[v5.15] KASAN: use-after-free Read in kernfs_next_descendant_post (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3a5928702e71 Linux 5.15.167
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11d6ffd0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=4d3fd5cca89ae935
dashboard link: https://syzkaller.appspot.com/bug?extid=7588e91b86d83478fa35
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ef5025f3d708/disk-3a592870.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/776fbdad3aa8/vmlinux-3a592870.xz
kernel image: https://storage.googleapis.com/syzbot-assets/79541db5bd16/bzImage-3a592870.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7588e9...@syzkaller.appspotmail.com

usb 5-1: Falling back to sysfs fallback for: ueagle-atm/eagleII.fw
==================================================================
BUG: KASAN: use-after-free in kernfs_type include/linux/kernfs.h:294 [inline]
BUG: KASAN: use-after-free in kernfs_leftmost_descendant fs/kernfs/dir.c:1251 [inline]
BUG: KASAN: use-after-free in kernfs_next_descendant_post+0x184/0x200 fs/kernfs/dir.c:1282
Read of size 2 at addr ffff888061fe68c0 by task kworker/1:3/2989

CPU: 1 PID: 2989 Comm: kworker/1:3 Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events request_firmware_work_func
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
print_address_description+0x63/0x3b0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:434 [inline]
kasan_report+0x16b/0x1c0 mm/kasan/report.c:451
kernfs_type include/linux/kernfs.h:294 [inline]
kernfs_leftmost_descendant fs/kernfs/dir.c:1251 [inline]
kernfs_next_descendant_post+0x184/0x200 fs/kernfs/dir.c:1282
kernfs_activate+0x28/0x200 fs/kernfs/dir.c:1317
kernfs_add_one+0x4f3/0x640 fs/kernfs/dir.c:788
kernfs_create_dir_ns+0xd5/0x120 fs/kernfs/dir.c:1015
sysfs_create_dir_ns+0x185/0x390 fs/sysfs/dir.c:59
create_dir lib/kobject.c:89 [inline]
kobject_add_internal+0x6e0/0xe00 lib/kobject.c:263
kobject_add_varg lib/kobject.c:398 [inline]
kobject_add+0x14e/0x210 lib/kobject.c:450
class_dir_create_and_add drivers/base/core.c:2969 [inline]
get_device_parent+0x391/0x400 drivers/base/core.c:3024
device_add+0x336/0xfd0 drivers/base/core.c:3336
fw_load_sysfs_fallback drivers/base/firmware_loader/fallback.c:507 [inline]
fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:583 [inline]
firmware_fallback_sysfs+0x3f0/0xc90 drivers/base/firmware_loader/fallback.c:659
_request_firmware+0xbb1/0x1200 drivers/base/firmware_loader/main.c:848
request_firmware_work_func+0x126/0x270 drivers/base/firmware_loader/main.c:1097
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>

Allocated by task 2989:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
__kasan_slab_alloc+0x8e/0xc0 mm/kasan/common.c:467
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook+0x53/0x380 mm/slab.h:519
slab_alloc_node mm/slub.c:3220 [inline]
slab_alloc mm/slub.c:3228 [inline]
kmem_cache_alloc+0xf3/0x280 mm/slub.c:3233
kmem_cache_zalloc include/linux/slab.h:711 [inline]
__kernfs_new_node+0xdb/0x750 fs/kernfs/dir.c:593
kernfs_new_node+0x136/0x230 fs/kernfs/dir.c:669
kernfs_create_dir_ns+0x3f/0x120 fs/kernfs/dir.c:1005
sysfs_create_dir_ns+0x185/0x390 fs/sysfs/dir.c:59
create_dir lib/kobject.c:89 [inline]
kobject_add_internal+0x6e0/0xe00 lib/kobject.c:263
kobject_add_varg lib/kobject.c:398 [inline]
kobject_add+0x14e/0x210 lib/kobject.c:450
class_dir_create_and_add drivers/base/core.c:2969 [inline]
get_device_parent+0x391/0x400 drivers/base/core.c:3024
device_add+0x336/0xfd0 drivers/base/core.c:3336
fw_load_sysfs_fallback drivers/base/firmware_loader/fallback.c:507 [inline]
fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:583 [inline]
firmware_fallback_sysfs+0x3f0/0xc90 drivers/base/firmware_loader/fallback.c:659
_request_firmware+0xbb1/0x1200 drivers/base/firmware_loader/main.c:848
request_firmware_work_func+0x126/0x270 drivers/base/firmware_loader/main.c:1097
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Freed by task 1725:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4b/0x80 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
____kasan_slab_free+0xd8/0x120 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1705 [inline]
slab_free_freelist_hook+0xdd/0x160 mm/slub.c:1731
slab_free mm/slub.c:3499 [inline]
kmem_cache_free+0x91/0x1f0 mm/slub.c:3515
kernfs_put+0x325/0x4a0 fs/kernfs/dir.c:547
__kernfs_remove+0x99e/0xc80 fs/kernfs/dir.c:1393
kernfs_remove+0x1d/0x30 fs/kernfs/dir.c:1406
__kobject_del+0xe2/0x310 lib/kobject.c:628
kobject_del+0x41/0x60 lib/kobject.c:651
device_del+0x9fe/0xbd0 drivers/base/core.c:3615
usb_disconnect+0x58f/0x8c0 drivers/usb/core/hub.c:2274
hub_port_connect drivers/usb/core/hub.c:5299 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5595 [inline]
port_event drivers/usb/core/hub.c:5741 [inline]
hub_event+0x1d58/0x54c0 drivers/usb/core/hub.c:5823
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
process_scheduled_works kernel/workqueue.c:2373 [inline]
worker_thread+0xdcf/0x1280 kernel/workqueue.c:2459
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

