Now io_complete_rw_common() puts a ref, extra io_req_put()
in io_iopoll_queue() causes undeflow. Remove it.
[ 455.998620] refcount_t: underflow; use-after-free.
[ 455.998743] WARNING: CPU: 6 PID: 285394 at lib/refcount.c:28
refcount_warn_saturate+0xae/0xf0
[ 455.998772] CPU: 6 PID: 285394 Comm: read-write2 Tainted: G
I E 5.8.0-rc2-00048-g1b1aa738f167-dirty #509
[ 455.998772] RIP: 0010:refcount_warn_saturate+0xae/0xf0
...
[ 455.998778] Call Trace:
[ 455.998778] io_put_req+0x44/0x50
[ 455.998778] io_iopoll_complete+0x245/0x370
[ 455.998779] io_iopoll_getevents+0x12f/0x1a0
[ 455.998779] io_iopoll_reap_events.part.0+0x5e/0xa0
[ 455.998780] io_ring_ctx_wait_and_kill+0x132/0x1c0
[ 455.998780] io_uring_release+0x20/0x30
[ 455.998780] __fput+0xcd/0x230
[ 455.998781] ____fput+0xe/0x10
[ 455.998781] task_work_run+0x67/0xa0
[ 455.998781] do_exit+0x35d/0xb70
[ 455.998782] do_group_exit+0x43/0xa0
[ 455.998783] get_signal+0x140/0x900
[ 455.998783] do_signal+0x37/0x780
[ 455.998784] __prepare_exit_to_usermode+0x126/0x1c0
[ 455.998785] __syscall_return_slowpath+0x3b/0x1c0
[ 455.998785] do_syscall_64+0x5f/0xa0
[ 455.998785] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: a1d7c393c47 ("io_uring: enable READ/WRITE to use deferred completions")
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
fs/io_uring.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index bf236ba10601..52441f2465fe 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1904,7 +1904,6 @@ static void io_iopoll_queue(struct list_head *again)
/* shouldn't happen unless io_uring is dying, cancel reqs */
if (unlikely(!current->mm)) {
io_complete_rw_common(&req->rw.kiocb, -EAGAIN, NULL);
- io_put_req(req);
continue;
}
--
2.24.0
