From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.parknet.co.jp (mail.parknet.co.jp [210.171.160.6]) (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 07A05369D74; Mon, 24 Aug 2026 09:31:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=210.171.160.6 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787563902; cv=none; b=KQDeaspHlpn4ADc4ln+AJ5SOxYV91dEi7HWN9bHuv1ChBfIMF3rz4bzElhjZbRp3MWN+wqT/p2WxCPwKZ9fHNPW7o65s5gd9nYPtx561PA++GHZTchDAqU22bAVTMKBarpWkF9KHnaS6eoMRCsjj9MrACA8fOrCZDpZ+c/VwsL4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787563902; c=relaxed/simple; bh=xNNoyyzorQwzXZswV/S9IsKwLv1PWe1gfb87d67l/aU=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=Ym3fgqqgLOMq/2sgjmbZUbMT8Ty1fsIpo8+NEOu5UAjxj5XhGVxcPcnulecQL7avDVqxDA6mXIlXbWd0/Eqr22DASb2SKiXKVr8wlKJUau76oPhJPdwvs/a2LHU0/x0qO0hoFbrcrnEvAHkNLO+KbbW7NVbiPGiqnDCC7yyecJk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mail.parknet.co.jp; spf=pass smtp.mailfrom=parknet.co.jp; dkim=pass (2048-bit key) header.d=parknet.co.jp header.i=@parknet.co.jp header.b=dg/vEm5+; dkim=permerror (0-bit key) header.d=parknet.co.jp header.i=@parknet.co.jp header.b=e3LRWN1g; arc=none smtp.client-ip=210.171.160.6 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mail.parknet.co.jp Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=parknet.co.jp Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=parknet.co.jp header.i=@parknet.co.jp header.b="dg/vEm5+"; dkim=permerror (0-bit key) header.d=parknet.co.jp header.i=@parknet.co.jp header.b="e3LRWN1g" Received: from ibmpc.myhome.or.jp (server.parknet.ne.jp [210.171.168.39]) by mail.parknet.co.jp (Postfix) with ESMTPSA id 7866526F765F; Mon, 24 Aug 2026 18:31:30 +0900 (JST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=parknet.co.jp; s=20250114; t=1787563890; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=VjOFKDBaeWfHcp8XWnUq9Necguz8vdzoJtC88sHQZFQ=; b=dg/vEm5+wKcLObk7RCAauvWr8ovCMh6sG4jeXjHg4cNSqdViN8wrLFUGzeY9O+3HSO49bd f0r0e9A/6GX0Hq2Ozrtjjgfk3ekgw0Lro1dO6E7k7WZMQeEjDgWnd8zTNjcCh3A5uaJBz0 /FPA9vk/oDOnfYgbvUCbqNDucIWAJBHAcG4wi6sH0/LiIpkDPS8wz3vpQDHcw2b3fcCZSe kfLou8ZWMzkWBwp3etYkGgGmEnEdpfo7SXCYshNvHRZYgE9QLqXeKj5zNssLRdym0FYPs3 WBeMqQ+x6/7hyCX0w/vWv1K9dLjM+DXAj3tEL83IS2PAOwLUvaH8GS2JeKbQ4w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=parknet.co.jp; s=20250114-ed25519; t=1787563890; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=VjOFKDBaeWfHcp8XWnUq9Necguz8vdzoJtC88sHQZFQ=; b=e3LRWN1gINigFK24Q515uRVlHHZdZ1osrpT8htEM6T6GyV58mYN6gVcvRRUGCXDJHgZ+FV Bgw8eGce1qco1cBQ== Received: from devron.myhome.or.jp (devron.myhome.or.jp [192.168.0.3]) by ibmpc.myhome.or.jp (Postfix) with ESMTPS id F3412E001BC; Mon, 24 Aug 2026 18:31:29 +0900 (JST) Received: by devron.myhome.or.jp (Postfix, from userid 1000) id E961A22000D2; Mon, 24 Aug 2026 18:31:29 +0900 (JST) From: OGAWA Hirofumi To: Andrew Morton Cc: linkinjeon@kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, sj1557.seo@samsung.com, syzkaller-bugs@googlegroups.com Subject: Re: Please drop 64d9183203eeb in mm-nonmm-unstable ([syzbot] [exfat?] WARNING in fat_ent_write) In-Reply-To: <6a8bf715.dbb3a75c.13dd47.0065.GAE@google.com> References: <6a8bf715.dbb3a75c.13dd47.0065.GAE@google.com> Date: Mon, 24 Aug 2026 18:31:29 +0900 Message-ID: <875x0z6f0u.fsf@mail.parknet.co.jp> User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/commit/fs/fat/misc.c?h=mm-nonmm-unstable&id=64d9183203eebe33de6188b70a8c1e91f52885db (fat: restore original value when fat_ent_write failed) This commit was missing to consider about the path of error by sync write. Since current bh write clears uptodate flag if got I/O error, so this patch doesn't work for now with wait==true. Please drop this patch at least until stop clearing the uptodate by bh sync write and buffer is reusable after the error. Thanks. syzbot writes: > 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 -- OGAWA Hirofumi