[PATCH] libcfs: Fix a sleep-in-atomic bug in cfs_percpt_lock and cfs_percpt_unlock

[Jia-Ju Bai]

The driver may sleep under a spin lock, and the function call path is:
cfs_percpt_lock/cfs_percpt_unlock (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 
---
 drivers/staging/lustre/lnet/libcfs/libcfs_lock.c |9 +
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/lustre/lnet/libcfs/libcfs_lock.c 
b/drivers/staging/lustre/lnet/libcfs/libcfs_lock.c
index 1967b97c..a2ce092f 100644
--- a/drivers/staging/lustre/lnet/libcfs/libcfs_lock.c
+++ b/drivers/staging/lustre/lnet/libcfs/libcfs_lock.c
@@ -113,9 +113,10 @@ struct cfs_percpt_lock *
 
/* exclusive lock request */
for (i = 0; i < ncpt; i++) {
+   if (!i)
+   LASSERT(!pcl->pcl_locked);
spin_lock(pcl->pcl_locks[i]);
if (!i) {
-   LASSERT(!pcl->pcl_locked);
/* nobody should take private lock after this
 * so I wouldn't starve for too long time
 */
@@ -141,11 +142,11 @@ struct cfs_percpt_lock *
}
 
for (i = ncpt - 1; i >= 0; i--) {
-   if (!i) {
-   LASSERT(pcl->pcl_locked);
+   if (!i)
pcl->pcl_locked = 0;
-   }
spin_unlock(pcl->pcl_locks[i]);
+   if (!i)
+   LASSERT(pcl->pcl_locked);
}
 }
 EXPORT_SYMBOL(cfs_percpt_unlock);
-- 
1.7.9.5

[PATCH] libcfs: Fix a sleep-in-atomic bug in cfs_percpt_lock and cfs_percpt_unlock

[Jia-Ju Bai]

The driver may sleep under a spin lock, and the function call path is:
cfs_percpt_lock/cfs_percpt_unlock (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 
---
 drivers/staging/lustre/lnet/libcfs/libcfs_lock.c |9 +
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/lustre/lnet/libcfs/libcfs_lock.c 
b/drivers/staging/lustre/lnet/libcfs/libcfs_lock.c
index 1967b97c..a2ce092f 100644
--- a/drivers/staging/lustre/lnet/libcfs/libcfs_lock.c
+++ b/drivers/staging/lustre/lnet/libcfs/libcfs_lock.c
@@ -113,9 +113,10 @@ struct cfs_percpt_lock *
 
/* exclusive lock request */
for (i = 0; i < ncpt; i++) {
+   if (!i)
+   LASSERT(!pcl->pcl_locked);
spin_lock(pcl->pcl_locks[i]);
if (!i) {
-   LASSERT(!pcl->pcl_locked);
/* nobody should take private lock after this
 * so I wouldn't starve for too long time
 */
@@ -141,11 +142,11 @@ struct cfs_percpt_lock *
}
 
for (i = ncpt - 1; i >= 0; i--) {
-   if (!i) {
-   LASSERT(pcl->pcl_locked);
+   if (!i)
pcl->pcl_locked = 0;
-   }
spin_unlock(pcl->pcl_locks[i]);
+   if (!i)
+   LASSERT(pcl->pcl_locked);
}
 }
 EXPORT_SYMBOL(cfs_percpt_unlock);
-- 
1.7.9.5