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=-5.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 645E5C433E1 for ; Wed, 10 Jun 2020 21:56:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 44B9E20814 for ; Wed, 10 Jun 2020 21:56:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726496AbgFJV4F (ORCPT ); Wed, 10 Jun 2020 17:56:05 -0400 Received: from mail-io1-f69.google.com ([209.85.166.69]:38146 "EHLO mail-io1-f69.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726303AbgFJV4F (ORCPT ); Wed, 10 Jun 2020 17:56:05 -0400 Received: by mail-io1-f69.google.com with SMTP id l19so2521045iol.5 for ; Wed, 10 Jun 2020 14:56:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:in-reply-to:message-id:subject :from:to; bh=zPzq8Z3GKSk3UIRzJdOGFkl1eD/aaIDkUJNbvpb5G54=; b=SJY+cTflqfOEDqOx0KH6Wg16mWlERO2CL0ot6vN1o63fyNBc8k2grmEp/V5ogLOx1j DZJc5d9omd0AnpeeRnjAq1yCuRYV21cvRr2RlAERmP2sAZHWMYdRVkb3fcCfLqbeexdY PjNqJrHvH6rUuzR2HhLhIJf5lOM+zao21eNCm+F1ItBpykGzCjOPFOiuhBLXrdt8zyc9 bLiNmdyRHb2CBm5UxiGC/Bi2ntDzipGJh8jxE7sh4tt8fACX9G51TcXFLD9NKIXbeWtj IRXqOLe8dRzw4DC2rZVYbezUsn9bA6OstGNjNeGbtFfVT/gqNzarFIDP6pQ6uRRUpN5C 54Rg== X-Gm-Message-State: AOAM533Qp3kpf7N1umhf69gt5DZprG73oV1SJS04FVZIZAMp2vFFOs9p lV1AzEA78MNNYjIpjWhXjqcGsBXZCTCAIXJCTEewobLkffoo X-Google-Smtp-Source: ABdhPJwdkWvMBc1TJXeW0mgdyMOWPQe+AxeV8HWhb/kgzkEPdNlxjttn1vdto1D35yO45FopICQEQGsF9FDHXLO3hZla1CRUNIII MIME-Version: 1.0 X-Received: by 2002:a92:c6c5:: with SMTP id v5mr3414047ilm.1.1591826163957; Wed, 10 Jun 2020 14:56:03 -0700 (PDT) Date: Wed, 10 Jun 2020 14:56:03 -0700 In-Reply-To: <20200610214107.GK1347934@mit.edu> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000000c06da05a7c1e93d@google.com> Subject: Re: BUG: unable to handle kernel NULL pointer dereference in generic_perform_write (2) From: syzbot To: adilger.kernel@dilger.ca, akpm@linux-foundation.org, dan.j.williams@intel.com, jack@suse.cz, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, tytso@mit.edu Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot has tested the proposed patch but the reproducer still triggered crash: BUG: unable to handle kernel NULL pointer dereference in generic_perform_write BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page PGD a3819067 P4D a3819067 PUD a2ea0067 PMD 0 Oops: 0010 [#1] PREEMPT SMP KASAN CPU: 1 PID: 9214 Comm: syz-executor.1 Not tainted 5.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:0x0 Code: Bad RIP value. RSP: 0018:ffffc90006d1fa38 EFLAGS: 00010246 RAX: ffffffff883cb0a0 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffff888082b89a60 RDI: ffff88808a414a80 RBP: ffff888082b89a60 R08: 0000000000000000 R09: ffffc90006d1fac0 R10: ffff888072cd6607 R11: ffffed100e59acc0 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000000 R15: ffffc90006d1fd18 FS: 00007f310f3f3700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 00000000904f1000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: generic_perform_write+0x20a/0x4e0 mm/filemap.c:3302 ext4_buffered_write_iter+0x1f7/0x450 fs/ext4/file.c:270 ext4_file_write_iter+0x1ec/0x13f0 fs/ext4/file.c:642 call_write_iter include/linux/fs.h:1907 [inline] new_sync_write+0x4a2/0x700 fs/read_write.c:484 __vfs_write+0xc9/0x100 fs/read_write.c:497 vfs_write+0x268/0x5d0 fs/read_write.c:559 ksys_write+0x12d/0x250 fs/read_write.c:612 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c889 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f310f3f2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f310f3f36d4 RCX: 000000000045c889 RDX: 0000000000000001 RSI: 0000000020000080 RDI: 0000000000000003 RBP: 000000000076bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000cdc R14: 00000000004cf042 R15: 000000000076bfac Modules linked in: CR2: 0000000000000000 ---[ end trace ff42a65b331528ba ]--- RIP: 0010:0x0 Code: Bad RIP value. RSP: 0018:ffffc90006d1fa38 EFLAGS: 00010246 RAX: ffffffff883cb0a0 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffff888082b89a60 RDI: ffff88808a414a80 RBP: ffff888082b89a60 R08: 0000000000000000 R09: ffffc90006d1fac0 R10: ffff888072cd6607 R11: ffffed100e59acc0 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000000 R15: ffffc90006d1fd18 FS: 00007f310f3f3700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000076c061 CR3: 00000000904f1000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Tested on: commit: 5b8b9d0c Merge branch 'akpm' (patches from Andrew) git tree: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git console output: https://syzkaller.appspot.com/x/log.txt?x=158b23ca100000 kernel config: https://syzkaller.appspot.com/x/.config?x=23c5a352e32a1944 dashboard link: https://syzkaller.appspot.com/bug?extid=bca9799bf129256190da compiler: gcc (GCC) 9.0.0 20181231 (experimental)