[syzbot] divide error in do_journal_end (2)

[syzbot <syzbot+0ba9909df31c6a36974d@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    88b06399 Merge tag 'for-5.13-rc1-part2-tag' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13516d93d00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=807beec6b4d66bf1
dashboard link: https://syzkaller.appspot.com/bug?extid=0ba9909df31c6a36974d
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=123b4d63d00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16813c65d00000

Bisection is inconclusive: the issue happens on the oldest tested release.

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=11e35795d00000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=13e35795d00000
console output: https://syzkaller.appspot.com/x/log.txt?x=15e35795d00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0ba9909df31c6a36974d@syzkaller.appspotmail.com

REISERFS (device loop0): journal params: device loop0, size 8192, journal first block 10, max trans len 1024, max batch 900, max commit age 30, max trans age 30
REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop0): Using r5 hash to sort names
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
divide error: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 8393 Comm: syz-executor119 Not tainted 5.13.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:do_journal_end+0x24aa/0x4950 fs/reiserfs/journal.c:4188
Code: c1 45 84 ca 0f 85 67 18 00 00 83 e2 07 40 38 d6 41 0f 9e c1 40 84 f6 0f 95 c2 41 84 d1 0f 85 4e 18 00 00 41 8b 7c 24 14 31 d2 <48> f7 f7 49 8d 7d 18 48 8d 34 0a 48 89 f8 48 c1 e8 03 80 3c 18 00
RSP: 0018:ffffc9000187faa0 EFLAGS: 00010246
RAX: 0000000000000005 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900016c1048 R08: 0000000000001000 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880349b1000
R13: ffff8880285b9000 R14: ffff88801248d4c0 R15: ffff888019b28000
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055cf21e91b70 CR3: 0000000013782000 CR4: 0000000000350ef0
Call Trace:
 reiserfs_sync_fs+0xf8/0x120 fs/reiserfs/super.c:78
 __sync_filesystem fs/sync.c:39 [inline]
 sync_filesystem fs/sync.c:67 [inline]
 sync_filesystem+0x1b5/0x260 fs/sync.c:48
 generic_shutdown_super+0x70/0x370 fs/super.c:448
 kill_block_super+0x97/0xf0 fs/super.c:1395
 deactivate_locked_super+0x94/0x160 fs/super.c:335
 deactivate_super+0xad/0xd0 fs/super.c:366
 cleanup_mnt+0x3a2/0x540 fs/namespace.c:1136
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0xbfc/0x2a60 kernel/exit.c:826
 do_group_exit+0x125/0x310 kernel/exit.c:923
 __do_sys_exit_group kernel/exit.c:934 [inline]
 __se_sys_exit_group kernel/exit.c:932 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:932
 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4438c9
Code: Unable to access opcode bytes at RIP 0x44389f.
RSP: 002b:00007ffe1e8a33f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00000000004b52f0 RCX: 00000000004438c9
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000001
RBP: 0000000000000001 R08: ffffffffffffffc4 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004b52f0
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
Modules linked in:
---[ end trace 918df66ba4209fe1 ]---
RIP: 0010:do_journal_end+0x24aa/0x4950 fs/reiserfs/journal.c:4188
Code: c1 45 84 ca 0f 85 67 18 00 00 83 e2 07 40 38 d6 41 0f 9e c1 40 84 f6 0f 95 c2 41 84 d1 0f 85 4e 18 00 00 41 8b 7c 24 14 31 d2 <48> f7 f7 49 8d 7d 18 48 8d 34 0a 48 89 f8 48 c1 e8 03 80 3c 18 00
RSP: 0018:ffffc9000187faa0 EFLAGS: 00010246
RAX: 0000000000000005 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900016c1048 R08: 0000000000001000 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880349b1000
R13: ffff8880285b9000 R14: ffff88801248d4c0 R15: ffff888019b28000
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055cf21e91b70 CR3: 00000000133f2000 CR4: 0000000000350ef0


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