From: Minghao Chi <chi.minghao@xxxxxxxxxx> Subject: ipc/sem: do not sleep with a spin lock held We can't call kvfree() with a spin lock held, so defer it. Link: https://lkml.kernel.org/r/20211223031207.556189-1-chi.minghao@xxxxxxxxxx Fixes: fc37a3b8b438 ("[PATCH] ipc sem: use kvmalloc for sem_undo allocation") Reported-by: Zeal Robot <zealci@xxxxxxxxxx> Signed-off-by: Minghao Chi <chi.minghao@xxxxxxxxxx> Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx> Reviewed-by: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Yang Guang <cgel.zte@xxxxxxxxx> Cc: Davidlohr Bueso <dbueso@xxxxxxx> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Cc: Bhaskar Chowdhury <unixbhaskar@xxxxxxxxx> Cc: Vasily Averin <vvs@xxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- ipc/sem.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/ipc/sem.c~ipc-sem-do-not-sleep-with-a-spin-lock-held +++ a/ipc/sem.c @@ -1964,6 +1964,7 @@ static struct sem_undo *find_alloc_undo( */ 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( 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; _
