From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa2-f0.google.com (mail-oa2-f0.google.com [74.125.231.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 522D6399CFC for ; Mon, 24 Aug 2026 07:47:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.231.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787557655; cv=none; b=MrC7wHrg9OdKD/pYz/GBKZETfZyJpvqVIM/3yUakueN3e+1Ck1bI8v95gTjW+/AX7WS19SwoDTnq9qzU7rog9zmq8Y7K8fFRzJ71ZLXuIMP3pSvN6Jx2s1fcv7r9Z0c0SOgEQj8dZR99BwfHbinzRzJxay0cdQgaqPPo1uOt3G8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787557655; c=relaxed/simple; bh=uSxWJY8a5CLjZuEErwvpCzXXvGzdqJAZZGIqu/KXbKw=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=ATs9gXnRcYFNKnHf2zu8ylc7xFZrAb30/nzf0iNZHkvFz9hFkeLPcIgDZZeJjKNv7EvECTtOldSf73LjWsjElO+AHNxfjHsbMstDdLFLkDMaDizxuE/64F1sejgzhAfqwviV+xwv88LFq68VVnvnbwyKoJvoBeg2Cl4GG55WKGE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=74.125.231.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oa2-f0.google.com with SMTP id 586e51a60fabf-44cdbcd53b8so201052fac.0 for ; Mon, 24 Aug 2026 00:47:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787557653; x=1788162453; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=rdFTXNKdZnj8wRa0kB+fQ1jCWh5iT/QDPNx/L7O9Mtg=; b=jBPhqeQKdp0KaTc7BQdKH4Zk2v0gB+Uu3ZVtwvcd3Dxa2L+bXWEcul69+8kIcFKFzI dk8859G2aLpc1BCYDRIjko+v+JyynvF/jSDOHXLfTVKeDMCXhkvI0qlC5Ox3Zl1byHVM pdhHXnWg2qNYq/z8TF52WBTWenBOHsRCvKV1Qj/nEvR/ZMqhmHAMN0SnGd5aF6NbUuHs /R5tzpAaqtd30ZSkHsQFW1fCbinWBhtTLkjFhjtkITSq+bTeJI81r1A2clojJDze2nn9 3MbXqvMJ0k8BY7Iwjgs16g++8himvcLL8vDEi/rYwXAIG1JUEVXSNY1fN0RdY8ATSawC 6tig== X-Forwarded-Encrypted: i=1; AHgh+RpIugiM8axodJXOV/Y5zoPmi2hLnQ0WfFm6nsJ/Im+uHmWZIcjEGVsTBbf9KGTHef5C4uqvEe9WBt9BLTA=@vger.kernel.org X-Gm-Message-State: AFuF++kZdKO4gRePL0O/e1n7MNBetrUsu4ec1w58uoR59aeLJnCzHWeJ fiR196uQ4cGCX0Q4Pqk85ku/A1g2qmkSJXOxMzdy6AYC1iDbnf32p0vdmVvrV8T9T1HQB+BGawd umpkhKcOvl1DJOV95QCOUfyc+0Dor/xQNcYsITNO8RsICowXN7F9BJFO7fmg= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:c1ba:b0:495:ce61:4e0c with SMTP id 5614622812f47-4b309a0034bmr14802496b6e.3.1787557653158; Mon, 24 Aug 2026 00:47:33 -0700 (PDT) Date: Mon, 24 Aug 2026 00:47:33 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a8bf715.dbb3a75c.13dd47.0065.GAE@google.com> Subject: [syzbot] [exfat?] WARNING in fat_ent_write From: syzbot To: hirofumi@mail.parknet.co.jp, linkinjeon@kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, sj1557.seo@samsung.com, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 6a746cd265ae Add linux-next specific files for 20260819 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=13cdee79580000 kernel config: https://syzkaller.appspot.com/x/.config?x=4a1369648c551bbe dashboard link: https://syzkaller.appspot.com/bug?extid=26461e903494e689c24f compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17760e79580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/32d71a199871/disk-6a746cd2.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/7bfb88f0043e/vmlinux-6a746cd2.xz kernel image: https://storage.googleapis.com/syzbot-assets/4bc2ab35db01/bzImage-6a746cd2.