From: Jens Axboe
Snipped from commit 9ca9fb24d5febccea354089c41f96a8ad0d853f8 upstream.
While reworking the poll hashing in the v6.0 kernel, we ended up
grabbing the ctx->uring_lock in poll update/removal. This also fixed
a bug with linked timeouts racing with timeout expiry and poll
removal.
Bring back just the locking fix for that.
Reported-and-tested-by: Querijn Voet
Signed-off-by: Jens Axboe
Signed-off-by: Greg Kroah-Hartman
---
io_uring/io_uring.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index db1243dae5ca..841f013333db 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -5822,6 +5822,8 @@ static int io_poll_update(struct io_kiocb *req, unsigned int issue_flags)
struct io_kiocb *preq;
int ret2, ret = 0;
+ io_ring_submit_lock(ctx, !(issue_flags & IO_URING_F_NONBLOCK));
+
spin_lock(&ctx->completion_lock);
preq = io_poll_find(ctx, req->poll_update.old_user_data, true);
if (!preq || !io_poll_disarm(preq)) {
@@ -5853,6 +5855,7 @@ static int io_poll_update(struct io_kiocb *req, unsigned int issue_flags)
req_set_fail(req);
/* complete update request, we're done with it */
io_req_complete(req, ret);
+ io_ring_submit_unlock(ctx, !(issue_flags & IO_URING_F_NONBLOCK));
return 0;
}
--
2.25.1
