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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id ACD29C43334 for ; Mon, 6 Jun 2022 19:23:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4EA2B6B0072; Mon, 6 Jun 2022 15:23:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 499E06B0073; Mon, 6 Jun 2022 15:23:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 389D36B0078; Mon, 6 Jun 2022 15:23:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 254EE6B0072 for ; Mon, 6 Jun 2022 15:23:05 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 0266720B8A for ; Mon, 6 Jun 2022 19:23:04 +0000 (UTC) X-FDA: 79548783930.24.5D46C65 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf08.hostedemail.com (Postfix) with ESMTP id D3BF3160048 for ; Mon, 6 Jun 2022 19:22:35 +0000 (UTC) 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 dfw.source.kernel.org (Postfix) with ESMTPS id AAD496140F; Mon, 6 Jun 2022 19:23:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4EB23C385A9; Mon, 6 Jun 2022 19:23:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1654543383; bh=nacxubDqFFdRgVSLGS1ry36IABpXpVQprcKZtbeliOs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=vxc6V+aPGyj7IZtXMPWd1wyKdJMKJdmLb7acJqI0wxdZlPloE6DcXfTYfaMS6KsuH Em6FW1FQD/p6GKuD6O8eB4GpbhxYIA5agMKnG0TNMJ03YXL1Qwspd4g9FqenQpMYmi dyPUFe8xBgubXXb/spABHk4+oElZS+nPa1xODKOE= Date: Mon, 6 Jun 2022 12:23:02 -0700 From: Andrew Morton To: syzbot Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, Roman Gushchin Subject: Re: [syzbot] WARNING in register_shrinker_prepared Message-Id: <20220606122302.dc265509ca896073e98049a3@linux-foundation.org> In-Reply-To: <000000000000db448c05e0caa5ba@google.com> References: <000000000000db448c05e0caa5ba@google.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: D3BF3160048 X-Stat-Signature: 7g7ghb4cyb1gta9gbpas8w3b3c8wqt4r X-Rspam-User: Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=vxc6V+aP; spf=pass (imf08.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-HE-Tag: 1654543355-931337 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: (cc Roman) On Mon, 06 Jun 2022 10:17:34 -0700 syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 1cfd968b58a1 Add linux-next specific files for 20220603 > git tree: linux-next > console+strace: https://syzkaller.appspot.com/x/log.txt?x=12f7b6b3f00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=7da8386e3742814f > dashboard link: https://syzkaller.appspot.com/bug?extid=300d27c79fe6d4cbcc39 > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=103e5177f00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13545057f00000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+300d27c79fe6d4cbcc39@syzkaller.appspotmail.com > > loop0: detected capacity change from 0 to 20 > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 3694 at mm/vmscan.c:681 register_shrinker_prepared+0x119/0x150 mm/vmscan.c:681 That's WARN_ON_ONCE(shrinker_debugfs_add(shrinker)); I assume that debugfs_create_dir() failed. Please see the NOTE: in that function's kerneldoc.