From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f198.google.com (mail-oi1-f198.google.com [209.85.167.198]) (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 4DB1830B514 for ; Sun, 1 Mar 2026 17:40:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.198 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772386833; cv=none; b=Sccp1fI0gomzdfEJRz8rxIIzjYkMR769Px+gCeL7Z6GxgXfh5yhj3gvmg6XUCVAgg+6pcisQPRHF/3NlQ4ZGp2PBoG1VTVy71b2Vx0Qs6xo3qW8pYxfiIt6ux0oGehGAAMhr9gn1OP6nNr0z4xCnU9ALo1N8hqV3PjzTuvtSypY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772386833; c=relaxed/simple; bh=c2AMNUmcL6ZVHG+nGRVd2R0Fvdz/nVNFA0bmNMjkJEk=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=keMjhIlMhbQ45D+QVvhb4IBIk3A/TUCiJvTpzEt4ltkDO9Z6GyVZEhCvDp4SjIblqZpG79CPawL9RIoJrG7QZLNfXJKlByqbD2VuRxENnUwRAxvCNWr60Xf/RagQnSHLWnKgQxuB7IL/EGR+I7QYZlARP934z0dSUfWWaPMuVtw= 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=209.85.167.198 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-oi1-f198.google.com with SMTP id 5614622812f47-463c4133ccaso48782096b6e.2 for ; Sun, 01 Mar 2026 09:40:32 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772386831; x=1772991631; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=rqF6YfiVtI9PUPl6zKaf/kpEamc4fPsUxjwnl79XGXA=; b=teqO7xPEaeMuLibQ1Wa+91YZVpVajR2ZyQdyOHt3pDp5VqqAzzLrf0VjDX5FuZ5jHo K3GrC3x+TU5ZCmDU3wtTjKlmZazQ0mpUhRvQ/p8/5Vw1kiCx7xUArxNt7/xfKiTjOSGm fGcxQkMIa9v97/VD1r9dEB/TaWmFPGHs5D3vAOxgkjUFIz1HSsb68cDb+jF5p39VV298 rtsQsomlFYg+ar1Op+Bz1zq5Zv5oyR4VEBhWhO2Ilpv7i66qOBgKg+skj97wG1bZBFnH iPL1EozV0mA8OMpIFSrV/oXJDQIMf9GfVvLSezuTe4iM1xs/qD9UAFSm4KSC8jqNLsy/ OKlg== X-Forwarded-Encrypted: i=1; AJvYcCWTgk4TF4NULQV0rEFlZ+0qNHRqwPnC20PHQeU20lpRQFpusIvSDdWsbPyaPIkmwsXldE2Bpux+AhvW@vger.kernel.org X-Gm-Message-State: AOJu0YwUl8aCOHqP6pz0PyTd2ar4O2Z+cfgEjF+jbQ4gDfZvI/YTrZxF rdwoOXUAYGgca2aor0ZX6tkNemCHc5ILSaAY73j2UGyQlOKSZeEbklMZRBC6fdkHP/JLxMvepjE lVPvISjz+/jqOYFONP2uUEU1oooAHg3wpnOJzMUi3fppOQ7fQjZS8aHjY56w= Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:4988:b0:662:f763:c539 with SMTP id 006d021491bc7-679fadb7a4amr4755094eaf.14.1772386831234; Sun, 01 Mar 2026 09:40:31 -0800 (PST) Date: Sun, 01 Mar 2026 09:40:31 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69a47a0f.050a0220.3a55be.0065.GAE@google.com> Subject: [syzbot] [ext4?] kernel BUG in ext4_ext_map_blocks From: syzbot To: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, tytso@mit.edu Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 7dff99b35460 Remove WARN_ALL_UNSEEDED_RANDOM kernel config.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1749955a580000 kernel config: https://syzkaller.appspot.com/x/.config?x=70fe0401f305d8d4 dashboard link: https://syzkaller.appspot.com/bug?extid=b20d00cf1ba477ac419f compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/f33ddab53df8/disk-7dff99b3.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/3c50676d2681/vmlinux-7dff99b3.xz kernel image: https://storage.googleapis.com/syzbot-assets/bbae16d525e0/bzImage-7dff99b3.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+b20d00cf1ba477ac419f@syzkaller.appspotmail.com EXT4-fs (loop9): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback. ------------[ cut here ]------------ kernel BUG at fs/ext4/ext4_extents.h:193! