From: Pavel Begunkov <asml.silence@gmail.com>
Date: Fri, 25 Oct 2019 12:31:31 +0300
Subject: io_uring: Fix race for sqes with userspace
Git-commit: 935d1e45908afb8853c497f2c2bbbb685dec51dc
Patch-mainline: 5.4-rc5
References: bnc#1151927 5.3.8
io_ring_submit() finalises with
1. io_commit_sqring(), which releases sqes to the userspace
2. Then calls to io_queue_link_head(), accessing released head's sqe
Reorder them.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
fs/io_uring.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2468,13 +2468,14 @@ static int io_ring_submit(struct io_ring
submit++;
io_submit_sqe(ctx, &s, statep, &link);
}
- io_commit_sqring(ctx);
if (link)
io_queue_sqe(ctx, link, &link->submit);
if (statep)
io_submit_state_end(statep);
+ io_commit_sqring(ctx);
+
return submit;
}