After we acquire the sma->sem_perm lock in exit_sem(), we are protected against a racing IPC_RMID operation. Also at that point, we are the last user of sem_undo_list. Therefore it isn't required that we acquire or use ulp->lock.
Signed-off-by: Herton R. Krzesinski <[email protected]> --- ipc/sem.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/ipc/sem.c b/ipc/sem.c index 3b8b66b..c4c2911 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -2121,9 +2121,11 @@ void exit_sem(struct task_struct *tsk) ipc_assert_locked_object(&sma->sem_perm); list_del(&un->list_id); - spin_lock(&ulp->lock); + /* we are the last process using this ulp, acquiring ulp->lock + * isn't required. Besides that, we are also protected against + * IPC_RMID as we hold sma->sem_perm lock now + */ list_del_rcu(&un->list_proc); - spin_unlock(&ulp->lock); /* perform adjustments registered in un */ for (i = 0; i < sma->sem_nsems; i++) { -- 2.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
