From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 272632590 for ; Sun, 22 Jan 2023 15:12:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A04FBC433D2; Sun, 22 Jan 2023 15:12:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1674400372; bh=cFzX04RxTb6QRGOAKulgwA+ApTRYhAo9lxPFayh2TjM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wNsA08Zdc55qgXAR7kK0EomD3pzi5lNVo5hMAkDY4YBOygWFDDksr6qGIsVliGrGW YViCs7ZIR4MiGqdi0Qd/r3ECXWRIjA1RUZPePcTuUTw8gt9gPIMfxsfbvbghf4Jdx5 nSeWcBym5fimHEaMOierEy6vA5E4qwG+FjNkhnjY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Christiano Haesbaert , Jens Axboe , Sasha Levin Subject: [PATCH 5.10 20/98] io_uring: dont gate task_work run on TIF_NOTIFY_SIGNAL Date: Sun, 22 Jan 2023 16:03:36 +0100 Message-Id: <20230122150230.302962175@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230122150229.351631432@linuxfoundation.org> References: <20230122150229.351631432@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Jens Axboe commit 46a525e199e4037516f7e498c18f065b09df32ac upstream. This isn't a reliable mechanism to tell if we have task_work pending, we really should be looking at whether we have any items queued. This is problematic if forward progress is gated on running said task_work. One such example is reading from a pipe, where the write side has been closed right before the read is started. The fput() of the file queues TWA_RESUME task_work, and we need that task_work to be run before ->release() is called for the pipe. If ->release() isn't called, then the read will sit forever waiting on data that will never arise. Fix this by io_run_task_work() so it checks if we have task_work pending rather than rely on TIF_NOTIFY_SIGNAL for that. The latter obviously doesn't work for task_work that is queued without TWA_SIGNAL. Reported-by: Christiano Haesbaert Cc: stable@vger.kernel.org Link: https://github.com/axboe/liburing/issues/665 Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- io_uring/io-wq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/io_uring/io-wq.c b/io_uring/io-wq.c index 87bc38b47103..81485c1a9879 100644 --- a/io_uring/io-wq.c +++ b/io_uring/io-wq.c @@ -513,7 +513,7 @@ static struct io_wq_work *io_get_next_work(struct io_wqe_acct *acct, static bool io_flush_signals(void) { - if (unlikely(test_thread_flag(TIF_NOTIFY_SIGNAL))) { + if (test_thread_flag(TIF_NOTIFY_SIGNAL) || current->task_works) { __set_current_state(TASK_RUNNING); tracehook_notify_signal(); return true; -- 2.39.0