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Groups > linux.kernel > #1653944

[PATCH] libcfs: Fix a sleep-in-atomic bug in cfs_wi_schedule

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The driver may sleep under a spin lock, and the function call path is:
cfs_wi_schedule (acquire the lock by spin_lock)
  LASSERT
    lbug_with_loc
      libcfs_debug_dumplog
        schedule and kthread_run --> may sleep

To fix it, all "LASSERT" is placed out of the spin_lock and spin_unlock.

Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com>
---
 drivers/staging/lustre/lnet/libcfs/workitem.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/lustre/lnet/libcfs/workitem.c b/drivers/staging/lustre/lnet/libcfs/workitem.c
index dbc2a9b..30d28cd 100644
--- a/drivers/staging/lustre/lnet/libcfs/workitem.c
+++ b/drivers/staging/lustre/lnet/libcfs/workitem.c
@@ -179,12 +179,12 @@ struct cfs_wi_sched {
 {
 	LASSERT(!in_interrupt()); /* because we use plain spinlock */
 	LASSERT(!sched->ws_stopping);
+	if (!wi->wi_scheduled)
+		LASSERT(list_empty(&wi->wi_list));
 
 	spin_lock(&sched->ws_lock);
 
 	if (!wi->wi_scheduled) {
-		LASSERT(list_empty(&wi->wi_list));
-
 		wi->wi_scheduled = 1;
 		sched->ws_nscheduled++;
 		if (!wi->wi_running) {
@@ -195,8 +195,8 @@ struct cfs_wi_sched {
 		}
 	}
 
-	LASSERT(!list_empty(&wi->wi_list));
 	spin_unlock(&sched->ws_lock);
+	LASSERT(!list_empty(&wi->wi_list));
 }
 EXPORT_SYMBOL(cfs_wi_schedule);
 
-- 
1.7.9.5

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[PATCH] libcfs: Fix a sleep-in-atomic bug in cfs_wi_schedule Jia-Ju Bai <baijiaju1990@163.com> - 2017-05-31 10:00 +0200

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