From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail115-95.sinamail.sina.com.cn (mail115-95.sinamail.sina.com.cn [218.30.115.95]) (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 3F2711B87FF for ; Sat, 4 Jan 2025 00:01:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=218.30.115.95 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735948892; cv=none; b=cXp4k4MouMhCp642VzAVLYLbOpeRY+ODx4c4MKfWFZvdBY0UQ0W735abtwKiSrsoKRGfNEAdhyiwjULI8sIwyOfFO1/f4/8pFQWEhfdwGuDnQTfjfSfwxUlAikAP7EX3MHHgUiSz41wfQXXAnGkAsEx+Mr6b1PRh9xeEQDNNN2I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735948892; c=relaxed/simple; bh=iL+QhY2jGfSA1QdIPfyZCmOe9KlDNCylLsaSMZgAp24=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=p9xoAvBdwWal81l3k2j5o9SV4z2Td/R8zsH/Nd00WGpr2KIDmDm1jJWJvZ4if01zuaQnjSTcG7H1exqu+bGAhW8KfbxoE1LKKarha3LJ6qJzAViIy/GZQjvMIH+YRLC6vpUFdyyerqAMniFuZ7l9VH9l6f+kOcO6A4ofTO+OKSk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; arc=none smtp.client-ip=218.30.115.95 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com X-SMAIL-HELO: localhost.localdomain Received: from unknown (HELO localhost.localdomain)([113.88.50.58]) by sina.com (10.185.250.23) with ESMTP id 67787A2B00003212; Sat, 4 Jan 2025 08:00:46 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=hdanton@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=hdanton@sina.com X-SMAIL-MID: 5457368913392 X-SMAIL-UIID: 3FDCAF96B6FE48F9873ED17E530CF1E0-20250104-080046-1 From: Hillf Danton To: "Liam R. Howlett" Cc: syzbot , Vladimir Oltean , linux-kernel@vger.kernel.org, linux-mm@kvack.org, lorenzo.stoakes@oracle.com, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [mm?] INFO: rcu detected stall in mas_preallocate (2) Date: Sat, 4 Jan 2025 08:00:33 +0800 Message-ID: <20250104000035.1356-1-hdanton@sina.com> In-Reply-To: References: <6756b479.050a0220.a30f1.0196.GAE@google.com> <6777334a.050a0220.3a8527.0058.GAE@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Fri, 3 Jan 2025 10:20:34 -0500 "Liam R. Howlett" > * syzbot [250102 19:47]: > > syzbot has bisected this issue to: > > > > commit 5a781ccbd19e4664babcbe4b4ead7aa2b9283d22 > > Author: Vinicius Costa Gomes > > Date: Sat Sep 29 00:59:43 2018 +0000 > > > > tc: Add support for configuring the taprio scheduler > > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=117df818580000 > > start commit: feffde684ac2 Merge tag 'for-6.13-rc1-tag' of git://git.ker.. > > git tree: upstream > > final oops: https://syzkaller.appspot.com/x/report.txt?x=137df818580000 > > console output: https://syzkaller.appspot.com/x/log.txt?x=157df818580000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=50c7a61469ce77e7 > > dashboard link: https://syzkaller.appspot.com/bug?extid=882589c97d51a9de68eb > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10e8a8df980000 > > > > Reported-by: syzbot+882589c97d51a9de68eb@syzkaller.appspotmail.com > > Fixes: 5a781ccbd19e ("tc: Add support for configuring the taprio scheduler") > > > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > > > > This looks wrong, if this is a bug (which looks like it is since it has > a syzbot reproducer?), then it's different than the previous two reports > and probably not related. > In case you missed it, take a look at https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fb66df20a720 > > Vinicius, > > Looking at the patch, it seems you missed some users of -1 vs > TAPRIO_ALL_GATES_OPEN in taprio_peek(). The comment in taprio_dequeue() > is useful - maybe the gate_mask rcu lock/unlock could be a function and > have that comment live in a static inline function? > > Thanks, > Liam