kernel BUG in ext4_writepages

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 44b8b2ac1d96 Merge 5.15.73 into android13-5.15-lts
git tree: android13-5.15-lts
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1755f99a880000
kernel config: https://syzkaller.appspot.com/x/.config?x=c7f461eef7aac48
dashboard link: https://syzkaller.appspot.com/bug?extid=a158d886ca08a3fecca4
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=122970ba880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=128c48d2880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/eae95419fc66/disk-44b8b2ac.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/40ad978c1f0f/vmlinux-44b8b2ac.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/76507722aadc/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a158d8...@syzkaller.appspotmail.com

EXT4-fs (loop0): mounted filesystem without journal. Opts: ,errors=continue. Quota mode: none.
------------[ cut here ]------------
kernel BUG at fs/ext4/inode.c:2731!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 424 Comm: syz-executor258 Not tainted 5.15.73-syzkaller-04348-g44b8b2ac1d96 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
RIP: 0010:ext4_writepages+0x3b91/0x3bb0 fs/ext4/inode.c:2730
Code: c6 31 ff e8 41 95 81 ff 84 db 75 2c e8 28 92 81 ff 48 bb 00 00 00 00 00 fc ff df 4c 8b 7c 24 48 e9 d3 c9 ff ff e8 0f 92 81 ff <0f> 0b e8 08 92 81 ff e8 1f 82 10 ff eb a0 e8 fc 91 81 ff e8 13 82
RSP: 0018:ffffc9000030f260 EFLAGS: 00010293
RAX: ffffffff81efff81 RBX: 0000008000000000 RCX: ffff888107184f00
RDX: 0000000000000000 RSI: 0000008000000000 RDI: 0000000000000000
RBP: ffffc9000030f650 R08: ffffffff81efcb8f R09: ffffed10212ef5e3
R10: ffffed10212ef5e3 R11: 1ffff110212ef5e2 R12: ffffc9000030f880
R13: 0000000000000001 R14: 000000c410000000 R15: ffffc9000030f520
FS: 00005555569f4300(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004571f0 CR3: 000000011f6f5000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
do_writepages+0x442/0x6c0 mm/page-writeback.c:2364
filemap_fdatawrite_wbc+0x245/0x2a0 mm/filemap.c:400
__filemap_fdatawrite_range mm/filemap.c:433 [inline]
file_write_and_wait_range+0x1e5/0x2e0 mm/filemap.c:810
ext4_sync_file+0x19e/0xa00 fs/ext4/fsync.c:151
vfs_fsync_range+0x17b/0x190 fs/sync.c:188
generic_write_sync include/linux/fs.h:2949 [inline]
ext4_buffered_write_iter+0x584/0x630 fs/ext4/file.c:279
ext4_file_write_iter+0x456/0x1dc0
call_write_iter include/linux/fs.h:2129 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0xc8d/0x1050 fs/read_write.c:594
ksys_write+0x198/0x2c0 fs/read_write.c:647
__do_sys_write fs/read_write.c:659 [inline]
__se_sys_write fs/read_write.c:656 [inline]
__x64_sys_write+0x7b/0x90 fs/read_write.c:656
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f438b013ef9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd350d4f48 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 00007f438b013ef9
RDX: 0000000000000088 RSI: 0000000020000440 RDI: 0000000000000006
RBP: 00007f438afd36f0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f438afd3780
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
Modules linked in:
---[ end trace 06d0076835369f22 ]---
RIP: 0010:ext4_writepages+0x3b91/0x3bb0 fs/ext4/inode.c:2730
Code: c6 31 ff e8 41 95 81 ff 84 db 75 2c e8 28 92 81 ff 48 bb 00 00 00 00 00 fc ff df 4c 8b 7c 24 48 e9 d3 c9 ff ff e8 0f 92 81 ff <0f> 0b e8 08 92 81 ff e8 1f 82 10 ff eb a0 e8 fc 91 81 ff e8 13 82
RSP: 0018:ffffc9000030f260 EFLAGS: 00010293
RAX: ffffffff81efff81 RBX: 0000008000000000 RCX: ffff888107184f00
RDX: 0000000000000000 RSI: 0000008000000000 RDI: 0000000000000000
RBP: ffffc9000030f650 R08: ffffffff81efcb8f R09: ffffed10212ef5e3
R10: ffffed10212ef5e3 R11: 1ffff110212ef5e2 R12: ffffc9000030f880
R13: 0000000000000001 R14: 000000c410000000 R15: ffffc9000030f520
FS: 00005555569f4300(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004571f0 CR3: 000000011f6f5000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[Jun Nie]

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

[Jun Nie]

It is likely related to previous ext4_write_inline_data_end bug. Test a possible fix patch for Bin, the author of previous fix patch, but does not help. Bin does not have idea so far:

issue should be caused by the concurrency of inline data conversion and buffer write.

https://lore.kernel.org/lkml/63903521...@huawei.com/