[syzbot] [ext4?] kernel BUG in ext4_split_extent_at (2)

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syzbot

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Jun 13, 2023, 1:51:54 AM6/13/23
to adilger...@dilger.ca, linux...@vger.kernel.org, linux-...@vger.kernel.org, linux-...@vger.kernel.org, syzkall...@googlegroups.com, ty...@mit.edu
Hello,

syzbot found the following issue on:

HEAD commit: 25041a4c02c7 Merge tag 'net-6.4-rc6' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12801759280000
kernel config: https://syzkaller.appspot.com/x/.config?x=7474de833c217bf4
dashboard link: https://syzkaller.appspot.com/bug?extid=0f4d9f68fb6632330c6c
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11b3bc8d280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/164bca6d1fd9/disk-25041a4c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7522d0748e33/vmlinux-25041a4c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b32318c9ea13/bzImage-25041a4c.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/4bcaa768d65c/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0f4d9f...@syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at fs/ext4/ext4_extents.h:200!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 5141 Comm: syz-executor.2 Not tainted 6.4.0-rc5-syzkaller-00133-g25041a4c02c7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
RIP: 0010:ext4_ext_mark_unwritten fs/ext4/ext4_extents.h:200 [inline]
RIP: 0010:ext4_split_extent_at+0x10f0/0x1100 fs/ext4/extents.c:3221
Code: 4e ac ff 48 8b 54 24 70 48 8b 74 24 60 e9 3b fa ff ff e8 13 77 54 ff 0f 0b e8 0c 77 54 ff 0f 0b e8 c5 85 78 08 e8 00 77 54 ff <0f> 0b e8 f9 76 54 ff 0f 0b e8 f2 76 54 ff 0f 0b 55 41 57 41 56 41
RSP: 0018:ffffc9000432eec0 EFLAGS: 00010293

RAX: ffffffff82370830 RBX: 0000000000000000 RCX: ffff88807d9a9dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000432f028 R08: ffffffff8236fc0c R09: ffffed100eff1db4
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: ffff88801e655d00 R14: 0000000000000000 R15: dffffc0000000000
FS: 00007f6fc7dd5700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002003f000 CR3: 000000007416c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
ext4_split_extent+0x370/0x4e0 fs/ext4/extents.c:3384
ext4_split_convert_extents fs/ext4/extents.c:3713 [inline]
ext4_ext_handle_unwritten_extents fs/ext4/extents.c:3875 [inline]
ext4_ext_map_blocks+0x22c9/0x7210 fs/ext4/extents.c:4167
ext4_map_blocks+0xa4c/0x1cf0 fs/ext4/inode.c:623
ext4_iomap_alloc fs/ext4/inode.c:3298 [inline]
ext4_iomap_begin+0x8e4/0xd30 fs/ext4/inode.c:3348
iomap_iter+0x677/0xec0 fs/iomap/iter.c:91
__iomap_dio_rw+0xe1b/0x22e0 fs/iomap/direct-io.c:597
iomap_dio_rw+0x46/0xa0 fs/iomap/direct-io.c:688
ext4_dio_write_iter fs/ext4/file.c:597 [inline]
ext4_file_write_iter+0x1509/0x1930 fs/ext4/file.c:708
call_write_iter include/linux/fs.h:1868 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x790/0xb20 fs/read_write.c:584
ksys_write+0x1a0/0x2c0 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f6fc708c169
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6fc7dd5168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f6fc71ac050 RCX: 00007f6fc708c169
RDX: 0000000000000012 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00007f6fc70e7ca1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffcf37a297f R14: 00007f6fc7dd5300 R15: 0000000000022000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_ext_mark_unwritten fs/ext4/ext4_extents.h:200 [inline]
RIP: 0010:ext4_split_extent_at+0x10f0/0x1100 fs/ext4/extents.c:3221
Code: 4e ac ff 48 8b 54 24 70 48 8b 74 24 60 e9 3b fa ff ff e8 13 77 54 ff 0f 0b e8 0c 77 54 ff 0f 0b e8 c5 85 78 08 e8 00 77 54 ff <0f> 0b e8 f9 76 54 ff 0f 0b e8 f2 76 54 ff 0f 0b 55 41 57 41 56 41
RSP: 0018:ffffc9000432eec0 EFLAGS: 00010293
RAX: ffffffff82370830 RBX: 0000000000000000 RCX: ffff88807d9a9dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000432f028 R08: ffffffff8236fc0c R09: ffffed100eff1db4
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: ffff88801e655d00 R14: 0000000000000000 R15: dffffc0000000000
FS: 00007f6fc7dd5700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb7c1906000 CR3: 000000007416c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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 syzk...@googlegroups.com.

