[lkml]   [2019]   [Dec]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH 5.3 047/105] io_uring: ensure req->submit is copied when req is deferred
From: Jens Axboe <>

There's an issue with deferred requests through drain, where if we do
need to defer, we're not copying over the sqe_submit state correctly.
This can result in using uninitialized data when we then later go and
submit the deferred request, like this check in __io_submit_sqe():

if (unlikely(s->index >= ctx->sq_entries))
return -EINVAL;

with 's' being uninitialized, we can randomly fail this check. Fix this
by copying sqe_submit state when we defer a request.

Because it was fixed as part of a cleanup series in mainline, before
anyone realized we had this issue. That removed the separate states
of ->index vs ->submit.sqe. That series is not something I was
comfortable putting into stable, hence the much simpler addition.
Here's the patch in the series that fixes the same issue:

commit cf6fd4bd559ee61a4454b161863c8de6f30f8dca
Author: Pavel Begunkov <>
Date: Mon Nov 25 23:14:39 2019 +0300

io_uring: inline struct sqe_submit

Reported-by: Andres Freund <>
Reported-by: Tomáš Chaloupka
Signed-off-by: Jens Axboe <>
Signed-off-by: Greg Kroah-Hartman <>

fs/io_uring.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1787,7 +1787,7 @@ static int io_poll_add(struct io_kiocb *

static int io_req_defer(struct io_ring_ctx *ctx, struct io_kiocb *req,
- const struct io_uring_sqe *sqe)
+ struct sqe_submit *s)
struct io_uring_sqe *sqe_copy;

@@ -1805,7 +1805,8 @@ static int io_req_defer(struct io_ring_c
return 0;

- memcpy(sqe_copy, sqe, sizeof(*sqe_copy));
+ memcpy(&req->submit, s, sizeof(*s));
+ memcpy(sqe_copy, s->sqe, sizeof(*sqe_copy));
req->submit.sqe = sqe_copy;

INIT_WORK(&req->work, io_sq_wq_submit_work);
@@ -2114,7 +2115,7 @@ static int io_queue_sqe(struct io_ring_c
int ret;

- ret = io_req_defer(ctx, req, s->sqe);
+ ret = io_req_defer(ctx, req, s);
if (ret) {
if (ret != -EIOCBQUEUED) {

 \ /
  Last update: 2019-12-11 16:57    [W:0.322 / U:4.416 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site