| From: Minghao Chi <chi.minghao@zte.com.cn> |
| 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@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> |
| --- |
| |
| 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; |
| _ |
