[PATCH 5.12 101/242] io_uring: fix false WARN_ONCE

Greg Kroah-Hartman
2021-07-15T19:10:23Z

From: Pavel Begunkov <asml.silence@gmail.com>

[ Upstream commit e6ab8991c5d0b0deae0961dc22c0edd1dee328f5 ]

WARNING: CPU: 1 PID: 11749 at fs/io-wq.c:244 io_wqe_wake_worker fs/io-wq.c:244 [inline]
WARNING: CPU: 1 PID: 11749 at fs/io-wq.c:244 io_wqe_enqueue+0x7f6/0x910 fs/io-wq.c:751

A WARN_ON_ONCE() in io_wqe_wake_worker() can be triggered by a valid
userspace setup. Replace it with pr_warn.

Reported-by: syzbot+ea2f1484cffe5109dc10@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/f7ede342c3342c4c26668f5168e2993e38bbd99c.1623949695.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/io-wq.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 4eba531bea5a..b836737f96f3 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -243,7 +243,8 @@ static void io_wqe_wake_worker(struct io_wqe *wqe, struct io_wqe_acct *acct)
* Most likely an attempt to queue unbounded work on an io_wq that
* wasn't setup with any unbounded workers.
*/
- WARN_ON_ONCE(!acct->max_workers);
+ if (unlikely(!acct->max_workers))
+ pr_warn_once("io-wq is not configured for unbound workers");

rcu_read_lock();
ret = io_wqe_activate_free_worker(wqe);
@@ -991,6 +992,8 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)

if (WARN_ON_ONCE(!data->free_work || !data->do_work))
return ERR_PTR(-EINVAL);
+ if (WARN_ON_ONCE(!bounded))
+ return ERR_PTR(-EINVAL);

wq = kzalloc(sizeof(*wq), GFP_KERNEL);
if (!wq)
--
2.30.2