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If the bug is already fixed, 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
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If you want to change bug's subsystems, reply with:
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(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

syzbot

unread,
Jul 8, 2023, 7:46:00 PM7/8/23
to adilger...@dilger.ca, linux...@vger.kernel.org, linux-...@vger.kernel.org, linux-...@vger.kernel.org, syzkall...@googlegroups.com, ty...@mit.edu
syzbot has found a reproducer for the following issue on:

HEAD commit: 8689f4f2ea56 Merge tag 'mmc-v6.5-2' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12b9cb02a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=7ad417033279f15a
dashboard link: https://syzkaller.appspot.com/bug?extid=0f4d9f68fb6632330c6c
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13977778a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1004666aa80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/21b63023cf5a/disk-8689f4f2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e04836fe057e/vmlinux-8689f4f2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ee05dfd52843/bzImage-8689f4f2.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/e2ab005f1edb/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0f4d9f...@syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at fs/ext4/ext4_extents.h:200!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 5885 Comm: syz-executor219 Not tainted 6.4.0-syzkaller-12365-g8689f4f2ea56 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023
RIP: 0010:ext4_ext_mark_unwritten fs/ext4/ext4_extents.h:200 [inline]
RIP: 0010:ext4_split_extent_at+0xd11/0xe10 fs/ext4/extents.c:3221
Code: e9 d2 f8 ff ff e8 1f 6d 5d ff 66 81 c5 00 80 e9 32 fd ff ff e8 10 6d 5d ff 44 8d bd 00 80 ff ff e9 d1 fc ff ff e8 ff 6c 5d ff <0f> 0b 48 8b 7c 24 18 e8 73 9d b0 ff e9 7f f3 ff ff 48 89 cf e8 46
RSP: 0018:ffffc900055ef268 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88807d9c0000 RSI: ffffffff82277271 RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88807587d00c
R13: 0000000000000000 R14: 0000000000000000 R15: ffff88807587d012
FS: 00007f4820ae9700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4820ae8fe8 CR3: 0000000028105000 CR4: 0000000000350ee0
Call Trace:
<TASK>
ext4_split_extent+0x3fc/0x530 fs/ext4/extents.c:3384
ext4_ext_handle_unwritten_extents fs/ext4/extents.c:3874 [inline]
ext4_ext_map_blocks+0x2e22/0x5bc0 fs/ext4/extents.c:4166
ext4_map_blocks+0x760/0x1890 fs/ext4/inode.c:621
ext4_iomap_alloc fs/ext4/inode.c:3276 [inline]
ext4_iomap_begin+0x43d/0x7a0 fs/ext4/inode.c:3326
iomap_iter+0x446/0x10e0 fs/iomap/iter.c:91
__iomap_dio_rw+0x6e3/0x1d80 fs/iomap/direct-io.c:574
iomap_dio_rw+0x40/0xa0 fs/iomap/direct-io.c:665
ext4_dio_write_iter fs/ext4/file.c:609 [inline]
ext4_file_write_iter+0x1102/0x1880 fs/ext4/file.c:720
call_write_iter include/linux/fs.h:1871 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x981/0xda0 fs/read_write.c:584
ksys_write+0x122/0x250 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f4828f26cd9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 18 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4820ae9208 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000034 RCX: 00007f4828f26cd9
RDX: 0000000000000012 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00007f4828fa4790 R08: 00007f4828fa4798 R09: 00007f4828fa4798
R10: 00007f4828fa4798 R11: 0000000000000246 R12: 00007f4828fa479c
R13: 00007ffef851f96f R14: 00007f4820ae9300 R15: 0000000000022000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_ext_mark_unwritten fs/ext4/ext4_extents.h:200 [inline]
RIP: 0010:ext4_split_extent_at+0xd11/0xe10 fs/ext4/extents.c:3221
Code: e9 d2 f8 ff ff e8 1f 6d 5d ff 66 81 c5 00 80 e9 32 fd ff ff e8 10 6d 5d ff 44 8d bd 00 80 ff ff e9 d1 fc ff ff e8 ff 6c 5d ff <0f> 0b 48 8b 7c 24 18 e8 73 9d b0 ff e9 7f f3 ff ff 48 89 cf e8 46
RSP: 0018:ffffc900055ef268 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88807d9c0000 RSI: ffffffff82277271 RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88807587d00c
R13: 0000000000000000 R14: 0000000000000000 R15: ffff88807587d012
FS: 00007f4820ae9700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffef85799a0 CR3: 0000000028105000 CR4: 0000000000350ee0


