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Subject[PATCH] libcfs: Fix a sleep-in-atomic bug in cfs_wi_exit
Date
The driver may sleep under a spin lock, and the function call path is:
cfs_wi_exit (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 | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/lustre/lnet/libcfs/workitem.c b/drivers/staging/lustre/lnet/libcfs/workitem.c
index dbc2a9b..cef25c8 100644
--- a/drivers/staging/lustre/lnet/libcfs/workitem.c
+++ b/drivers/staging/lustre/lnet/libcfs/workitem.c
@@ -111,20 +111,20 @@ struct cfs_wi_sched {
{
LASSERT(!in_interrupt()); /* because we use plain spinlock */
LASSERT(!sched->ws_stopping);
+ LASSERT(wi->wi_running);
+ if (wi->wi_scheduled) {
+ LASSERT(!list_empty(&wi->wi_list));
+ LASSERT(sched->ws_nscheduled > 0);
+ }
+ LASSERT(list_empty(&wi->wi_list));

spin_lock(&sched->ws_lock);

- LASSERT(wi->wi_running);
if (wi->wi_scheduled) { /* cancel pending schedules */
- LASSERT(!list_empty(&wi->wi_list));
list_del_init(&wi->wi_list);
-
- LASSERT(sched->ws_nscheduled > 0);
sched->ws_nscheduled--;
}

- LASSERT(list_empty(&wi->wi_list));
-
wi->wi_scheduled = 1; /* LBUG future schedule attempts */
spin_unlock(&sched->ws_lock);
}
--
1.7.9.5

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