* [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone
@ 2025-09-29 13:20 syzbot
2026-04-15 6:59 ` syzbot
2026-04-15 9:06 ` syzbot
0 siblings, 2 replies; 3+ messages in thread
From: syzbot @ 2025-09-29 13:20 UTC (permalink / raw)
To: jfs-discussion, linux-kernel, shaggy, syzkaller-bugs
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
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone
2025-09-29 13:20 [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone syzbot
@ 2026-04-15 6:59 ` syzbot
2026-04-15 9:06 ` syzbot
1 sibling, 0 replies; 3+ messages in thread
From: syzbot @ 2026-04-15 6:59 UTC (permalink / raw)
To: jfs-discussion, linux-kernel, shaggy, syzkaller-bugs
syzbot has found a reproducer for the following issue on:
HEAD commit: e6efabc0afca Add linux-next specific files for 20260414
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=161a18ce580000
kernel config: https://syzkaller.appspot.com/x/.config?x=56c2b36de3316f1b
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=107784ce580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e7099cbf73e4/disk-e6efabc0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/439c402df1b9/vmlinux-e6efabc0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fc0c0175fc76/bzImage-e6efabc0.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/01761e564f3f/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=168401ba580000)
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+0x1312/0x16c0 fs/jfs/jfs_logmgr.c:2192
Read of size 4 at addr ffff888032de1208 by task ksoftirqd/1/31
CPU: 1 UID: 0 PID: 31 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description+0x55/0x1e0 mm/kasan/report.c:378
print_report+0x58/0x70 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
lbmIODone+0x1312/0x16c0 fs/jfs/jfs_logmgr.c:2192
blk_update_request+0x57e/0xe60 block/blk-mq.c:1016
blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1178
blk_complete_reqs block/blk-mq.c:1253 [inline]
blk_done_softirq+0x10a/0x160 block/blk-mq.c:1258
handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622
run_ksoftirqd+0x52/0x180 kernel/softirq.c:1076
smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Allocated by task 6248:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x3a6/0x690 mm/slub.c:5415
kmalloc_noprof include/linux/slab.h:950 [inline]
lbmLogInit fs/jfs/jfs_logmgr.c:1819 [inline]
lmLogInit+0x3e5/0x1a00 fs/jfs/jfs_logmgr.c:1267
open_inline_log fs/jfs/jfs_logmgr.c:1173 [inline]
lmLogOpen+0x4e1/0xfa0 fs/jfs/jfs_logmgr.c:1067
jfs_mount_rw+0xee/0x670 fs/jfs/jfs_mount.c:257
jfs_fill_super+0x754/0xd80 fs/jfs/super.c:532
get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694
vfs_get_tree+0x92/0x2a0 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3758 [inline]
do_new_mount+0x341/0xd30 fs/namespace.c:3834
do_mount fs/namespace.c:4167 [inline]
__do_sys_mount fs/namespace.c:4399 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4376
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 5959:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2689 [inline]
slab_free mm/slub.c:6246 [inline]
kfree+0x1c5/0x6c0 mm/slub.c:6561
lbmLogShutdown fs/jfs/jfs_logmgr.c:1862 [inline]
lmLogShutdown+0x456/0x850 fs/jfs/jfs_logmgr.c:1681
lmLogClose+0x28a/0x520 fs/jfs/jfs_logmgr.c:1457
jfs_umount+0x2fb/0x3d0 fs/jfs/jfs_umount.c:124
jfs_put_super+0x8c/0x190 fs/jfs/super.c:194
generic_shutdown_super+0x13d/0x2d0 fs/super.c:646
kill_block_super+0x44/0x90 fs/super.c:1725
deactivate_locked_super+0xbc/0x130 fs/super.c:476
cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline]
do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff888032de1200
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 8 bytes inside of
freed 256-byte region [ffff888032de1200, ffff888032de1300)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x32de0
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88801a02cb40 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88801a02cb40 dead000000000100 dead000000000122
head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0080000000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5948, tgid 5948 (syz-executor), ts 136932809553, free_ts 131716582127
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x231/0x280 mm/page_alloc.c:1858
prep_new_page mm/page_alloc.c:1866 [inline]
get_page_from_freelist+0x27d6/0x2850 mm/page_alloc.c:3946
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5226
alloc_slab_page mm/slub.c:3278 [inline]
allocate_slab+0x77/0x660 mm/slub.c:3467
new_slab mm/slub.c:3525 [inline]
refill_objects+0x33c/0x3d0 mm/slub.c:7251
refill_sheaf mm/slub.c:2816 [inline]
__pcs_replace_empty_main+0x373/0x720 mm/slub.c:4651
alloc_from_pcs mm/slub.c:4749 [inline]
slab_alloc_node mm/slub.c:4883 [inline]
__do_kmalloc_node mm/slub.c:5294 [inline]
__kmalloc_noprof+0x530/0x7b0 mm/slub.c:5307
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
fib_create_info+0x1723/0x31f0 net/ipv4/fib_semantics.c:1400
fib_table_insert+0xc8/0x1b50 net/ipv4/fib_trie.c:1212
fib_magic+0x434/0x510 net/ipv4/fib_frontend.c:1134
fib_add_ifaddr+0x38d/0x5f0 net/ipv4/fib_frontend.c:1171
fib_netdev_event+0x382/0x490 net/ipv4/fib_frontend.c:1516
notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
call_netdevice_notifiers net/core/dev.c:2301 [inline]
__dev_notify_flags+0x1a9/0x310 net/core/dev.c:9849
netif_change_flags+0xe8/0x1a0 net/core/dev.c:9878
do_setlink+0xf82/0x4590 net/core/rtnetlink.c:3180
page last free pid 5958 tgid 5958 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1402 [inline]
__free_frozen_pages+0xf9b/0x10f0 mm/page_alloc.c:2943
__slab_free+0x252/0x2a0 mm/slub.c:5608
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4569 [inline]
slab_alloc_node mm/slub.c:4898 [inline]
kmem_cache_alloc_node_noprof+0x22a/0x6e0 mm/slub.c:4950
__alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702
alloc_skb include/linux/skbuff.h:1383 [inline]
nlmsg_new include/net/netlink.h:1055 [inline]
netlink_ack+0x146/0xa50 net/netlink/af_netlink.c:2487
netlink_rcv_skb+0x2b6/0x4b0 net/netlink/af_netlink.c:2556
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x780/0x920 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:787 [inline]
__sock_sendmsg net/socket.c:802 [inline]
__sys_sendto+0x67f/0x710 net/socket.c:2265
__do_sys_sendto net/socket.c:2272 [inline]
__se_sys_sendto net/socket.c:2268 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2268
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff888032de1100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888032de1180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888032de1200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888032de1280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888032de1300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone
2025-09-29 13:20 [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone syzbot
2026-04-15 6:59 ` syzbot
@ 2026-04-15 9:06 ` syzbot
1 sibling, 0 replies; 3+ messages in thread
From: syzbot @ 2026-04-15 9:06 UTC (permalink / raw)
To: jfs-discussion, linux-kernel, shaggy, syzkaller-bugs
syzbot has found a reproducer for the following issue on:
HEAD commit: e6efabc0afca Add linux-next specific files for 20260414
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17ee18ce580000
kernel config: https://syzkaller.appspot.com/x/.config?x=56c2b36de3316f1b
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11dc01ba580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=173bfb02580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e7099cbf73e4/disk-e6efabc0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/439c402df1b9/vmlinux-e6efabc0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fc0c0175fc76/bzImage-e6efabc0.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/81df22d6836d/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=107dfcd2580000)
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+0x1312/0x16c0 fs/jfs/jfs_logmgr.c:2192
Read of size 4 at addr ffff88802a45a608 by task ksoftirqd/1/31
CPU: 1 UID: 0 PID: 31 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description+0x55/0x1e0 mm/kasan/report.c:378
print_report+0x58/0x70 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
lbmIODone+0x1312/0x16c0 fs/jfs/jfs_logmgr.c:2192
blk_update_request+0x57e/0xe60 block/blk-mq.c:1016
blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1178
