From aa340845ae6f019e0a12321a1741c14679bb0664 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Wed, 8 Jul 2020 21:47:11 +0300 Subject: [PATCH] io_uring: fix a use after free in io_async_task_func() The "apoll" variable is freed and then used on the next line. We need to move the free down a few lines. Fixes: 0be0b0e33b0b ("io_uring: simplify io_async_task_func()") Signed-off-by: Dan Carpenter Signed-off-by: Jens Axboe --- 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 4c9a494c9f9f..14168fbc7d79 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4655,12 +4655,13 @@ static void io_async_task_func(struct callback_head *cb) /* restore ->work in case we need to retry again */ if (req->flags & REQ_F_WORK_INITIALIZED) memcpy(&req->work, &apoll->work, sizeof(req->work)); - kfree(apoll); if (!READ_ONCE(apoll->poll.canceled)) __io_req_task_submit(req); else __io_req_task_cancel(req, -ECANCELED); + + kfree(apoll); } static int io_async_wake(struct wait_queue_entry *wait, unsigned mode, int sync, -- 2.11.0