[PATCH 3/3] io_uring: Fix race for sqes with userspace
From: Pavel Begunkov (Silence)
Date: Fri Oct 25 2019 - 05:31:55 EST
From: Pavel Begunkov <asml.silence@xxxxxxxxx>
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@xxxxxxxxx>
---
fs/io_uring.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 949c82a40d16..32f6598ecae9 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2795,13 +2795,14 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit)
submit++;
io_submit_sqe(ctx, &s, statep, &link);
}
- io_commit_sqring(ctx);
if (link)
io_queue_link_head(ctx, link, &link->submit, shadow_req);
if (statep)
io_submit_state_end(statep);
+ io_commit_sqring(ctx);
+
return submit;
}
--
2.23.0