tree 749688b1dfb6adb9012e241ae4893153957e0b1e
parent 5712f3301a12c0c3de9cc423484496b0464f2faf
author Harald Freudenberger <freude@linux.ibm.com> 1554290302 +0200
committer Martin Schwidefsky <schwidefsky@de.ibm.com> 1554911184 +0200

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>