syzbot

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BUG: KASAN: slab-use-after-free in kernfs_root+0x29a/0x2a0 fs/kernfs/kernfs-internal.h:77
Read of size 8 at addr ffff888076f5e7b0 by task kworker/0:1/11

CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events request_firmware_work_func
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 kernfs_root+0x29a/0x2a0 fs/kernfs/kernfs-internal.h:77
 kernfs_add_one+0x57d/0xaa0 fs/kernfs/dir.c:867
 kernfs_create_dir_ns+0x157/0x2b0 fs/kernfs/dir.c:1130
 sysfs_create_dir_ns+0x13a/0x2b0 fs/sysfs/dir.c:59
 create_dir lib/kobject.c:73 [inline]
 kobject_add_internal+0x2c8/0x930 lib/kobject.c:240
 kobject_add_varg lib/kobject.c:374 [inline]
 kobject_add+0x16a/0x1e0 lib/kobject.c:426
 class_dir_create_and_add drivers/base/core.c:3300 [inline]
 get_device_parent+0x382/0x4c0 drivers/base/core.c:3351
 device_add+0x1ad/0x1970 drivers/base/core.c:3681
 fw_load_sysfs_fallback drivers/base/firmware_loader/fallback.c:86 [inline]
 fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:162 [inline]
 firmware_fallback_sysfs+0x2e2/0xc20 drivers/base/firmware_loader/fallback.c:238
 _request_firmware+0xfd7/0x13c0 drivers/base/firmware_loader/main.c:898
 request_firmware_work_func+0xee/0x440 drivers/base/firmware_loader/main.c:1162
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 11:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4612 [inline]
 slab_alloc_node mm/slub.c:4945 [inline]
 kmem_cache_alloc_noprof+0x26b/0x6a0 mm/slub.c:4959
 __kernfs_new_node+0xd2/0xa10 fs/kernfs/dir.c:665
 kernfs_new_node fs/kernfs/dir.c:751 [inline]
 kernfs_create_dir_ns+0xa6/0x2b0 fs/kernfs/dir.c:1120
 sysfs_create_dir_ns+0x13a/0x2b0 fs/sysfs/dir.c:59
 create_dir lib/kobject.c:73 [inline]
 kobject_add_internal+0x2c8/0x930 lib/kobject.c:240
 kobject_add_varg lib/kobject.c:374 [inline]
 kobject_add+0x16a/0x1e0 lib/kobject.c:426
 class_dir_create_and_add drivers/base/core.c:3300 [inline]
 get_device_parent+0x382/0x4c0 drivers/base/core.c:3351
 device_add+0x1ad/0x1970 drivers/base/core.c:3681
 fw_load_sysfs_fallback drivers/base/firmware_loader/fallback.c:86 [inline]
 fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:162 [inline]
 firmware_fallback_sysfs+0x2e2/0xc20 drivers/base/firmware_loader/fallback.c:238
 _request_firmware+0xfd7/0x13c0 drivers/base/firmware_loader/main.c:898
 request_firmware_work_func+0xee/0x440 drivers/base/firmware_loader/main.c:1162
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 15:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2705 [inline]
 slab_free mm/slub.c:6405 [inline]
 kmem_cache_free+0x127/0x6b0 mm/slub.c:6532
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2897
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 run_ksoftirqd kernel/softirq.c:1076 [inline]
 run_ksoftirqd+0x38/0x60 kernel/softirq.c:1068
 smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Last potentially related work creation:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556
 __call_rcu_common.constprop.0+0xa5/0x9b0 kernel/rcu/tree.c:3159
 kernfs_put.part.0+0x3a6/0xaa0 fs/kernfs/dir.c:618
 kernfs_put fs/kernfs/dir.c:590 [inline]
 __kernfs_remove+0x601/0xb80 fs/kernfs/dir.c:1603
 kernfs_remove fs/kernfs/dir.c:1624 [inline]
 kernfs_remove+0x4b/0x70 fs/kernfs/dir.c:1613
 sysfs_remove_dir+0xc8/0x110 fs/sysfs/dir.c:101
 __kobject_del+0xe2/0x220 lib/kobject.c:604
 kobject_del lib/kobject.c:627 [inline]
 kobject_del+0x3f/0x60 lib/kobject.c:619
 device_del+0x630/0x9b0 drivers/base/core.c:3981
 usb_disconnect+0x5b5/0x9a0 drivers/usb/core/hub.c:2376
 hub_port_connect drivers/usb/core/hub.c:5407 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 port_event drivers/usb/core/hub.c:5871 [inline]
 hub_event+0x1d0c/0x4af0 drivers/usb/core/hub.c:5953
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff888076f5e780
 which belongs to the cache kernfs_node_cache of size 176
The buggy address is located 48 bytes inside of
 freed 176-byte region [ffff888076f5e780, ffff888076f5e830)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x76f5e
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801d2db500 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800110011 00000000f5000000 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 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5605, tgid 5605 (syz-executor), ts 65957005650, free_ts 65950827147
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3294 [inline]
 allocate_slab mm/slub.c:3408 [inline]
 new_slab+0xa2/0x650 mm/slub.c:3454
 refill_objects+0xe3/0x410 mm/slub.c:7338
 refill_sheaf mm/slub.c:2832 [inline]
 __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4703
 alloc_from_pcs mm/slub.c:4801 [inline]
 slab_alloc_node mm/slub.c:4933 [inline]
 kmem_cache_alloc_noprof+0x46e/0x6a0 mm/slub.c:4959
 __kernfs_new_node+0xd2/0xa10 fs/kernfs/dir.c:665
 kernfs_new_node+0x117/0x150 fs/kernfs/dir.c:751
 __kernfs_create_file+0x53/0x350 fs/kernfs/file.c:1050
 sysfs_add_file_mode_ns+0x207/0x3c0 fs/sysfs/file.c:316
 create_files fs/sysfs/group.c:82 [inline]
 internal_create_group+0x593/0xfb0 fs/sysfs/group.c:189
 internal_create_groups+0x9d/0x150 fs/sysfs/group.c:229
 device_add_groups drivers/base/core.c:2907 [inline]
 device_add_attrs drivers/base/core.c:2971 [inline]
 device_add+0x71a/0x1970 drivers/base/core.c:3711
 netdev_register_kobject+0x1a9/0x3d0 net/core/net-sysfs.c:2337
 register_netdevice+0x15b6/0x25a0 net/core/dev.c:11440
page last free pid 5606 tgid 5606 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4612 [inline]
 slab_alloc_node mm/slub.c:4945 [inline]
 kmem_cache_alloc_node_noprof+0x27d/0x6b0 mm/slub.c:5017
 kmalloc_reserve+0x148/0x350 net/core/skbuff.c:615
 __alloc_skb+0x185/0x710 net/core/skbuff.c:715
 alloc_skb include/linux/skbuff.h:1384 [inline]
 nlmsg_new include/net/netlink.h:1055 [inline]
 netlink_ack+0x117/0xb80 net/netlink/af_netlink.c:2493
 netlink_rcv_skb+0x333/0x420 net/netlink/af_netlink.c:2562
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:775 [inline]
 __sock_sendmsg net/socket.c:790 [inline]
 __sys_sendto+0x48b/0x4e0 net/socket.c:2252
 __do_sys_sendto net/socket.c:2259 [inline]
 __se_sys_sendto net/socket.c:2255 [inline]
 __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2255
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888076f5e680: fc fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888076f5e700: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff888076f5e780: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff888076f5e800: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fa fb
 ffff888076f5e880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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