[syzbot] KASAN: use-after-free Read in kernfs_activate (2)

From: syzbot
Date: Sun Nov 13 2022 - 10:41:03 EST

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Hello,

syzbot found the following issue on:

HEAD commit: 59f2f4b8a757 fs/userfaultfd: Fix maple tree iterator in us..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14e836fa880000
kernel config: https://syzkaller.appspot.com/x/.config?x=480ba0fb2fd243ac
dashboard link: https://syzkaller.appspot.com/bug?extid=782984d6f1701b526edb
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/619de907b82c/disk-59f2f4b8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bcd0dc7d69ef/vmlinux-59f2f4b8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a8dbe0bc7228/bzImage-59f2f4b8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+782984d6f1701b526edb@xxxxxxxxxxxxxxxxxxxxxxxxx

usb 4-1: Direct firmware load for ueagle-atm/eagleII.fw failed with error -2
usb 4-1: Falling back to sysfs fallback for: ueagle-atm/eagleII.fw
==================================================================
BUG: KASAN: use-after-free in kernfs_root fs/kernfs/kernfs-internal.h:66 [inline]
BUG: KASAN: use-after-free in kernfs_next_descendant_post fs/kernfs/dir.c:1289 [inline]
BUG: KASAN: use-after-free in kernfs_activate+0xd0/0x3a0 fs/kernfs/dir.c:1344
Read of size 8 at addr ffff888079194b10 by task kworker/1:12/5383

CPU: 1 PID: 5383 Comm: kworker/1:12 Not tainted 6.1.0-rc4-syzkaller-00011-g59f2f4b8a757 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: events request_firmware_work_func
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
print_address_description+0x74/0x340 mm/kasan/report.c:284
print_report+0x107/0x220 mm/kasan/report.c:395
kasan_report+0x139/0x170 mm/kasan/report.c:495
kernfs_root fs/kernfs/kernfs-internal.h:66 [inline]
kernfs_next_descendant_post fs/kernfs/dir.c:1289 [inline]
kernfs_activate+0xd0/0x3a0 fs/kernfs/dir.c:1344
kernfs_add_one+0x465/0x560 fs/kernfs/dir.c:776
kernfs_create_dir_ns+0x1bf/0x220 fs/kernfs/dir.c:1021
sysfs_create_dir_ns+0x181/0x390 fs/sysfs/dir.c:59
create_dir lib/kobject.c:63 [inline]
kobject_add_internal+0x6dd/0xd10 lib/kobject.c:223
kobject_add_varg lib/kobject.c:358 [inline]
kobject_add+0x14c/0x210 lib/kobject.c:410
device_add+0x47d/0xf90 drivers/base/core.c:3452
fw_load_sysfs_fallback+0xd4/0x5e0 drivers/base/firmware_loader/fallback.c:82
fw_load_from_user_helper+0x12d/0x1f0 drivers/base/firmware_loader/fallback.c:158
_request_firmware+0x446/0x6a0 drivers/base/firmware_loader/main.c:856
request_firmware_work_func+0x125/0x270 drivers/base/firmware_loader/main.c:1105
process_one_work+0x81c/0xd10 kernel/workqueue.c:2289
worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
kthread+0x266/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>

Allocated by task 5383:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4c/0x70 mm/kasan/common.c:52
__kasan_slab_alloc+0x65/0x70 mm/kasan/common.c:325
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slab.h:737 [inline]
slab_alloc_node mm/slub.c:3398 [inline]
slab_alloc mm/slub.c:3406 [inline]
__kmem_cache_alloc_lru mm/slub.c:3413 [inline]
kmem_cache_alloc+0x1cc/0x300 mm/slub.c:3422
kmem_cache_zalloc include/linux/slab.h:702 [inline]
__kernfs_new_node+0xdb/0x730 fs/kernfs/dir.c:603
kernfs_new_node fs/kernfs/dir.c:665 [inline]
kernfs_create_dir_ns+0x90/0x220 fs/kernfs/dir.c:1011
sysfs_create_dir_ns+0x181/0x390 fs/sysfs/dir.c:59
create_dir lib/kobject.c:63 [inline]
kobject_add_internal+0x6dd/0xd10 lib/kobject.c:223
kobject_add_varg lib/kobject.c:358 [inline]
kobject_add+0x14c/0x210 lib/kobject.c:410
device_add+0x47d/0xf90 drivers/base/core.c:3452
fw_load_sysfs_fallback+0xd4/0x5e0 drivers/base/firmware_loader/fallback.c:82
fw_load_from_user_helper+0x12d/0x1f0 drivers/base/firmware_loader/fallback.c:158
_request_firmware+0x446/0x6a0 drivers/base/firmware_loader/main.c:856
request_firmware_work_func+0x125/0x270 drivers/base/firmware_loader/main.c:1105
process_one_work+0x81c/0xd10 kernel/workqueue.c:2289
worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
kthread+0x266/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