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 0 UID: 0 PID: 8704 Comm: syz.9.339 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:ext4_ext_mark_unwritten fs/ext4/ext4_extents.h:193 [inline] RIP: 0010:ext4_ext_map_blocks+0x5521/0x58b0 fs/ext4/extents.c:4453 Code: 06 af ff ff e8 b0 5a 4e ff 48 c7 c7 80 d6 e2 8d be 04 00 00 00 e8 5f e1 32 ff 65 48 ff 43 08 e9 e6 ae ff ff e8 90 5a 4e ff 90 <0f> 0b e8 88 5a 4e ff 90 0f 0b e8 80 5a 4e ff 90 0f 0b e8 78 5a 4e RSP: 0018:ffffc9001238ef60 EFLAGS: 00010283 RAX: ffffffff8275f850 RBX: 0000000000000000 RCX: 0000000000080000 RDX: ffffc90006f92000 RSI: 000000000000d48e RDI: 000000000000d48f RBP: ffffc9001238f240 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: fffffbfff1ed44b7 R12: 1ffff92002471e1c R13: 0000000000000003 R14: 00000000000001c1 R15: 0000000000000000 FS: 0000[ 298.651065][ T8704] FS: 00007f0b370f66c0(0000) GS:ffff888126343000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0b2ece1000 CR3: 0000000040192000 CR4: 00000000003526f0 Call Trace: ext4_map_create_blocks+0x11d/0x540 fs/ext4/inode.c:616 ext4_map_blocks+0x7cd/0x11d0 fs/ext4/inode.c:809 _ext4_get_block+0x1e3/0x470 fs/ext4/inode.c:909 ext4_get_block_unwritten+0x2e/0x100 fs/ext4/inode.c:942 ext4_block_write_begin+0xb14/0x1950 fs/ext4/inode.c:1196 ext4_write_begin+0xb40/0x18c0 fs/ext4/ext4_jbd2.h:-1 ext4_da_write_begin+0x355/0xd90 fs/ext4/inode.c:3123 generic_perform_write+0x2af/0x8b0 mm/filemap.c:4314 ext4_buffered_write_iter+0xd0/0x3a0 fs/ext4/file.c:300 ext4_file_write_iter+0x299/0x1c10 fs/ext4/file.c:-1 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x629/0xba0 fs/read_write.c:688 ksys_pwrite64 fs/read_write.c:795 [inline] __do_sys_pwrite64 fs/read_write.c:803 [inline] __se_sys_pwrite64 fs/read_write.c:800 [inline] __x64_sys_pwrite64+0x19c/0x230 fs/read_write.c:800 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0b38e9c629 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:00007f0b370f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012 RAX: ffffffffffffffda RBX: 00007f0b39115fa0 RCX: 00007f0b38e9c629 RDX: 000000000000fdef RSI: 0000200000000140 RDI: 0000000000000007 RBP: 00007f0b38f32b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000c00 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0b39116038 R14: 00007f0b39115fa0 R15: 00007ffd1d3115a8 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:ext4_ext_mark_unwritten fs/ext4/ext4_extents.h:193 [inline] RIP: 0010:ext4_ext_map_blocks+0x5521/0x58b0 fs/ext4/extents.c:4453 Code: 06 af ff ff e8 b0 5a 4e ff 48 c7 c7 80 d6 e2 8d be 04 00 00 00 e8 5f e1 32 ff 65 48 ff 43 08 e9 e6 ae ff ff e8 90 5a 4e ff 90 <0f> 0b e8 88 5a 4e ff 90 0f 0b e8 80 5a 4e ff 90 0f 0b e8 78 5a 4e RSP: 0018:ffffc9001238ef60 EFLAGS: 00010283 RAX: ffffffff8275f850 RBX: 0000000000000000 RCX: 0000000000080000 RDX: ffffc90006f92000 RSI: 000000000000d48e RDI: 000000000000d48f RBP: ffffc9001238f240 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: fffffbfff1ed44b7 R12: 1ffff92002471e1c R13: 0000000000000003 R14: 00000000000001c1 R15: 0000000000000000 FS: 00007f0b370f66c0(0000) GS:ffff888126443000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0b2ece7000 CR3: 0000000040192000 CR4: 00000000003526f0 --- 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 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