The buggy address belongs to the object at ffff888061fe6828
which belongs to the cache kernfs_node_cache of size 168
The buggy address is located 152 bytes inside of
168-byte region [ffff888061fe6828, ffff888061fe68d0)
The buggy address belongs to the page:
page:ffffea000187f980 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x61fe6
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 0000000000000000 0000000c00000001 ffff8880171f2b40
raw: 0000000000000000 0000000080110011 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 3571, ts 45736226204, free_ts 10539269925
prep_new_page mm/page_alloc.c:2426 [inline]
get_page_from_freelist+0x322a/0x33c0 mm/page_alloc.c:4159
__alloc_pages+0x272/0x700 mm/page_alloc.c:5423
alloc_slab_page mm/slub.c:1775 [inline]
allocate_slab mm/slub.c:1912 [inline]
new_slab+0xbb/0x4b0 mm/slub.c:1975
___slab_alloc+0x6f6/0xe10 mm/slub.c:3008
__slab_alloc mm/slub.c:3095 [inline]
slab_alloc_node mm/slub.c:3186 [inline]
slab_alloc mm/slub.c:3228 [inline]
kmem_cache_alloc+0x18e/0x280 mm/slub.c:3233
kmem_cache_zalloc include/linux/slab.h:711 [inline]
__kernfs_new_node+0xdb/0x750 fs/kernfs/dir.c:593
kernfs_new_node+0x136/0x230 fs/kernfs/dir.c:669
__kernfs_create_file+0x45/0x2e0 fs/kernfs/file.c:985
sysfs_add_file_mode_ns+0x308/0x3e0 fs/sysfs/file.c:317
create_files fs/sysfs/group.c:64 [inline]
internal_create_group+0x573/0xf00 fs/sysfs/group.c:149
netdev_queue_add_kobject net/core/net-sysfs.c:1672 [inline]
netdev_queue_update_kobjects+0x1a8/0x3f0 net/core/net-sysfs.c:1711
register_queue_kobjects net/core/net-sysfs.c:1772 [inline]
netdev_register_kobject+0x263/0x310 net/core/net-sysfs.c:2018
register_netdevice+0x108c/0x1720 net/core/dev.c:10357
veth_newlink+0x72e/0xe20 drivers/net/veth.c:1683
__rtnl_newlink net/core/rtnetlink.c:3492 [inline]
rtnl_newlink+0x14e1/0x2070 net/core/rtnetlink.c:3540
rtnetlink_rcv_msg+0x993/0xee0 net/core/rtnetlink.c:5618
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1340 [inline]
free_pcp_prepare mm/page_alloc.c:1391 [inline]
free_unref_page_prepare+0xc34/0xcf0 mm/page_alloc.c:3317
free_unref_page+0x95/0x2d0 mm/page_alloc.c:3396
free_contig_range+0x95/0xf0 mm/page_alloc.c:9342
destroy_args+0xfe/0x980 mm/debug_vm_pgtable.c:1018
debug_vm_pgtable+0x40d/0x470 mm/debug_vm_pgtable.c:1331
do_one_initcall+0x22b/0x7a0 init/main.c:1302
do_initcall_level+0x157/0x210 init/main.c:1375
do_initcalls+0x49/0x90 init/main.c:1391
kernel_init_freeable+0x425/0x5c0 init/main.c:1615
kernel_init+0x19/0x290 init/main.c:1506
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Memory state around the buggy address:
ffff888061fe6780: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
ffff888061fe6800: fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb fb
>ffff888061fe6880: fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc
^
ffff888061fe6900: fc fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888061fe6980: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fa
==================================================================


---
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 syzk...@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

[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.