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io_uring: Fix race for sqes with userspace

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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>
This commit is contained in:
Pavel Begunkov 2019-10-25 12:31:31 +03:00 committed by Jens Axboe
parent fb5ccc9878
commit 935d1e4590
1 changed files with 2 additions and 1 deletions
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3
fs/io_uring.c
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@ -2795,13 +2795,14 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit)
submit++; submit++;
io_submit_sqe(ctx, &s, statep, &link); io_submit_sqe(ctx, &s, statep, &link);
} }
io_commit_sqring(ctx);
if (link) if (link)
io_queue_link_head(ctx, link, &link->submit, shadow_req); io_queue_link_head(ctx, link, &link->submit, shadow_req);
if (statep) if (statep)
io_submit_state_end(statep); io_submit_state_end(statep);
io_commit_sqring(ctx);
return submit; return submit;
} }