==================================================================
BUG: KASAN: use-after-free in kernfs_root fs/kernfs/kernfs-internal.h:66 [inline]
BUG: KASAN: use-after-free in kernfs_find_and_get_ns+0x3c/0x110 fs/kernfs/dir.c:903
Read of size 8 at addr ffff8881303e4580 by task kworker/0:6/1427
CPU: 0 PID: 1427 Comm: kworker/0:6 Not tainted 6.1.129-syzkaller-00051-gc1fd50266bd6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events flush_stashed_error_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x151/0x1b7 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:316 [inline]
print_report+0x158/0x4e0 mm/kasan/report.c:427
kasan_report+0x13c/0x170 mm/kasan/report.c:531
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:351
kernfs_root fs/kernfs/kernfs-internal.h:66 [inline]
kernfs_find_and_get_ns+0x3c/0x110 fs/kernfs/dir.c:903
kernfs_find_and_get include/linux/kernfs.h:614 [inline]
sysfs_notify+0x73/0xd0 fs/sysfs/file.c:190
ext4_notify_error_sysfs+0x25/0x30 fs/ext4/sysfs.c:518
flush_stashed_error_work+0x2fe/0x320 fs/ext4/super.c:-1
process_one_work+0x73d/0xcb0 kernel/workqueue.c:2299
worker_thread+0xa60/0x1260 kernel/workqueue.c:2446
kthread+0x26d/0x300 kernel/kthread.c:386
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Allocated by task 1566:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:333
kasan_slab_alloc include/linux/kasan.h:202 [inline]
slab_post_alloc_hook+0x53/0x2c0 mm/slab.h:768
slab_alloc_node mm/slub.c:3421 [inline]
slab_alloc mm/slub.c:3431 [inline]
__kmem_cache_alloc_lru mm/slub.c:3438 [inline]
kmem_cache_alloc+0x175/0x320 mm/slub.c:3447
kmem_cache_zalloc include/linux/slab.h:689 [inline]
__kernfs_new_node+0xdb/0x700 fs/kernfs/dir.c:614
kernfs_new_node+0x130/0x230 fs/kernfs/dir.c:690
kernfs_create_dir_ns+0x44/0x130 fs/kernfs/dir.c:1046
sysfs_create_dir_ns+0x185/0x390 fs/sysfs/dir.c:59
create_dir lib/kobject.c:63 [inline]
kobject_add_internal+0x635/0xbf0 lib/kobject.c:231
kobject_add_varg lib/kobject.c:366 [inline]
kobject_init_and_add+0x120/0x190 lib/kobject.c:449
ext4_register_sysfs+0xbf/0x2c0 fs/ext4/sysfs.c:531
__ext4_fill_super fs/ext4/super.c:5486 [inline]
ext4_fill_super+0x796e/0x8450 fs/ext4/super.c:5641
get_tree_bdev+0x440/0x680 fs/super.c:1368
ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5671
vfs_get_tree+0x88/0x290 fs/super.c:1575
do_new_mount+0x2ba/0xb30 fs/namespace.c:3056
path_mount+0x671/0x1070 fs/namespace.c:3386
do_mount fs/namespace.c:3399 [inline]
__do_sys_mount fs/namespace.c:3607 [inline]
__se_sys_mount+0x2c4/0x3b0 fs/namespace.c:3584
__x64_sys_mount+0xbf/0xd0 fs/namespace.c:3584
x64_sys_call+0x49d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:166
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Freed by task 631:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516
____kasan_slab_free+0x131/0x180 mm/kasan/common.c:241
__kasan_slab_free+0x11/0x20 mm/kasan/common.c:249
kasan_slab_free include/linux/kasan.h:178 [inline]
slab_free_hook mm/slub.c:1745 [inline]
slab_free_freelist_hook mm/slub.c:1771 [inline]
slab_free mm/slub.c:3686 [inline]
kmem_cache_free+0x291/0x560 mm/slub.c:3711
kernfs_put+0x392/0x520 fs/kernfs/dir.c:568
sysfs_put include/linux/sysfs.h:657 [inline]
__kobject_del+0x10f/0x300 lib/kobject.c:597
kobject_del+0x45/0x60 lib/kobject.c:619
ext4_unregister_sysfs+0x91/0xa0 fs/ext4/sysfs.c:565
ext4_put_super+0x7d/0xd60 fs/ext4/super.c:1216
generic_shutdown_super+0x14f/0x370 fs/super.c:503
kill_block_super+0x7e/0xe0 fs/super.c:1472
deactivate_locked_super+0xad/0x110 fs/super.c:334
deactivate_super+0xbe/0xf0 fs/super.c:365
cleanup_mnt+0x485/0x510 fs/namespace.c:1186
__cleanup_mnt+0x19/0x20 fs/namespace.c:1193
task_work_run+0x24d/0x2e0 kernel/task_work.c:203
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0x94/0xa0 kernel/entry/common.c:177
exit_to_user_mode_prepare+0x5a/0xa0 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x26/0x130 kernel/entry/common.c:303
do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
The buggy address belongs to the object at ffff8881303e4578
which belongs to the cache kernfs_node_cache of size 136
The buggy address is located 8 bytes inside of
136-byte region [ffff8881303e4578, ffff8881303e4600)
The buggy address belongs to the physical page:
page:ffffea0004c0f900 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1303e4
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 ffffea0004c0a500 dead000000000002 ffff8881002ab500