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/500a74ccb5d4/mount_0.gz fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=17e3d679580000) IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+26461e903494e689c24f@syzkaller.appspotmail.com and is ignored by this kernel. Remove the mand option from the mount to silence this warning. ======================================================= Buffer I/O error on dev loop0, logical block 1, lost sync page write ------------[ cut here ]------------ !buffer_uptodate(bh) WARNING: fs/buffer.c:991 at mark_buffer_dirty+0x299/0x410 fs/buffer.c:991, CPU#1: syz.0.17/5854 Modules linked in: CPU: 1 UID: 0 PID: 5854 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:mark_buffer_dirty+0x299/0x410 fs/buffer.c:991 Code: 4c 89 f7 e8 09 0a d8 ff 49 8b 3e be 40 00 00 00 5b 41 5c 41 5e 41 5f 5d e9 74 52 fb ff e8 4f 40 68 ff eb 8c e8 48 40 68 ff 90 <0f> 0b 90 e9 a5 fd ff ff e8 3a 40 68 ff 90 0f 0b 90 e9 cf fd ff ff RSP: 0018:ffffc9000345f2d0 EFLAGS: 00010293 RAX: ffffffff825f7f28 RBX: ffff8880714019a0 RCX: ffff8880317c5dc0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002 RBP: dffffc0000000001 R08: ffff8880714019a7 R09: 1ffff1100e280334 R10: dffffc0000000000 R11: ffffed100e280335 R12: ffffffff8c288c60 R13: ffff888032a9c248 R14: dffffc0000000000 R15: ffff8880717c46a8 FS: 00007fc05a3146c0(0000) GS:ffff888124dda000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9293991000 CR3: 000000007992c000 CR4: 00000000003526f0 Call Trace: mmb_mark_buffer_dirty+0x2c/0x1f0 fs/buffer.c:624 fat_ent_write+0xb8/0x190 fs/fat/fatent.c:422 fat_chain_add+0x409/0x8e0 fs/fat/misc.c:140 fat_add_cluster fs/fat/inode.c:113 [inline] __fat_get_block fs/fat/inode.c:155 [inline] fat_get_block+0x768/0xae0 fs/fat/inode.c:190 __block_write_begin_int+0x6c2/0x1900 fs/buffer.c:2030 block_write_begin fs/buffer.c:2144 [inline] cont_write_begin+0x71b/0xac0 fs/buffer.c:2506 fat_write_begin+0x7a/0x150 fs/fat/inode.c:230 cont_expand_zero fs/buffer.c:2434 [inline] cont_write_begin+0x2d6/0xac0 fs/buffer.c:2496 fat_write_begin+0x7a/0x150 fs/fat/inode.c:230 generic_perform_write+0x2d5/0x8f0 mm/filemap.c:4374 generic_file_write_iter+0xae/0x330 mm/filemap.c:4517 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x612/0xba0 fs/read_write.c:687 ksys_pwrite64 fs/read_write.c:794 [inline] __do_sys_pwrite64 fs/read_write.c:802 [inline] __se_sys_pwrite64 fs/read_write.c:799 [inline] __x64_sys_pwrite64+0x196/0x220 fs/read_write.c:799 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc05939e0d9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fc05a314028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012 RAX: ffffffffffffffda RBX: 00007fc059625fa0 RCX: 00007fc05939e0d9 RDX: 000000000000fdef RSI: 0000200000000140 RDI: 0000000000000004 RBP: 00007fc059435024 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000fecc R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc059626038 R14: 00007fc059625fa0 R15: 00007fff03653f68 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup