From: syzbot <syzbot+1afe7ef2d0062e19eeb3@syzkaller.appspotmail.com>
To: jchuang26@m.fudan.edu.cn, linux-kernel@vger.kernel.org,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [jfs?] UBSAN: array-index-out-of-bounds in dbFindLeaf (2)
Date: Wed, 16 Sep 2026 18:49:02 -0700 [thread overview]
Message-ID: <6aab470e.b398a7c9.1f86be.0007.GAE@google.com> (raw)
In-Reply-To: <6aab422e.d91e0f37.3a5804.cd4fSMTPIN_ADDED_BROKEN@gmr-mx.google.com>
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in lbmIODone
==================================================================
BUG: KASAN: slab-use-after-free in lbmIODone+0x130e/0x16b0 fs/jfs/jfs_logmgr.c:2192
Read of size 4 at addr ffff88802babf608 by task ktimers/0/16
CPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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+0x130e/0x16b0 fs/jfs/jfs_logmgr.c:2192
blk_update_request+0x57b/0xe50 block/blk-mq.c:1016
blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1147
blk_complete_reqs block/blk-mq.c:1222 [inline]
blk_done_softirq+0x10a/0x160 block/blk-mq.c:1227
handle_softirqs+0x1da/0x6d0 kernel/softirq.c:645
__do_softirq kernel/softirq.c:679 [inline]
run_ktimerd+0x6a/0x100 kernel/softirq.c:1174
smpboot_thread_fn+0x565/0xa70 kernel/smpboot.c:160
kthread+0x38b/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 6752:
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+0x3d5/0x680 mm/slub.c:5563
_kmalloc_noprof include/linux/slab.h:991 [inline]
lbmLogInit fs/jfs/jfs_logmgr.c:1819 [inline]
lmLogInit+0x3e5/0x1a20 fs/jfs/jfs_logmgr.c:1267
open_inline_log fs/jfs/jfs_logmgr.c:1173 [inline]
lmLogOpen+0x4e3/0xf90 fs/jfs/jfs_logmgr.c:1067
jfs_mount_rw+0xf3/0x670 fs/jfs/jfs_mount.c:257
jfs_fill_super+0x769/0xda0 fs/jfs/super.c:533
get_tree_bdev_flags+0x430/0x4f0 fs/super.c:1873
vfs_get_tree+0x92/0x2a0 fs/super.c:1933
fc_mount fs/namespace.c:1198 [inline]
do_new_mount_fc fs/namespace.c:3772 [inline]
do_new_mount+0x319/0xdc0 fs/namespace.c:3848
do_mount fs/namespace.c:4181 [inline]
__do_sys_mount fs/namespace.c:4397 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4374
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x155/0x510 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 6475:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x40/0x50 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:2748 [inline]
slab_free mm/slub.c:6508 [inline]
kfree+0x1c5/0x6d0 mm/slub.c:6801
lbmLogShutdown fs/jfs/jfs_logmgr.c:1862 [inline]
lmLogShutdown+0x456/0x850 fs/jfs/jfs_logmgr.c:1681
lmLogClose+0x28c/0x530 fs/jfs/jfs_logmgr.c:1457
jfs_umount+0x2da/0x3b0 fs/jfs/jfs_umount.c:124
jfs_put_super+0x8c/0x190 fs/jfs/super.c:194
generic_shutdown_super+0x13d/0x2d0 fs/super.c:755
kill_block_super+0x44/0xa0 fs/super.c:1904
deactivate_locked_super+0xbc/0x110 fs/super.c:589
cleanup_mnt+0x3d3/0x460 fs/namespace.c:1317
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:70 [inline]
exit_to_user_mode_loop+0x14e/0x570 kernel/entry/common.c:101
__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:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline]
do_syscall_64+0x317/0x510 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff88802babf600
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 8 bytes inside of
freed 256-byte region [ffff88802babf600, ffff88802babf700)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88802babfc00 pfn:0x2babe
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000240(workingset|head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000240 ffff88813febeb40 ffffea0000bf8690 ffff88813febd988
raw: ffff88802babfc00 000000000010000e 00000000f5000000 0000000000000000
head: 0080000000000240 ffff88813febeb40 ffffea0000bf8690 ffff88813febd988
