[syzbot] [jfs?] KASAN: user-memory-access Write in __destroy_inode

[syzbot] [jfs?] KASAN: user-memory-access Write in __destroy_inode

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    fa31fc82fb77 Merge tag 'pm-6.4-rc1-2' of git://git.kernel...
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=176f146c280000
kernel config:  https://syzkaller.appspot.com/x/.config?x=73a06f6ef2d5b492
dashboard link: https://syzkaller.appspot.com/bug?extid=dcc068159182a4c31ca3
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=13a40690280000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=156b965c280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/47047382df87/disk-fa31fc82.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1fd540f5f80a/vmlinux-fa31fc82.xz
kernel image: https://storage.googleapis.com/syzbot-assets/21da1f9e2c23/bzImage-fa31fc82.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/058ce906b620/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dcc068159182a4c31ca3@syzkaller.appspotmail.com

ERROR: (device loop0): jfs_readdir: JFS:Dtree error: ino = 2, bn=0, index = 6
ERROR: (device loop0): jfs_readdir: JFS:Dtree error: ino = 2, bn=0, index = 7
==================================================================
BUG: KASAN: user-memory-access in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: user-memory-access in atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:176 [inline]
BUG: KASAN: user-memory-access in __refcount_sub_and_test include/linux/refcount.h:272 [inline]
BUG: KASAN: user-memory-access in __refcount_dec_and_test include/linux/refcount.h:315 [inline]
BUG: KASAN: user-memory-access in refcount_dec_and_test include/linux/refcount.h:333 [inline]
BUG: KASAN: user-memory-access in posix_acl_release include/linux/posix_acl.h:57 [inline]
BUG: KASAN: user-memory-access in __destroy_inode+0x426/0x5e0 fs/inode.c:297
Write of size 4 at addr 0000000b00000000 by task syz-executor374/4998

CPU: 0 PID: 4998 Comm: syz-executor374 Not tainted 6.3.0-syzkaller-12999-gfa31fc82fb77 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 print_report+0xe6/0x540 mm/kasan/report.c:465
 kasan_report+0x176/0x1b0 mm/kasan/report.c:572
 kasan_check_range+0x283/0x290 mm/kasan/generic.c:187
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:176 [inline]
 __refcount_sub_and_test include/linux/refcount.h:272 [inline]
 __refcount_dec_and_test include/linux/refcount.h:315 [inline]
 refcount_dec_and_test include/linux/refcount.h:333 [inline]
 posix_acl_release include/linux/posix_acl.h:57 [inline]
 __destroy_inode+0x426/0x5e0 fs/inode.c:297
 destroy_inode fs/inode.c:308 [inline]
 evict+0x51b/0x620 fs/inode.c:680
 dispose_list fs/inode.c:698 [inline]
 evict_inodes+0x5f8/0x690 fs/inode.c:748
 generic_shutdown_super+0x98/0x340 fs/super.c:479
 kill_block_super+0x84/0xf0 fs/super.c:1407
 deactivate_locked_super+0xa4/0x110 fs/super.c:331
 cleanup_mnt+0x426/0x4c0 fs/namespace.c:1177
 task_work_run+0x24a/0x300 kernel/task_work.c:179
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x68f/0x2290 kernel/exit.c:871
 do_group_exit+0x206/0x2c0 kernel/exit.c:1021
 __do_sys_exit_group kernel/exit.c:1032 [inline]
 __se_sys_exit_group kernel/exit.c:1030 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1030
 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: 0033:0x7f696702ea49
Code: Unable to access opcode bytes at 0x7f696702ea1f.
RSP: 002b:00007ffcc25baa18 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f69670a9330 RCX: 00007f696702ea49
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000001
RBP: 0000000000000001 R08: ffffffffffffffc0 R09: 00007f69670a3e40
R10: 00007f69670a3e40 R11: 0000000000000246 R12: 00007f69670a9330
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
 </TASK>
==================================================================


---
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Forwarded: #syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git cec1e6e5d1ab33403b809f79cd20d6aff124ccfe

[syzbot]

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***

Subject: #syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git cec1e6e5d1ab33403b809f79cd20d6aff124ccfe
Author: dmantipov@yandex.ru

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git cec1e6e5d1ab33403b809f79cd20d6aff124ccfe

Re: [syzbot] [jfs?] KASAN: user-memory-access Write in __destroy_inode

[syzbot]

syzbot suspects this issue was fixed by commit:

commit dca3aa666fbd71118905d88bb1c353881002b647
Author: Mateusz Guzik <mjguzik@gmail.com>
Date:   Sun Nov 9 12:19:31 2025 +0000

    fs: move inode fields used during fast path lookup closer together

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1480019a580000
start commit:   6146a0f1dfae Linux 6.18-rc4
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=e46b8a1c645465a9
dashboard link: https://syzkaller.appspot.com/bug?extid=dcc068159182a4c31ca3
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15ef4532580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=179c1e14580000

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

#syz fix: fs: move inode fields used during fast path lookup closer together

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

Re: [syzbot] [jfs?] KASAN: user-memory-access Write in __destroy_inode

[Mateusz Guzik]

On Wed, Jan 7, 2026 at 3:57 PM syzbot
<syzbot+dcc068159182a4c31ca3@syzkaller.appspotmail.com> wrote:
>
> syzbot suspects this issue was fixed by commit:
>
> commit dca3aa666fbd71118905d88bb1c353881002b647
> Author: Mateusz Guzik <mjguzik@gmail.com>
> Date:   Sun Nov 9 12:19:31 2025 +0000
>
>     fs: move inode fields used during fast path lookup closer together
>

I don't know what the bug is, at best this patch has an unintended
side-effect of neutering the reproducer.

> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1480019a580000
> start commit:   6146a0f1dfae Linux 6.18-rc4
> git tree:       upstream
> kernel config:  https://syzkaller.appspot.com/x/.config?x=e46b8a1c645465a9
> dashboard link: https://syzkaller.appspot.com/bug?extid=dcc068159182a4c31ca3
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15ef4532580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=179c1e14580000
>
> If the result looks correct, please mark the issue as fixed by replying with:
>
> #syz fix: fs: move inode fields used during fast path lookup closer together
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection