diff options
| author | Pavel Begunkov <asml.silence@gmail.com> | 2025-01-10 15:31:23 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-01-10 22:00:19 +0100 |
| commit | 4b7cfa8b6c28a9fa22b86894166a1a34f6d630ba (patch) | |
| tree | 180f17f087ecc989f46e00518cf4c5861981ad6c /io_uring | |
| parent | io_uring/eventfd: ensure io_eventfd_signal() defers another RCU period (diff) | |
| download | linux-4b7cfa8b6c28a9fa22b86894166a1a34f6d630ba.tar.xz linux-4b7cfa8b6c28a9fa22b86894166a1a34f6d630ba.zip | |
io_uring/sqpoll: zero sqd->thread on tctx errors
Syzkeller reports:
BUG: KASAN: slab-use-after-free in thread_group_cputime+0x409/0x700 kernel/sched/cputime.c:341
Read of size 8 at addr ffff88803578c510 by task syz.2.3223/27552
Call Trace:
<TASK>
...
kasan_report+0x143/0x180 mm/kasan/report.c:602
thread_group_cputime+0x409/0x700 kernel/sched/cputime.c:341
thread_group_cputime_adjusted+0xa6/0x340 kernel/sched/cputime.c:639
getrusage+0x1000/0x1340 kernel/sys.c:1863
io_uring_show_fdinfo+0xdfe/0x1770 io_uring/fdinfo.c:197
seq_show+0x608/0x770 fs/proc/fd.c:68
...
That's due to sqd->task not being cleared properly in cases where
SQPOLL task tctx setup fails, which can essentially only happen with
fault injection to insert allocation errors.
Cc: stable@vger.kernel.org
Fixes: 1251d2025c3e1 ("io_uring/sqpoll: early exit thread if task_context wasn't allocated")
Reported-by: syzbot+3d92cfcfa84070b0a470@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/efc7ec7010784463b2e7466d7b5c02c2cb381635.1736519461.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/sqpoll.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c index 9e5bd79fd2b5..8961a3c1e73c 100644 --- a/io_uring/sqpoll.c +++ b/io_uring/sqpoll.c @@ -268,8 +268,12 @@ static int io_sq_thread(void *data) DEFINE_WAIT(wait); /* offload context creation failed, just exit */ - if (!current->io_uring) + if (!current->io_uring) { + mutex_lock(&sqd->lock); + sqd->thread = NULL; + mutex_unlock(&sqd->lock); goto err_out; + } snprintf(buf, sizeof(buf), "iou-sqp-%d", sqd->task_pid); set_task_comm(current, buf); |