* [PATCH for-next] io_uring: fix io_free_batch_list races
@ 2021-10-12 14:02 Pavel Begunkov
2021-10-12 14:59 ` Jens Axboe
0 siblings, 1 reply; 2+ messages in thread
From: Pavel Begunkov @ 2021-10-12 14:02 UTC (permalink / raw)
To: io-uring; +Cc: Jens Axboe, asml.silence
[ 158.514382] WARNING: CPU: 5 PID: 15251 at fs/io_uring.c:1141 io_free_batch_list+0x269/0x360
[ 158.514426] RIP: 0010:io_free_batch_list+0x269/0x360
[ 158.514437] Call Trace:
[ 158.514440] __io_submit_flush_completions+0xde/0x180
[ 158.514444] tctx_task_work+0x14a/0x220
[ 158.514447] task_work_run+0x64/0xa0
[ 158.514448] __do_sys_io_uring_enter+0x7c/0x970
[ 158.514450] __x64_sys_io_uring_enter+0x22/0x30
[ 158.514451] do_syscall_64+0x43/0x90
[ 158.514453] entry_SYSCALL_64_after_hwframe+0x44/0xae
We should not touch request internals including req->comp_list.next
after putting our ref if it's not final, e.g. we can start freeing
requests from the free cache.
Fixed: 62ca9cb93e7f8 ("io_uring: optimise io_free_batch_list()")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
fs/io_uring.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 73135c5c6168..55435464cee0 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2266,9 +2266,10 @@ static void io_free_batch_list(struct io_ring_ctx *ctx,
struct io_kiocb *req = container_of(node, struct io_kiocb,
comp_list);
- if (!req_ref_put_and_test(req)) {
+ if (unlikely(req->flags & REQ_F_REFCOUNT)) {
node = req->comp_list.next;
- continue;
+ if (!req_ref_put_and_test(req))
+ continue;
}
io_queue_next(req);
--
2.33.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH for-next] io_uring: fix io_free_batch_list races
2021-10-12 14:02 [PATCH for-next] io_uring: fix io_free_batch_list races Pavel Begunkov
@ 2021-10-12 14:59 ` Jens Axboe
0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2021-10-12 14:59 UTC (permalink / raw)
To: Pavel Begunkov, io-uring
On 10/12/21 8:02 AM, Pavel Begunkov wrote:
> [ 158.514382] WARNING: CPU: 5 PID: 15251 at fs/io_uring.c:1141 io_free_batch_list+0x269/0x360
> [ 158.514426] RIP: 0010:io_free_batch_list+0x269/0x360
> [ 158.514437] Call Trace:
> [ 158.514440] __io_submit_flush_completions+0xde/0x180
> [ 158.514444] tctx_task_work+0x14a/0x220
> [ 158.514447] task_work_run+0x64/0xa0
> [ 158.514448] __do_sys_io_uring_enter+0x7c/0x970
> [ 158.514450] __x64_sys_io_uring_enter+0x22/0x30
> [ 158.514451] do_syscall_64+0x43/0x90
> [ 158.514453] entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> We should not touch request internals including req->comp_list.next
> after putting our ref if it's not final, e.g. we can start freeing
> requests from the free cache.
Applied, thanks.
--
Jens Axboe
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-10-12 14:59 ` Jens Axboe
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