROR("cfs_fail_timeout id %x sleeping for %dms\n", id, ms); set_current_state(TASK_UNINTERRUPTIBLE);