raw: 0000000000000000 0000000000140014 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 294, tgid 294 (syz-executor), ts 23882127584, free_ts 0
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x213/0x220 mm/page_alloc.c:2637
prep_new_page+0x1b/0x110 mm/page_alloc.c:2644
get_page_from_freelist+0x3a98/0x3b10 mm/page_alloc.c:4539
__alloc_pages+0x234/0x610 mm/page_alloc.c:5837
alloc_slab_page+0x6c/0xf0 include/linux/gfp.h:-1
allocate_slab mm/slub.c:1962 [inline]
new_slab+0x90/0x3e0 mm/slub.c:2015
___slab_alloc+0x6f9/0xb80 mm/slub.c:3203
__slab_alloc+0x5d/0xa0 mm/slub.c:3302
slab_alloc_node mm/slub.c:3387 [inline]
slab_alloc mm/slub.c:3431 [inline]
__kmem_cache_alloc_lru mm/slub.c:3438 [inline]
kmem_cache_alloc+0x1be/0x320 mm/slub.c:3447
kmem_cache_zalloc include/linux/slab.h:689 [inline]
__kernfs_new_node+0xdb/0x700 fs/kernfs/dir.c:614
kernfs_new_node+0x130/0x230 fs/kernfs/dir.c:690
kernfs_create_dir_ns+0x44/0x130 fs/kernfs/dir.c:1046
internal_create_group+0x2a1/0xed0 fs/sysfs/group.c:136
sysfs_create_group+0x1f/0x30 fs/sysfs/group.c:174
dpm_sysfs_add+0x72/0x2b0 drivers/base/power/sysfs.c:702
device_add+0x6df/0xf10 drivers/base/core.c:3654
page_owner free stack trace missing
Memory state around the buggy address:
ffff8881303e4480: fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb
ffff8881303e4500: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fa
>ffff8881303e4580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881303e4600: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
ffff8881303e4680: fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc
==================================================================
general protection fault, probably for non-canonical address 0xe0de3c2bc0000058: 0000 [#1] PREEMPT SMP KASAN
KASAN: maybe wild-memory-access in range [0x06f2015e000002c0-0x06f2015e000002c7]
CPU: 0 PID: 1427 Comm: kworker/0:6 Tainted: G B 6.1.129-syzkaller-00051-gc1fd50266bd6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events flush_stashed_error_work
RIP: 0010:kernfs_root fs/kernfs/kernfs-internal.h:68 [inline]
RIP: 0010:kernfs_find_and_get_ns+0x52/0x110 fs/kernfs/dir.c:903
Code: 08 48 89 f8 48 c1 e8 03 42 80 3c 30 00 74 05 e8 c4 bb d3 ff 49 8b 5d 08 48 85 db 49 0f 44 dd 48 83 c3 50 48 89 d8 48 c1 e8 03 <42> 80 3c 30 00 74 08 48 89 df e8 9f bb d3 ff 4c 8b 33 49 83 c6 60
RSP: 0018:ffffc90000c37c68 EFLAGS: 00010203
RAX: 00de402bc0000058 RBX: 06f2015e000002c7 RCX: ffff88811be88000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000c37c90 R08: ffffffff8144b443 R09: fffffbfff0f6e8fd
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffff85d4da20
R13: ffff8881303e4578 R14: dffffc0000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2b08fe CR3: 000000000700f000 CR4: 00000000003506b0
Call Trace:
<TASK>
kernfs_find_and_get include/linux/kernfs.h:614 [inline]
sysfs_notify+0x73/0xd0 fs/sysfs/file.c:190
ext4_notify_error_sysfs+0x25/0x30 fs/ext4/sysfs.c:518
flush_stashed_error_work+0x2fe/0x320 fs/ext4/super.c:-1
process_one_work+0x73d/0xcb0 kernel/workqueue.c:2299
worker_thread+0xa60/0x1260 kernel/workqueue.c:2446
kthread+0x26d/0x300 kernel/kthread.c:386
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:kernfs_root fs/kernfs/kernfs-internal.h:68 [inline]
RIP: 0010:kernfs_find_and_get_ns+0x52/0x110 fs/kernfs/dir.c:903
Code: 08 48 89 f8 48 c1 e8 03 42 80 3c 30 00 74 05 e8 c4 bb d3 ff 49 8b 5d 08 48 85 db 49 0f 44 dd 48 83 c3 50 48 89 d8 48 c1 e8 03 <42> 80 3c 30 00 74 08 48 89 df e8 9f bb d3 ff 4c 8b 33 49 83 c6 60
RSP: 0018:ffffc90000c37c68 EFLAGS: 00010203
RAX: 00de402bc0000058 RBX: 06f2015e000002c7 RCX: ffff88811be88000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000c37c90 R08: ffffffff8144b443 R09: fffffbfff0f6e8fd
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffff85d4da20
R13: ffff8881303e4578 R14: dffffc0000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2b08fe CR3: 000000010ff42000 CR4: 00000000003506b0
----------------
Code disassembly (best guess):
0: 08 48 89 or %cl,-0x77(%rax)
3: f8 clc
4: 48 c1 e8 03 shr $0x3,%rax
8: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1)
d: 74 05 je 0x14
f: e8 c4 bb d3 ff call 0xffd3bbd8
14: 49 8b 5d 08 mov 0x8(%r13),%rbx
18: 48 85 db test %rbx,%rbx
1b: 49 0f 44 dd cmove %r13,%rbx
1f: 48 83 c3 50 add $0x50,%rbx
23: 48 89 d8 mov %rbx,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 48 89 df mov %rbx,%rdi
34: e8 9f bb d3 ff call 0xffd3bbd8
39: 4c 8b 33 mov (%rbx),%r14
3c: 49 83 c6 60 add $0x60,%r14