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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39964C433F5 for ; Wed, 1 Dec 2021 21:09:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343983AbhLAVNL (ORCPT ); Wed, 1 Dec 2021 16:13:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245319AbhLAVND (ORCPT ); Wed, 1 Dec 2021 16:13:03 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 635F3C061748; Wed, 1 Dec 2021 13:09:42 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id ADAC8CE20EC; Wed, 1 Dec 2021 21:09:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D5625C53FCD; Wed, 1 Dec 2021 21:09:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1638392978; bh=16Nfdd8O1UZIPT+mMKwLqE1crTPMbdMUdXr+0/0h0fU=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=O3ylG/108bQIwvBrXqecGHm8DjYoBBRtWM14LWqRYpLrmF+vvD2DyNiurWSpFb0t2 oWe0QD5EnDi0q/Gh8pWlaPEMUTvxA+yUZQ39spr9FqPA1iV2oq0WOBVA9MMWYYws3E LpUTQp1jRacpFywVHrW4aaC6uE8xo8ld2jK8zlHX2B9mE7OLR5QEBxd3siKTVFUSeZ 4OWPNRTBHEtznbuTUCy0BEQRtwtRhB7UcKo6+/rkzWCSLH2Wy9WSE1N0ImEC9BXpbQ 42NApEttKJ+P9isVpNxjPbORbXHts6bqvZhUClJG76TXb4tSXqElF/I+XWqG1QjNHs 26EQNz2B0toSg== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 90C405C1107; Wed, 1 Dec 2021 13:09:38 -0800 (PST) Date: Wed, 1 Dec 2021 13:09:38 -0800 From: "Paul E. McKenney" To: syzbot Cc: bigeasy@linutronix.de, jgross@suse.com, jiangshanlai@gmail.com, joel@joelfernandes.org, josh@joshtriplett.org, linux-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com, mingo@kernel.org, namit@vmware.com, netdev@vger.kernel.org, peterz@infradead.org, rcu@vger.kernel.org, rdunlap@infradead.org, rostedt@goodmis.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] WARNING in trc_read_check_handler Message-ID: <20211201210938.GL641268@paulmck-ThinkPad-P17-Gen-1> Reply-To: paulmck@kernel.org References: <00000000000069924b05c8cc3b84@google.com> <000000000000b7e3ee05d21bd19d@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000000000000b7e3ee05d21bd19d@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 01, 2021 at 12:50:07PM -0800, syzbot wrote: > syzbot suspects this issue was fixed by commit: > > commit 96017bf9039763a2e02dcc6adaa18592cd73a39d > Author: Paul E. McKenney > Date: Wed Jul 28 17:53:41 2021 +0000 > > rcu-tasks: Simplify trc_read_check_handler() atomic operations > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1281d89db00000 > start commit: 5319255b8df9 selftests/bpf: Skip verifier tests that fail .. > git tree: bpf-next > kernel config: https://syzkaller.appspot.com/x/.config?x=9290a409049988d4 > dashboard link: https://syzkaller.appspot.com/bug?extid=fe9d8c955bd1d0f02dc1 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14990477300000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=105ebd84b00000 > > If the result looks correct, please mark the issue as fixed by replying with: #syz fix: rcu-tasks: Simplify trc_read_check_handler() atomic operations > For information about bisection process see: https://goo.gl/tpsmEJ#bisection Give or take. There were quite a few related bugs, so some or all of the following commits might also have helped: cbe0d8d91415c rcu-tasks: Wait for trc_read_check_handler() IPIs 18f08e758f34e rcu-tasks: Add trc_inspect_reader() checks for exiting critical section 46aa886c483f5 rcu-tasks: Fix IPI failure handling in trc_wait_for_one_reader Quibbles aside, it is nice to get an automated email about having fixed a bug as opposed to having added one. ;-) Thanx, Paul