blk_complete_reqs block/blk-mq.c:1253 [inline]
blk_done_softirq+0x10a/0x160 block/blk-mq.c:1258
handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622
run_ksoftirqd+0x52/0x180 kernel/softirq.c:1076
smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Allocated by task 6106:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x3a6/0x690 mm/slub.c:5415
kmalloc_noprof include/linux/slab.h:950 [inline]
lbmLogInit fs/jfs/jfs_logmgr.c:1819 [inline]
lmLogInit+0x3e5/0x1a00 fs/jfs/jfs_logmgr.c:1267
open_inline_log fs/jfs/jfs_logmgr.c:1173 [inline]
lmLogOpen+0x4e1/0xfa0 fs/jfs/jfs_logmgr.c:1067
jfs_mount_rw+0xee/0x670 fs/jfs/jfs_mount.c:257
jfs_fill_super+0x754/0xd80 fs/jfs/super.c:532
get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694
vfs_get_tree+0x92/0x2a0 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3758 [inline]
do_new_mount+0x341/0xd30 fs/namespace.c:3834
do_mount fs/namespace.c:4167 [inline]
__do_sys_mount fs/namespace.c:4399 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4376
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 5969:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2689 [inline]
slab_free mm/slub.c:6246 [inline]
kfree+0x1c5/0x6c0 mm/slub.c:6561
lbmLogShutdown fs/jfs/jfs_logmgr.c:1862 [inline]
lmLogShutdown+0x456/0x850 fs/jfs/jfs_logmgr.c:1681
lmLogClose+0x28a/0x520 fs/jfs/jfs_logmgr.c:1457
jfs_umount+0x2fb/0x3d0 fs/jfs/jfs_umount.c:124
jfs_put_super+0x8c/0x190 fs/jfs/super.c:194
generic_shutdown_super+0x13d/0x2d0 fs/super.c:646
kill_block_super+0x44/0x90 fs/super.c:1725
deactivate_locked_super+0xbc/0x130 fs/super.c:476
cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline]
do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff88802a45a600
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 8 bytes inside of
freed 256-byte region [ffff88802a45a600, ffff88802a45a700)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a45a
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88801a02cb40 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88801a02cb40 dead000000000100 dead000000000122
head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0080000000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 155, tgid 155 (kworker/u8:6), ts 12504727555, free_ts 0
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x231/0x280 mm/page_alloc.c:1858
prep_new_page mm/page_alloc.c:1866 [inline]
get_page_from_freelist+0x27d6/0x2850 mm/page_alloc.c:3946
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5226
alloc_slab_page mm/slub.c:3278 [inline]
allocate_slab+0x77/0x660 mm/slub.c:3467
new_slab mm/slub.c:3525 [inline]
refill_objects+0x33c/0x3d0 mm/slub.c:7251
refill_sheaf mm/slub.c:2816 [inline]
__pcs_replace_empty_main+0x373/0x720 mm/slub.c:4651
alloc_from_pcs mm/slub.c:4749 [inline]
slab_alloc_node mm/slub.c:4883 [inline]
__kmalloc_cache_noprof+0x44e/0x690 mm/slub.c:5410
kmalloc_noprof include/linux/slab.h:950 [inline]
scsi_probe_and_add_lun+0x2f8/0x48e0 drivers/scsi/scsi_scan.c:1225
__scsi_scan_target+0x1f0/0xe10 drivers/scsi/scsi_scan.c:1786
scsi_scan_channel drivers/scsi/scsi_scan.c:1874 [inline]
scsi_scan_host_selected+0x3d3/0x780 drivers/scsi/scsi_scan.c:1903
do_scsi_scan_host drivers/scsi/scsi_scan.c:2036 [inline]
do_scan_async+0x124/0x6f0 drivers/scsi/scsi_scan.c:2046
async_run_entry_fn+0xa8/0x440 kernel/async.c:129
process_one_work kernel/workqueue.c:3308 [inline]
process_scheduled_works+0xb68/0x1910 kernel/workqueue.c:3399
worker_thread+0xa90/0x1040 kernel/workqueue.c:3485
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
page_owner free stack trace missing
Memory state around the buggy address:
ffff88802a45a500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802a45a580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802a45a600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802a45a680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802a45a700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
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2025-09-29 13:20 [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone syzbot
2026-04-15 6:59 ` syzbot
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