---

yebin (H)

unread,
Jul 10, 2023, 11:06:33 AM7/10/23
to syzbot, adilger...@dilger.ca, linux...@vger.kernel.org, linux-...@vger.kernel.org, linux-...@vger.kernel.org, syzkall...@googlegroups.com, ty...@mit.edu
> .
This should be caused by the write block device.
Here's the log I captured writing the block device:
[T15721] blkdev_write_iter:---------bdev=0xffff888117fc5080 loop2-----
[T15722] EXT4-fs error (device loop2) in ext4_reserve_inode_write:5718:
Corrupt filesystem
[T15722] EXT4-fs (loop2): Remounting filesystem read-only
[T15722] EXT4-fs error (device loop2): ext4_ext_grow_indepth:1468: inode
#16: comm rep: mark_inode_dirty error
[T15722] general protection fault, probably for non-canonical address
0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
[T15722] KASAN: null-ptr-deref in range
[0x0000000000000000-0x0000000000000007]


syzbot

unread,
Jan 24, 2024, 2:21:06 PMJan 24
to adilger...@dilger.ca, ax...@kernel.dk, bra...@kernel.org, ja...@suse.cz, linux...@vger.kernel.org, linux-...@vger.kernel.org, linux-...@vger.kernel.org, syzkall...@googlegroups.com, ty...@mit.edu, yeb...@huawei.com
syzbot suspects this issue was fixed by commit:

commit 6f861765464f43a71462d52026fbddfc858239a5
Author: Jan Kara <ja...@suse.cz>
Date: Wed Nov 1 17:43:10 2023 +0000

fs: Block writes to mounted block devices

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=102ded8be80000
start commit: 25041a4c02c7 Merge tag 'net-6.4-rc6' of git://git.kernel.o..
git tree: upstream
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11b3bc8d280000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: fs: Block writes to mounted block devices

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Theodore Ts'o

unread,
Jan 25, 2024, 7:55:46 AMJan 25
to syzbot, adilger...@dilger.ca, ax...@kernel.dk, bra...@kernel.org, ja...@suse.cz, linux...@vger.kernel.org, linux-...@vger.kernel.org, linux-...@vger.kernel.org, syzkall...@googlegroups.com, yeb...@huawei.com
On Wed, Jan 24, 2024 at 11:21:05AM -0800, syzbot wrote:
> syzbot suspects this issue was fixed by commit:
>
> commit 6f861765464f43a71462d52026fbddfc858239a5
> Author: Jan Kara <ja...@suse.cz>
> Date: Wed Nov 1 17:43:10 2023 +0000
>
> fs: Block writes to mounted block devices

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