From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from nautica.notk.org (nautica.notk.org [91.121.71.147]) (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 98D9E3D6C for ; Wed, 15 Nov 2023 07:15:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=codewreck.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b="ih3Vmn8D"; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b="Lr8X1VL+" Received: by nautica.notk.org (Postfix, from userid 108) id EE544C009; Wed, 15 Nov 2023 08:07:03 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1700032023; bh=XeRLQ/ZbHAhANYJbae35MvxoExBCZAaYiuVIDO+z5XU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ih3Vmn8D/uBdgYnvi+7m+l6Pp0pxyHIjmjKKpfmhPv9WrL5OTnl1LdNlSK/IBhMHO AVkqIETpPyAtc17CY3fFMwYUDB2P1gKRlQI77TWFqkVxHtTFEilFTw2YciqZD/FWsv un5gvIZ51w6TmpXVF9RPNxf34Q7EZdb+8eYb1ZWMk7Od8FU8wyu+wjV9DQg9wwPVvR zOUapwHYpVV31T3FkQH78v5RzAm1n9FGMVT/umS5O0LOeH7rRoqCUN3Mr3m24Ur2/e ooJLj9F7uVNeKmGFnOhoo/gGQtYd0MVQ9V9NjASFKAvjYXSPSAhvTyFKU767h7l1pu VLWEzUOvC3FRQ== X-Spam-Level: Received: from gaia (localhost [127.0.0.1]) by nautica.notk.org (Postfix) with ESMTPS id 12B74C009; Wed, 15 Nov 2023 08:07:01 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1700032022; bh=XeRLQ/ZbHAhANYJbae35MvxoExBCZAaYiuVIDO+z5XU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Lr8X1VL+SGwAvhkZLLHdA8XM2j/wkI+oons8D1Qk4LnwYsbj3nOA4CAXQXkpFHqgC V6CVsDz2cgdRKsasq9MC7geIfcdCn7SKk2xdw+Ox9+1qyOurhMNCjuceCXzU0ITSBR pQ1HcEmUB9Sxpdzuk3mrS0sYc1HAMeFeF+vYYQoRqPinb30E3gt9hwwvlIi8fznnr4 rXgGJtNX0WAAInmrZfF773BkxwWhHNhuemEvi2zB6NY5IPkGcKF80ZGvYF4x5x+8Z1 XYPuNUm19b/2Wb6AqU+/5E5VuxMQT7at6HARsWe8/ITqic2mNmdbfEzNxQ9DtvgpxL bpQdV0szzYIlA== Received: from localhost (gaia [local]) by gaia (OpenSMTPD) with ESMTPA id d6a5a159; Wed, 15 Nov 2023 07:06:58 +0000 (UTC) Date: Wed, 15 Nov 2023 16:06:43 +0900 From: "asmadeus@codewreck.org" To: Albert Guo Cc: v9fs@lists.linux.dev Subject: Re: [syzbot] WARNING: refcount bug in p9_client_walk Message-ID: References: Precedence: bulk X-Mailing-List: v9fs@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Albert Guo wrote on Wed, Nov 15, 2023 at 03:50:48AM +0000: > Hi Asemadeus, Please always cc the subsystem's mailing list when asking such questions; there's no point in singling out maintainers. (And it'd really help if you wouldn't mispell names; although I guess you could also say it does help since rilled up folks are more likely to answer...) > I’m Albert Guo from VMware. Sorry to disturb you. I’m writing to you to seek some help for Linux 9p driver. > We use 9p driver in our product. We seem to encounter similar refcount issue in our test: > [syzbot] WARNING: refcount bug in p9_client_walk > https://groups.google.com/g/syzkaller-bugs/c/UrvjxOLiykQ/m/LlVAtCzQBQAJ?pli=1 > > syzbot > 2023年3月23日 06:02:37 > > 收件人 syzkall...@googlegroups.com > Auto-closing this bug as obsolete. > No recent activity, existing reproducers are no longer triggering the issue. > > > Looks like the issue isn’t reproducible from syzbot? Is it fixed? Do > you know which commit fix the issue? It might have been fixed in 26273ade77f54716e30dfd40ac6e85ceb54ac0f9 as uninitialized use could be causing that, otherwise I don't know -- there's been no other fix around refcounting since that report... > Our kernel version is 6.1.56: https://elixir.bootlin.com/linux/v6.1.56/source But it's long been fixed (included in 6.2 and 6.1.2), so there must be another problem. Please give your full stack trace (and not just a link to syzbot); the warn message might help. Also, how often do you hit this? (Can we consider it "reproductible" under test where you would be able to run with tracepoints, or simplifying the load etc?) -- Dominique Martinet | Asmadeus