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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C6C50CA9EBB for ; Thu, 24 Oct 2019 10:09:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9D06120663 for ; Thu, 24 Oct 2019 10:09:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393242AbfJXKJC (ORCPT ); Thu, 24 Oct 2019 06:09:02 -0400 Received: from www262.sakura.ne.jp ([202.181.97.72]:54102 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2393241AbfJXKJC (ORCPT ); Thu, 24 Oct 2019 06:09:02 -0400 Received: from fsav403.sakura.ne.jp (fsav403.sakura.ne.jp [133.242.250.102]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id x9OA8tth056753; Thu, 24 Oct 2019 19:08:55 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav403.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav403.sakura.ne.jp); Thu, 24 Oct 2019 19:08:55 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav403.sakura.ne.jp) Received: from [192.168.1.8] (softbank126227201116.bbtec.net [126.227.201.116]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id x9OA8n86056449 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NO); Thu, 24 Oct 2019 19:08:54 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Subject: Re: INFO: task syz-executor can't die for more than 143 seconds. (2) To: axboe@kernel.dk References: <000000000000c52dbf05958f3f3a@google.com> Cc: syzbot , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com From: Tetsuo Handa Message-ID: <3fbc4bb2-a03b-fbfa-4803-47a6d0075ff2@I-love.SAKURA.ne.jp> Date: Thu, 24 Oct 2019 19:08:48 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <000000000000c52dbf05958f3f3a@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 2019/10/23 16:56, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: c4b9850b Add linux-next specific files for 20191018 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=177b3ab0e00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=c940ef12efcd1ec > dashboard link: https://syzkaller.appspot.com/bug?extid=b48daca8639150bc5e73 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1356b8ff600000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14f48687600000 The reproducer is trying to allocate 64TB of disk space on /dev/nullb0 using fallocate() but __blkdev_issue_zero_pages() cannot bail out upon SIGKILL (and therefore cannot terminate for minutes). Can we make it killable? I don't know what action is needed for undoing this loop... while (nr_sects != 0) { bio = blk_next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects), gfp_mask); bio->bi_iter.bi_sector = sector; bio_set_dev(bio, bdev); bio_set_op_attrs(bio, REQ_OP_WRITE, 0); while (nr_sects != 0) { sz = min((sector_t) PAGE_SIZE, nr_sects << 9); bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0); nr_sects -= bi_size >> 9; sector += bi_size >> 9; if (bi_size < sz) break; } cond_resched(); }