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| author |   Harald Freudenberger <freude@linux.ibm.com> | 2019-04-03 13:18:22 +0200 |
|---|---|---|
| committer |   Martin Schwidefsky <schwidefsky@de.ibm.com> | 2019-04-10 17:46:24 +0200 |
| commit | 16222cfb96b02a4a3e38e52012f2a6304850c3c9 (patch) | |
| tree | 749688b1dfb6adb9012e241ae4893153957e0b1e /drivers/s390/crypto | |
| parent | s390/3270: fix lockdep false positive on view->lock (diff) | |
| download | linux-dev-16222cfb96b02a4a3e38e52012f2a6304850c3c9.tar.xz linux-dev-16222cfb96b02a4a3e38e52012f2a6304850c3c9.zip | |
s390/zcrypt: fix possible deadlock situation on ap queue remove
With commit 01396a374c3d ("s390/zcrypt: revisit ap device remove
procedure") the ap queue remove is now a two stage process. However,
a del_timer_sync() call may trigger the timer function which may
try to lock the very same spinlock as is held by the function
just initiating the del_timer_sync() call. This could end up in
a deadlock situation. Very unlikely but possible as you need to
remove an ap queue at the exact sime time when a timeout of a
request occurs.
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reported-by: Pierre Morel <pmorel@linux.ibm.com>
Fixes: commit 01396a374c3d ("s390/zcrypt: revisit ap device remove procedure")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390/crypto')
| -rw-r--r-- | drivers/s390/crypto/ap_queue.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/s390/crypto/ap_queue.c b/drivers/s390/crypto/ap_queue.c index 6a340f2c3556..5ea83dc4f1d7 100644 --- a/drivers/s390/crypto/ap_queue.c +++ b/drivers/s390/crypto/ap_queue.c @@ -751,8 +751,8 @@ void ap_queue_prepare_remove(struct ap_queue *aq) __ap_flush_queue(aq); /* set REMOVE state to prevent new messages are queued in */ aq->state = AP_STATE_REMOVE; - del_timer_sync(&aq->timeout); spin_unlock_bh(&aq->lock); + del_timer_sync(&aq->timeout); } void ap_queue_remove(struct ap_queue *aq) |