Freed by task 3754:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4c/0x70 mm/kasan/common.c:52
kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:511
____kasan_slab_free+0xd6/0x120 mm/kasan/common.c:236
kasan_slab_free include/linux/kasan.h:177 [inline]
slab_free_hook mm/slub.c:1724 [inline]
slab_free_freelist_hook+0x12e/0x1a0 mm/slub.c:1750
slab_free mm/slub.c:3661 [inline]
kmem_cache_free+0x94/0x1d0 mm/slub.c:3683
kernfs_put+0x340/0x490 fs/kernfs/dir.c:557
__kernfs_remove+0x980/0xa90 fs/kernfs/dir.c:1443
kernfs_remove+0x76/0x90 fs/kernfs/dir.c:1463
__kobject_del+0xdc/0x300 lib/kobject.c:588
kobject_del+0x41/0x60 lib/kobject.c:611
device_del+0xa10/0xbe0 drivers/base/core.c:3715
usb_disconnect+0x56e/0x890 drivers/usb/core/hub.c:2261
hub_port_connect+0x296/0x2910 drivers/usb/core/hub.c:5197
hub_port_connect_change+0x619/0xbe0 drivers/usb/core/hub.c:5497
port_event+0xec6/0x13b0 drivers/usb/core/hub.c:5653
hub_event+0x5c1/0xd80 drivers/usb/core/hub.c:5735
process_one_work+0x81c/0xd10 kernel/workqueue.c:2289
process_scheduled_works kernel/workqueue.c:2352 [inline]
worker_thread+0xe16/0x1330 kernel/workqueue.c:2438
kthread+0x266/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

The buggy address belongs to the object at ffff888079194ae0
which belongs to the cache kernfs_node_cache of size 168
The buggy address is located 48 bytes inside of
168-byte region [ffff888079194ae0, ffff888079194b88)

The buggy address belongs to the physical page:
page:ffffea0001e46500 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x79194
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea00009ddc80 dead000000000004 ffff8880121d5dc0
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 3659, tgid 3659 (syz-executor.4), ts 217350520729, free_ts 217156331022
prep_new_page mm/page_alloc.c:2539 [inline]
get_page_from_freelist+0x72b/0x7a0 mm/page_alloc.c:4288
__alloc_pages+0x259/0x560 mm/page_alloc.c:5555
alloc_slab_page+0x70/0xf0 mm/slub.c:1794
allocate_slab+0x5e/0x4b0 mm/slub.c:1939
new_slab mm/slub.c:1992 [inline]
___slab_alloc+0x7f4/0xeb0 mm/slub.c:3180
__slab_alloc mm/slub.c:3279 [inline]
slab_alloc_node mm/slub.c:3364 [inline]
slab_alloc mm/slub.c:3406 [inline]
__kmem_cache_alloc_lru mm/slub.c:3413 [inline]
kmem_cache_alloc+0x24c/0x300 mm/slub.c:3422
kmem_cache_zalloc include/linux/slab.h:702 [inline]
__kernfs_new_node+0xdb/0x730 fs/kernfs/dir.c:603
kernfs_new_node fs/kernfs/dir.c:665 [inline]
kernfs_create_dir_ns+0x90/0x220 fs/kernfs/dir.c:1011
sysfs_create_dir_ns+0x181/0x390 fs/sysfs/dir.c:59
create_dir lib/kobject.c:63 [inline]
kobject_add_internal+0x6dd/0xd10 lib/kobject.c:223
kset_register lib/kobject.c:846 [inline]
kset_create_and_add+0x201/0x280 lib/kobject.c:983
register_queue_kobjects net/core/net-sysfs.c:1766 [inline]
netdev_register_kobject+0x1a2/0x310 net/core/net-sysfs.c:2019
register_netdevice+0x136c/0x1a20 net/core/dev.c:10057
veth_newlink+0x638/0xd10 drivers/net/veth.c:1764
rtnl_newlink_create net/core/rtnetlink.c:3364 [inline]
__rtnl_newlink net/core/rtnetlink.c:3581 [inline]
rtnl_newlink+0x14ed/0x2060 net/core/rtnetlink.c:3594
rtnetlink_rcv_msg+0x7b8/0xe90 net/core/rtnetlink.c:6091
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1459 [inline]
free_pcp_prepare+0x80c/0x8f0 mm/page_alloc.c:1509
free_unref_page_prepare mm/page_alloc.c:3387 [inline]
free_unref_page+0x7d/0x630 mm/page_alloc.c:3483
free_slab mm/slub.c:2031 [inline]
discard_slab mm/slub.c:2037 [inline]
__unfreeze_partials+0x1ab/0x200 mm/slub.c:2586
put_cpu_partial+0x116/0x180 mm/slub.c:2662
qlist_free_all+0x2b/0x70 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x169/0x180 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0x1f/0x70 mm/kasan/common.c:302
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slab.h:737 [inline]
slab_alloc_node mm/slub.c:3398 [inline]
__kmem_cache_alloc_node+0x1d7/0x310 mm/slub.c:3437
kmalloc_trace+0x26/0x60 mm/slab_common.c:1046
kmalloc include/linux/slab.h:576 [inline]
kzalloc include/linux/slab.h:712 [inline]
kobject_uevent_env+0x33a/0x8e0 lib/kobject_uevent.c:524
__kobject_del+0xcd/0x300 lib/kobject.c:585
kobject_cleanup+0x25d/0x470 lib/kobject.c:664
netdev_queue_update_kobjects+0x417/0x4c0 net/core/net-sysfs.c:1733
netif_set_real_num_tx_queues+0x16d/0x880 net/core/dev.c:2893
veth_init_queues+0x81/0x170 drivers/net/veth.c:1687
veth_newlink+0xa59/0xd10 drivers/net/veth.c:1813

Memory state around the buggy address:
ffff888079194a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888079194a80: fb fb fb fb fc fc fc fc fc fc fc fc fa fb fb fb
>ffff888079194b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888079194b80: fb fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00
ffff888079194c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc
==================================================================

---
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Next message: Christophe JAILLET: "[PATCH] wifi: rtw89: Fix some error handling path in rtw89_wow_enable()"
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