head: ffff88802babfc00 000000000010000e 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 6752, tgid 6751 (syz.0.56), ts 258143057879
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871
prep_new_page mm/page_alloc.c:1879 [inline]
get_page_from_freelist+0x2591/0x2600 mm/page_alloc.c:3943
__alloc_frozen_pages_noprof+0x230/0x5c0 mm/page_alloc.c:5436
alloc_slab_page mm/slub.c:3347 [inline]
allocate_slab+0x7d/0x620 mm/slub.c:3462
new_slab mm/slub.c:3513 [inline]
refill_objects+0x2d8/0x350 mm/slub.c:7417
refill_sheaf mm/slub.c:2885 [inline]
__pcs_replace_empty_main+0x339/0x690 mm/slub.c:4774
alloc_from_pcs mm/slub.c:4850 [inline]
slab_alloc_node mm/slub.c:4984 [inline]
__kmalloc_cache_noprof+0x46f/0x680 mm/slub.c:5559
_kmalloc_noprof include/linux/slab.h:991 [inline]
lbmLogInit fs/jfs/jfs_logmgr.c:1819 [inline]
lmLogInit+0x3e5/0x1a20 fs/jfs/jfs_logmgr.c:1267
open_inline_log fs/jfs/jfs_logmgr.c:1173 [inline]
lmLogOpen+0x4e3/0xf90 fs/jfs/jfs_logmgr.c:1067
jfs_mount_rw+0xf3/0x670 fs/jfs/jfs_mount.c:257
jfs_fill_super+0x769/0xda0 fs/jfs/super.c:533
get_tree_bdev_flags+0x430/0x4f0 fs/super.c:1873
vfs_get_tree+0x92/0x2a0 fs/super.c:1933
fc_mount fs/namespace.c:1198 [inline]
do_new_mount_fc fs/namespace.c:3772 [inline]
do_new_mount+0x319/0xdc0 fs/namespace.c:3848
do_mount fs/namespace.c:4181 [inline]
__do_sys_mount fs/namespace.c:4397 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4374
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x155/0x510 arch/x86/entry/syscall_64.c:84
page last free pid 6132 tgid 6132 ts 257131051219 stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1418 [inline]
__free_frozen_pages+0xf3d/0x1000 mm/page_alloc.c:2962
__slab_free+0x250/0x2a0 mm/slub.c:5823
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:4683 [inline]
slab_alloc_node mm/slub.c:4996 [inline]
__do_kmalloc_node mm/slub.c:5413 [inline]
__kmalloc_noprof+0x3b9/0x790 mm/slub.c:5439
_kmalloc_noprof include/linux/slab.h:995 [inline]
tomoyo_realpath_from_path+0xef/0x640 security/tomoyo/realpath.c:251
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_path_number_perm+0x246/0x5f0 security/tomoyo/file.c:728
security_file_ioctl+0xc3/0x2a0 security/security.c:2512
__do_sys_ioctl fs/ioctl.c:591 [inline]
__se_sys_ioctl+0x47/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x155/0x510 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff88802babf500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802babf580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802babf600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802babf680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802babf700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
Tested on:
commit: 238650ef Merge tag 'powerpc-7.3-4' of git://git.kernel..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=150b93f9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=a8915f6d5e9da1d8
dashboard link: https://syzkaller.appspot.com/bug?extid=1afe7ef2d0062e19eeb3
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=115458c9580000
next parent reply other threads:[~2026-09-17 1:49 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <6aab422e.d91e0f37.3a5804.cd4fSMTPIN_ADDED_BROKEN@gmr-mx.google.com>
2026-09-17 1:49 ` syzbot [this message]
[not found] <6aa8a1b1.9cc10357.125c5.d000SMTPIN_ADDED_BROKEN@gmr-mx.google.com>
2026-09-15 2:03 ` syzbot
[not found] <6aa7e616.0d1f51e9.2e6de3.473fSMTPIN_ADDED_BROKEN@gmr-mx.google.com>
2026-09-14 15:46 ` syzbot
[not found] <177644278876.3785156.11786245630332071250@talencesecurity.com>
2026-04-17 17:17 ` syzbot
[not found] <20260417101153.2489040-1-tristmd@gmail.com>
2026-04-17 10:27 ` syzbot
2026-01-08 13:00 syzbot
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