From: Pavel Begunkov <asml.silence@xxxxxxxxx>
[ Upstream commit a298232ee6b9a1d5d732aa497ff8be0d45b5bd82 ]
WARNING: CPU: 0 PID: 10242 at lib/refcount.c:28 refcount_warn_saturate+0x15b/0x1a0 lib/refcount.c:28
RIP: 0010:refcount_warn_saturate+0x15b/0x1a0 lib/refcount.c:28
Call Trace:
__refcount_sub_and_test include/linux/refcount.h:283 [inline]
__refcount_dec_and_test include/linux/refcount.h:315 [inline]
refcount_dec_and_test include/linux/refcount.h:333 [inline]
io_put_req fs/io_uring.c:2140 [inline]
io_queue_linked_timeout fs/io_uring.c:6300 [inline]
__io_queue_sqe+0xbef/0xec0 fs/io_uring.c:6354
io_submit_sqe fs/io_uring.c:6534 [inline]
io_submit_sqes+0x2bbd/0x7c50 fs/io_uring.c:6660
__do_sys_io_uring_enter fs/io_uring.c:9240 [inline]
__se_sys_io_uring_enter+0x256/0x1d60 fs/io_uring.c:9182
io_link_timeout_fn() should put only one reference of the linked timeout
request, however in case of racing with the master request's completion
first io_req_complete() puts one and then io_put_req_deferred() is
called.
Cc: stable@xxxxxxxxxxxxxxx # 5.12+
Fixes: 9ae1f8dd372e0 ("io_uring: fix inconsistent lock state")
Reported-by: syzbot+a2910119328ce8e7996f@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Link: https://lore.kernel.org/r/ff51018ff29de5ffa76f09273ef48cb24c720368.1620417627.git.asml.silence@xxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Tested-by: Sudip Mukherjee <sudip.mukherjee@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/io_uring.c | 1 -
1 file changed, 1 deletion(-)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6266,7 +6266,6 @@ static enum hrtimer_restart io_link_time
if (prev) {
io_async_find_and_cancel(ctx, req, prev->user_data, -ETIME);
io_put_req_deferred(prev, 1);
- io_put_req_deferred(req, 1);
} else {
io_cqring_add_event(req, -ETIME, 0);
io_put_req_deferred(req, 1);
