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[2620:137:e000::1:20]) by mx.google.com with ESMTP id b13-20020a056402084d00b0042dd2f1949dsi15042904edz.511.2022.06.06.19.54.43; Mon, 06 Jun 2022 19:55:09 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linux-foundation.org header.s=korg header.b=vxc6V+aP; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232252AbiFFTXS (ORCPT + 99 others); Mon, 6 Jun 2022 15:23:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232266AbiFFTXH (ORCPT ); Mon, 6 Jun 2022 15:23:07 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F2357666 for ; Mon, 6 Jun 2022 12:23:04 -0700 (PDT) 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 0D06961464 for ; Mon, 6 Jun 2022 19:23:04 +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-Spam-Status: No, score=-10.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,RCVD_IN_DNSWL_HI, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (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.