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 E146CC433F5 for ; Sat, 4 Dec 2021 09:51:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1384538AbhLDJyY (ORCPT ); Sat, 4 Dec 2021 04:54:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57362 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244915AbhLDJyY (ORCPT ); Sat, 4 Dec 2021 04:54:24 -0500 Received: from mail-oi1-x22b.google.com (mail-oi1-x22b.google.com [IPv6:2607:f8b0:4864:20::22b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D8697C061751 for ; Sat, 4 Dec 2021 01:50:58 -0800 (PST) Received: by mail-oi1-x22b.google.com with SMTP id u74so10886726oie.8 for ; Sat, 04 Dec 2021 01:50:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=PWtuf7THffxb2Es2MbGam96iZCp8PZrhow4j8nKkn2I=; b=qCwONOHi/mWcgDGZzxk3CEBQ7bn33eptyIeHj0MQtbU8CfuJnOy2EoRpBvu0gZefxB D2N7xY45c5w/TIn0CEJZLZ71rP+t5v5rFFqJ9/6bU5/y5onp0ymLK9qOxd/DLgq7bV1Y bzWrUNC9Tcg3jsO5Rw6273N75GEx1yYZBtwOGG5Oo0oz4V72aTMh/eGKIR0Qp2daPmiI 3NK7P+Of2NUkXefTW/qXCXESnerCkQn9RjmymSTR9e3nYSWmVYj3aQptegJnCqw/4qMv 4Hon2M7qYOmy2Ndju9kig0yzXSN6ouSjgZN7lHChSGN6kjyUWTsjgLppNLOgEpGAw1KT pOUQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=PWtuf7THffxb2Es2MbGam96iZCp8PZrhow4j8nKkn2I=; b=7HEIzjMOeN8oBb/8hPNsWgs66G2gqbWWqrgynoDt+DXvKWIwYUtEOSnHubUhw/TLuw px08TcUyrIqCkS+BHlEtZExiFqHg4B1N0rAsTVLLXB/Op56Ja0Cey6OwIHhR2IHWrsX6 GmQoXvIS16qIjstTj50XqG30RJ6edQYEqZ/bklJuDssU+HnsGkZUb7pyWwqsz8BYqagI kB6IvN2B3JgQALhrJ302byK5kgiY+EBn6bCifeBW4asZ9CZZ/+jvCV+obgX0/DJ0Hkrp PrEy/6/3yQzPNBNXjfqhk/7eClUH8WCOTooKTAqowSxLMo8RXCdBpY91nj19tObPCmfj xP1w== X-Gm-Message-State: AOAM531WuHe8oz2OWwPZ3lmmNc7E8RAJ8gTvq4EvWDoIrgtX4WLi2xNq iUkJ5c41I72i6G/ITAK0tL6fj3Ghi3hJQhNIP8xahg== X-Google-Smtp-Source: ABdhPJwwBH9zXdUYAnaJBWPnWbHiNbfLcB1X1AwG7D4qKSiW0nnK/miv4vVx+LXsXpfUUiKKAaBv8iBsc+pPdD/oPsA= X-Received: by 2002:aca:b843:: with SMTP id i64mr14569342oif.109.1638611457909; Sat, 04 Dec 2021 01:50:57 -0800 (PST) MIME-Version: 1.0 References: <00000000000069924b05c8cc3b84@google.com> <000000000000b7e3ee05d21bd19d@google.com> <20211201210938.GL641268@paulmck-ThinkPad-P17-Gen-1> In-Reply-To: <20211201210938.GL641268@paulmck-ThinkPad-P17-Gen-1> From: Dmitry Vyukov Date: Sat, 4 Dec 2021 10:50:47 +0100 Message-ID: Subject: Re: [syzbot] WARNING in trc_read_check_handler To: paulmck@kernel.org Cc: syzbot , 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 Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 1 Dec 2021 at 22:09, Paul E. McKenney wrote: > > 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 Thanks for checking. If we don't have one exact fix, let's go with what syzbot suggested. At this point it does not matter much since all of them are in most trees I assume. We just need to close the bug with something. #syz fix: rcu-tasks: Simplify trc_read_check_handler() atomic operations > Quibbles aside, it is nice to get an automated email about having fixed > a bug as opposed to having added one. ;-) Yes, but one is not possible without the other :-)