From bd2703b42decebdcddf76e277ba76b4c4a142d73 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Fri, 10 Jan 2025 20:36:45 +0000 Subject: io_uring: don't touch sqd->thread off tw add With IORING_SETUP_SQPOLL all requests are created by the SQPOLL task, which means that req->task should always match sqd->thread. Since accesses to sqd->thread should be separately protected, use req->task in io_req_normal_work_add() instead. Note, in the eyes of io_req_normal_work_add(), the SQPOLL task struct is always pinned and alive, and sqd->thread can either be the task or NULL. It's only problematic if the compiler decides to reload the value after the null check, which is not so likely. Cc: stable@vger.kernel.org Cc: Bui Quang Minh Reported-by: lizetao Fixes: 78f9b61bd8e54 ("io_uring: wake SQPOLL task when task_work is added to an empty queue") Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/1cbbe72cf32c45a8fee96026463024cd8564a7d7.1736541357.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- io_uring/io_uring.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'io_uring') diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index d3403c8216db..5eb119002099 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1226,10 +1226,7 @@ static void io_req_normal_work_add(struct io_kiocb *req) /* SQPOLL doesn't need the task_work added, it'll run it itself */ if (ctx->flags & IORING_SETUP_SQPOLL) { - struct io_sq_data *sqd = ctx->sq_data; - - if (sqd->thread) - __set_notify_signal(sqd->thread); + __set_notify_signal(tctx->task); return; } -- cgit v1.2.3