[v5.15] divide error in do_journal_end

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d54cfc420586 Linux 5.15.120
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1586d728a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=c67dae6b27f0d6cd
dashboard link: https://syzkaller.appspot.com/bug?extid=8b4def6a27716cebedb3
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=166e1190a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=168b1cbca80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4aa2cbf1e81c/disk-d54cfc42.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2ebee78b098c/vmlinux-d54cfc42.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4e17f9ac4b6a/bzImage-d54cfc42.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/ef27ba77cb29/mount_0.gz
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/e90351a6f0d4/mount_4.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8b4def...@syzkaller.appspotmail.com

divide error: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 21 Comm: kworker/1:0 Not tainted 5.15.120-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023
Workqueue: events_long flush_old_commits
RIP: 0010:do_journal_end+0x12f1/0x4650 fs/reiserfs/journal.c:4087
Code: 04 30 84 c0 0f 85 74 2d 00 00 4f 8d 7c 2f 01 48 89 e8 48 c1 e8 03 42 0f b6 04 30 84 c0 0f 85 7a 2d 00 00 8b 0b 4c 89 f8 31 d2 <48> f7 f1 48 89 d3 4c 01 e3 48 8b 84 24 c8 00 00 00 42 80 3c 30 00
RSP: 0018:ffffc90000db79b0 EFLAGS: 00010246
RAX: 0000000000000003 RBX: ffff888070a69014 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88807292a000
RBP: ffff888070a69017 R08: dffffc0000000000 R09: ffff88807292a000
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: 0000000000000002 R14: dffffc0000000000 R15: 0000000000000003
FS: 0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2483add000 CR3: 00000000757f9000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
reiserfs_sync_fs fs/reiserfs/super.c:78 [inline]
flush_old_commits+0x20d/0x2e0 fs/reiserfs/super.c:111
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2307
worker_thread+0xaca/0x1280 kernel/workqueue.c:2454
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
</TASK>
Modules linked in:
---[ end trace 6195c43b7cf57da6 ]---
RIP: 0010:do_journal_end+0x12f1/0x4650 fs/reiserfs/journal.c:4087
Code: 04 30 84 c0 0f 85 74 2d 00 00 4f 8d 7c 2f 01 48 89 e8 48 c1 e8 03 42 0f b6 04 30 84 c0 0f 85 7a 2d 00 00 8b 0b 4c 89 f8 31 d2 <48> f7 f1 48 89 d3 4c 01 e3 48 8b 84 24 c8 00 00 00 42 80 3c 30 00
RSP: 0018:ffffc90000db79b0 EFLAGS: 00010246
RAX: 0000000000000003 RBX: ffff888070a69014 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88807292a000
RBP: ffff888070a69017 R08: dffffc0000000000 R09: ffff88807292a000
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: 0000000000000002 R14: dffffc0000000000 R15: 0000000000000003
FS: 0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ebeec94008 CR3: 0000000021d4d000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 04 30 add $0x30,%al
2: 84 c0 test %al,%al
4: 0f 85 74 2d 00 00 jne 0x2d7e
a: 4f 8d 7c 2f 01 lea 0x1(%r15,%r13,1),%r15
f: 48 89 e8 mov %rbp,%rax
12: 48 c1 e8 03 shr $0x3,%rax
16: 42 0f b6 04 30 movzbl (%rax,%r14,1),%eax
1b: 84 c0 test %al,%al
1d: 0f 85 7a 2d 00 00 jne 0x2d9d
23: 8b 0b mov (%rbx),%ecx
25: 4c 89 f8 mov %r15,%rax
28: 31 d2 xor %edx,%edx
* 2a: 48 f7 f1 div %rcx <-- trapping instruction
2d: 48 89 d3 mov %rdx,%rbx
30: 4c 01 e3 add %r12,%rbx
33: 48 8b 84 24 c8 00 00 mov 0xc8(%rsp),%rax
3a: 00
3b: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1)


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