ipc/sem: do not sleep with a spin lock held

commit 520ba724061cef59763e2b6f5b26e8387c2e5822 upstream.

We can't call kvfree() with a spin lock held, so defer it.

Link: https://lkml.kernel.org/r/20211223031207.556189-1-chi.minghao@zte.com.cn
Fixes: fc37a3b8b438 ("[PATCH] ipc sem: use kvmalloc for sem_undo allocation")
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Yang Guang <cgel.zte@gmail.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Cc: Vasily Averin <vvs@virtuozzo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/ipc/sem.c b/ipc/sem.c
index 6693daf..0dbdb98 100644 (file)
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -1964,6 +1964,7 @@ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid)
         */
        un = lookup_undo(ulp, semid);
        if (un) {
+               spin_unlock(&ulp->lock);
                kvfree(new);
                goto success;
        }
@@ -1976,9 +1977,8 @@ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid)
        ipc_assert_locked_object(&sma->sem_perm);
        list_add(&new->list_id, &sma->list_id);
        un = new;
-
-success:
        spin_unlock(&ulp->lock);
+success:
        sem_unlock(sma, -1);
 out:
        return un;