[syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

syzbot
2025-09-29T13:20:31Z

Hello,

syzbot found the following issue on:

HEAD commit: 0f3be52b8e37 Merge branch 'for-next/core' into for-kernelci
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=17509ce2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=714d45b6135c308e
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a2c3b345c3da/disk-0f3be52b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/54368457365a/vmlinux-0f3be52b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3544cf9b3f24/Image-0f3be52b.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ecf51a7ccb6b1394e90c@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in lbmIODone+0xf68/0x12e8 fs/jfs/jfs_logmgr.c:2184
Read of size 4 at addr ffff0000fa465408 by task ksoftirqd/1/23

CPU: 1 UID: 0 PID: 23 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
Call trace:
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
__dump_stack+0x30/0x40 lib/dump_stack.c:94
dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
print_address_description+0xa8/0x238 mm/kasan/report.c:378
print_report+0x68/0x84 mm/kasan/report.c:482
kasan_report+0xb0/0x110 mm/kasan/report.c:595
__asan_report_load4_noabort+0x20/0x2c mm/kasan/report_generic.c:380
lbmIODone+0xf68/0x12e8 fs/jfs/jfs_logmgr.c:2184
bio_endio+0x858/0x894 block/bio.c:1651
blk_update_request+0x474/0xba8 block/blk-mq.c:989
blk_mq_end_request+0x54/0x88 block/blk-mq.c:1151
lo_complete_rq+0x124/0x274 drivers/block/loop.c:314
blk_complete_reqs block/blk-mq.c:1226 [inline]
blk_done_softirq+0x11c/0x168 block/blk-mq.c:1231
handle_softirqs+0x328/0xc88 kernel/softirq.c:579
run_ksoftirqd+0x70/0xc0 kernel/softirq.c:968
smpboot_thread_fn+0x4d8/0x9cc kernel/smpboot.c:160
kthread+0x5fc/0x75c kernel/kthread.c:463
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844

Allocated by task 6893:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x40/0x78 mm/kasan/common.c:68
kasan_save_alloc_info+0x44/0x54 mm/kasan/generic.c:562
poison_kmalloc_redzone mm/kasan/common.c:388 [inline]
__kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:405
kasan_kmalloc include/linux/kasan.h:260 [inline]
__kmalloc_cache_noprof+0x2a4/0x3fc mm/slub.c:4407
kmalloc_noprof include/linux/slab.h:905 [inline]
lbmLogInit fs/jfs/jfs_logmgr.c:1822 [inline]
lmLogInit+0x690/0x1a9c fs/jfs/jfs_logmgr.c:1270
open_inline_log fs/jfs/jfs_logmgr.c:1175 [inline]
lmLogOpen+0x41c/0xd5c fs/jfs/jfs_logmgr.c:1069
jfs_mount_rw+0xe4/0x548 fs/jfs/jfs_mount.c:257
jfs_fill_super+0x5d4/0xb6c fs/jfs/super.c:532
get_tree_bdev_flags+0x360/0x414 fs/super.c:1692
get_tree_bdev+0x2c/0x3c fs/super.c:1715
jfs_get_tree+0x28/0x38 fs/jfs/super.c:635
vfs_get_tree+0x90/0x28c fs/super.c:1815
do_new_mount+0x278/0x7f4 fs/namespace.c:3808
path_mount+0x5b4/0xde0 fs/namespace.c:4123
do_mount fs/namespace.c:4136 [inline]
__do_sys_mount fs/namespace.c:4347 [inline]
__se_sys_mount fs/namespace.c:4324 [inline]
__arm64_sys_mount+0x3e8/0x468 fs/namespace.c:4324
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

Freed by task 6536:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x40/0x78 mm/kasan/common.c:68
kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:576
poison_slab_object mm/kasan/common.c:243 [inline]
__kasan_slab_free+0x74/0x98 mm/kasan/common.c:275
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2422 [inline]
slab_free mm/slub.c:4695 [inline]
kfree+0x17c/0x474 mm/slub.c:4894
lbmLogShutdown fs/jfs/jfs_logmgr.c:1865 [inline]
lmLogShutdown+0x36c/0x700 fs/jfs/jfs_logmgr.c:1684
lmLogClose+0x244/0x4c4 fs/jfs/jfs_logmgr.c:1460
jfs_umount+0x26c/0x350 fs/jfs/jfs_umount.c:114
jfs_put_super+0x90/0x188 fs/jfs/super.c:194
generic_shutdown_super+0x12c/0x2b8 fs/super.c:643
kill_block_super+0x44/0x90 fs/super.c:1766
deactivate_locked_super+0xc4/0x12c fs/super.c:474
deactivate_super+0xe0/0x100 fs/super.c:507
cleanup_mnt+0x31c/0x3ac fs/namespace.c:1375
__cleanup_mnt+0x20/0x30 fs/namespace.c:1382
task_work_run+0x1dc/0x260 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xfc/0x168 kernel/entry/common.c:43
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
arm64_exit_to_user_mode arch/arm64/kernel/entry-common.c:103 [inline]
el0_svc+0x170/0x254 arch/arm64/kernel/entry-common.c:745
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

The buggy address belongs to the object at ffff0000fa465400
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 8 bytes inside of
freed 192-byte region [ffff0000fa465400, ffff0000fa4654c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x13a465
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 05ffc00000000000 ffff0000c00013c0 fffffdffc3070180 0000000000000004
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff0000fa465300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff0000fa465380: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
>ffff0000fa465400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff0000fa465480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff0000fa465500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

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