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 5020B390205; Mon, 18 May 2026 19:30:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779132620; cv=none; b=nF6oUovWBW4DdLrCkZMRzqVnXDpWl6pXHlSudlKzLKCfOWM8JTFGnoRPBU+sVz0FOdIDEpfp2xNfrzHxczEUYXRwA3GxjTcdpgctfavmCk1ViI4aAWqqmXRFbulBqdemPlt4XemRT+WMOl37GRU4P/i1m0v0sY7Kk8s8NSOcBlA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779132620; c=relaxed/simple; bh=DdX2iIFCSalYqzjtTrWney+Z5bj6ec5weDXdJolRS5g=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZJD1RkdQSYbRya34fl6iGvmqBjNAWVySRBqJSAIXV0SVHRzu9GrEvEga6cjVLl5zyYlzDaYxRRv6q87t+phv8/rK64aMHEmmP+LPZ5+OEjxGw2t0FJsKQKMe1aizraZq4rg3VXFVrGCN6oaJZz637aavAoycANZabeEcc1GjOlE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=g43ZjO+c; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="g43ZjO+c" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 97102C2BCC9; Mon, 18 May 2026 19:30:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1779132620; bh=DdX2iIFCSalYqzjtTrWney+Z5bj6ec5weDXdJolRS5g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=g43ZjO+cFxhBTiOyzS+xdgNNPxwvST7r5fxpxqCH941vKep9c6n6es1+r3/ih/EwK 5ZKd2pZLQQnMNPblSna228xD5Yg0xxRmwHC0ymOMW+2P1ALQeN1uWOC5UVCewRSbBo /xpaPpT+nfQsKCSJa3ndrRo4Kr70KfbGQUvMmyUmbQJg6yjCkCxlgtbolXY6Wa2qxo Fik5lnlf36mEvpp0UyfQ57grA+1yOnNVuBK1VtL/ClPOU5aOpxpMqzo4Y96MdCM65D i+d/49aTt/HG1s+M+DA/fhj3zfxLghm2MZhKy0NqfZJBxyLbCaTF6lZR/1KS0w4JI2 XaxpqZphPl1/g== Received: from phl-compute-12.internal (phl-compute-12.internal [10.202.2.52]) by mailfauth.phl.internal (Postfix) with ESMTP id E31BBF40086; Mon, 18 May 2026 15:30:18 -0400 (EDT) Received: from phl-frontend-03 ([10.202.2.162]) by phl-compute-12.internal (MEProxy); Mon, 18 May 2026 15:30:18 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefhedrtddtgddufeeljeduucetufdoteggodetrf dotffvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfurfetoffkrfgpnffqhgenuceu rghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujf gurhepfffhvfevuffkfhggtggujgesthdtredttddtvdenucfhrhhomhepuehoqhhunhcu hfgvnhhguceosghoqhhunheskhgvrhhnvghlrdhorhhgqeenucggtffrrghtthgvrhhnpe elueehtefhtddtgfejvdejueehhfekteevueeuueekgeetieeggeehvdffhefhhfenucff ohhmrghinhepkhgvrhhnvghlrdhorhhgnecuvehluhhsthgvrhfuihiivgeptdenucfrrg hrrghmpehmrghilhhfrhhomhepsghoqhhunhdomhgvshhmthhprghuthhhphgvrhhsohhn rghlihhthidqudeijedtleekgeejuddqudejjeekheehhedvqdgsohhquhhnpeepkhgvrh hnvghlrdhorhhgsehfihigmhgvrdhnrghmvgdpnhgspghrtghpthhtohepudehpdhmohgu vgepshhmthhpohhuthdprhgtphhtthhopehurhgviihkihesghhmrghilhdrtghomhdprh gtphhtthhopehrvghgrhgvshhsihhonhhssehlvggvmhhhuhhishdrihhnfhhopdhrtghp thhtohepphgruhhlmhgtkheskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepsghoqhhunh drfhgvnhhgsehgmhgrihhlrdgtohhmpdhrtghpthhtohepjhhovghlrghgnhgvlhhfsehn vhhiughirgdrtghomhdprhgtphhtthhopehrtghusehvghgvrhdrkhgvrhhnvghlrdhorh hgpdhrtghpthhtoheplhhinhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvghlrdho rhhgpdhrtghpthhtohepghhorheslhhinhhugidrihgsmhdrtghomhdprhgtphhtthhope hfrhgvuggvrhhitgeskhgvrhhnvghlrdhorhhg X-ME-Proxy: Feedback-ID: i8dbe485b:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Mon, 18 May 2026 15:30:17 -0400 (EDT) Date: Mon, 18 May 2026 12:30:08 -0700 From: Boqun Feng To: Uladzislau Rezki Cc: Thorsten Leemhuis , paulmck@kernel.org, Boqun Feng , Joel Fernandes , RCU , LKML , Vasily Gorbik , Frederic Weisbecker , Samir , Shrikanth Hegde , Tejun Heo , Linux kernel regressions list , Jiri Slaby Subject: Re: [PATCH -next v1 05/12] srcu: Don't queue workqueue handlers to never-online CPUs Message-ID: References: <20260511175448.153326-1-urezki@gmail.com> <20260511175448.153326-6-urezki@gmail.com> <3dd5cce0-51f9-4cf1-81b8-246e6c6a633a@paulmck-laptop> <53d546e4-8db0-4e14-a79d-270212081be7@leemhuis.info> Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, May 18, 2026 at 07:05:36PM +0200, Uladzislau Rezki wrote: > On Mon, May 18, 2026 at 09:13:46AM -0700, Boqun Feng wrote: > > On Sun, May 17, 2026 at 09:11:10PM +0200, Thorsten Leemhuis wrote: > > > On 5/17/26 20:03, Paul E. McKenney wrote: > > > > On Sun, May 17, 2026 at 02:47:55PM +0200, Uladzislau Rezki wrote: > > > >> On Wed, May 13, 2026 at 12:38:01PM +0200, Thorsten Leemhuis wrote: > > > >>> On 5/11/26 19:54, Uladzislau Rezki (Sony) wrote: > > > >>>> From: "Paul E. McKenney" > > > >>>> > > > >>>> While an srcu_struct structure is in the midst of switching from CPU-0 > > > >>>> to all-CPUs state, it can attempt to invoke callbacks for CPUs that > > > >>>> have never been online. Worse yet, it can attempt in invoke callbacks > > > >>>> for CPUs that never will be online, even including imaginary CPUs not in > > > >>>> cpu_possible_mask. This can cause hangs on s390, > > > >>> > > > >>> Uladzislau, Paul, according to the fixes tag below this change fixes a > > > >>> change that went into 7.0-rc6 -- and apparently causes a "hang" on some > > > >>> architectures. So shouldn't this be heading to mainline instead of > > > >>> -next? Ideally with a stable tag to ensure backporting to 7.0.y, but > > > >>> that is a separate decision? > > > >>> > > > > FWIW, I'm happy to create an urgent PR to Linus with this fix. Since it > > fixes a commit in the previous urgent fix PR from me. Ulad, let me know > > if you want me to do it. > > > I do not mind :) So i can drop this patch! > Alright, I created the fix branch at: https://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux.git/log/?h=fixes.v7.1 And I'm going to throw some tests on it. Will send the pull request tomorrow. Regards, Boqun > -- > Uladzislau Rezki