From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7876BC433E0 for ; Sun, 5 Jul 2020 14:08:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5321720724 for ; Sun, 5 Jul 2020 14:08:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593958112; bh=hURgd86nZ++VXTvq90RC/EanMIWQDFFVZQFfdrVmnAg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=pKQxPt+01NdY61t03TqnLFTDbKPGn/5zahhbco9B/b+zv6CJYeU/AeHpz9PglI9sN uRLsnLuT+NsmWljhgrprSf33riCsUNFL461LFWFhgrCxcctBTkpK3DbYhz3eh5DXUu OauLj9XcI+7RwTv1lMQO+rmzRwgqDSbZVzO0oKg8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726747AbgGEOIb (ORCPT ); Sun, 5 Jul 2020 10:08:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:33456 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726538AbgGEOIb (ORCPT ); Sun, 5 Jul 2020 10:08:31 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C0AE120724; Sun, 5 Jul 2020 14:08:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593958111; bh=hURgd86nZ++VXTvq90RC/EanMIWQDFFVZQFfdrVmnAg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XQ6ReEkExPIqQ7PuTsLcUq2rV9CF7qzDV5yMmobHAO5WiFtb4uBacPtqZPEh/yzFy u0JQ2RQ/RFkJC7wSMGYFJb6rs2Bwq7oj+NAf1X1hsfDP4iu5rRuGzsTSiTsO6QZHCA qvKimCrfTFaViTxDYaqRY/ZhyMbOHpPommi1kKZA= Date: Sun, 5 Jul 2020 16:08:33 +0200 From: Greg KH To: Sasha Levin Cc: axboe@kernel.dk, stable@vger.kernel.org Subject: Re: FAILED: patch "[PATCH] io_uring: use signal based task_work running" failed to apply to 5.7-stable tree Message-ID: <20200705140833.GA1299492@kroah.com> References: <15939484161622@kroah.com> <20200705134910.GJ2722994@sasha-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200705134910.GJ2722994@sasha-vm> Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Sun, Jul 05, 2020 at 09:49:10AM -0400, Sasha Levin wrote: > On Sun, Jul 05, 2020 at 01:26:56PM +0200, gregkh@linuxfoundation.org wrote: > > > > The patch below does not apply to the 5.7-stable tree. > > If someone wants it applied there, or to any other stable or longterm > > tree, then please email the backport, including the original git commit > > id to . > > > > thanks, > > > > greg k-h > > > > ------------------ original commit in Linus's tree ------------------ > > > > > From ce593a6c480a22acba08795be313c0c6d49dd35d Mon Sep 17 00:00:00 2001 > > From: Jens Axboe > > Date: Tue, 30 Jun 2020 12:39:05 -0600 > > Subject: [PATCH] io_uring: use signal based task_work running > > > > Since 5.7, we've been using task_work to trigger async running of > > requests in the context of the original task. This generally works > > great, but there's a case where if the task is currently blocked > > in the kernel waiting on a condition to become true, it won't process > > task_work. Even though the task is woken, it just checks whatever > > condition it's waiting on, and goes back to sleep if it's still false. > > > > This is a problem if that very condition only becomes true when that > > task_work is run. An example of that is the task registering an eventfd > > with io_uring, and it's now blocked waiting on an eventfd read. That > > read could depend on a completion event, and that completion event > > won't get trigged until task_work has been run. > > > > Use the TWA_SIGNAL notification for task_work, so that we ensure that > > the task always runs the work when queued. > > > > Cc: stable@vger.kernel.org # v5.7 > > Signed-off-by: Jens Axboe > > This patch depends on e91b48162332 ("task_work: teach task_work_add() to > do signal_wake_up()"), I've queued both for 5.7. Great, thanks for adding that. greg k-h