==================================================================
BUG: KASAN: slab-use-after-free in sysfs_remove_file_ns+0x3d/0x70 fs/sysfs/file.c:510
Read of size 8 at addr ffff88805cc4d830 by task syz.9.5029/22637

CPU: 1 UID: 0 PID: 22637 Comm: syz.9.5029 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 sysfs_remove_file_ns+0x3d/0x70 fs/sysfs/file.c:510
 remove_bind_files drivers/base/bus.c:605 [inline]
 bus_remove_driver+0x19b/0x300 drivers/base/bus.c:743
 comedi_device_detach_locked+0x178/0x750 drivers/comedi/drivers.c:207
 do_devconfig_ioctl drivers/comedi/comedi_fops.c:848 [inline]
 comedi_unlocked_ioctl+0xce4/0x1020 drivers/comedi/comedi_fops.c:2178
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc6d25deec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc6d07fc038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc6d2836180 RCX: 00007fc6d25deec9
RDX: 0000000000000000 RSI: 0000000040946400 RDI: 0000000000000009
RBP: 00007fc6d2661f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc6d2836218 R14: 00007fc6d2836180 R15: 00007ffe23ca6068
 </TASK>

Allocated by task 20696:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __do_kmalloc_node mm/slub.c:5604 [inline]
 __kmalloc_noprof+0x233/0x7d0 mm/slub.c:5616
 kmalloc_noprof include/linux/slab.h:961 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 fib6_info_alloc+0x30/0xf0 net/ipv6/ip6_fib.c:155
 ip6_route_info_create+0x142/0x860 net/ipv6/route.c:3809
 addrconf_f6i_alloc+0x1d2/0x450 net/ipv6/route.c:4678
 ipv6_add_addr+0x56e/0x10e0 net/ipv6/addrconf.c:1126
 add_addr+0x8b/0x2f0 net/ipv6/addrconf.c:3201
 add_v4_addrs+0x70c/0xbd0 net/ipv6/addrconf.c:3263
 addrconf_sit_config net/ipv6/addrconf.c:3516 [inline]
 addrconf_init_auto_addrs+0x2c4/0xa30 net/ipv6/addrconf.c:3554
 addrconf_notify+0xacc/0x1010 net/ipv6/addrconf.c:3740
 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
 call_netdevice_notifiers net/core/dev.c:2281 [inline]
 __dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1
 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9705
 do_setlink+0xc55/0x41c0 net/core/rtnetlink.c:3151
 rtnl_changelink net/core/rtnetlink.c:3769 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3928 [inline]
 rtnl_newlink+0x1619/0x1c80 net/core/rtnetlink.c:4065
 rtnetlink_rcv_msg+0x7cc/0xb70 net/core/rtnetlink.c:6954
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x846/0xa10 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 __sys_sendto+0x3c7/0x520 net/socket.c:2244
 __do_sys_sendto net/socket.c:2251 [inline]
 __se_sys_sendto net/socket.c:2247 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2247
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 20:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587
 kasan_save_free_info mm/kasan/kasan.h:406 [inline]
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2515 [inline]
 slab_free mm/slub.c:6574 [inline]
 kfree+0x197/0x950 mm/slub.c:6781
 rcu_do_batch kernel/rcu/tree.c:2605 [inline]
 rcu_core kernel/rcu/tree.c:2861 [inline]
 rcu_cpu_kthread+0xbf6/0x1b50 kernel/rcu/tree.c:2949
 smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:160
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4b9/0x870 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+0x3e/0x60 mm/kasan/common.c:56
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:559
 __call_rcu_common kernel/rcu/tree.c:3123 [inline]
 call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3243
 call_rcu_hurry include/linux/rcupdate.h:115 [inline]
 fib6_info_release include/net/ip6_fib.h:344 [inline]
 __ip6_del_rt+0x132/0x1a0 net/ipv6/route.c:3969
 ip6_del_rt+0xb3/0x100 net/ipv6/route.c:3980
 __ipv6_ifa_notify+0x5c7/0xac0 net/ipv6/addrconf.c:6310
 addrconf_ifdown+0xfb0/0x18c0 net/ipv6/addrconf.c:3977
 addrconf_notify+0x1bc/0x1010 net/ipv6/addrconf.c:-1
 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
 call_netdevice_notifiers net/core/dev.c:2281 [inline]
 netif_close_many+0x29c/0x410 net/core/dev.c:1784
 unregister_netdevice_many_notify+0x7b9/0x1fe0 net/core/dev.c:12224
 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
 ops_undo_list+0x3dc/0x990 net/core/net_namespace.c:248
 cleanup_net+0x4de/0x820 net/core/net_namespace.c:695
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4b9/0x870 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 ffff88805cc4d800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 48 bytes inside of
 freed 512-byte region [ffff88805cc4d800, ffff88805cc4da00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5cc4c
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813ff26c80 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813ff26c80 0000000000000000 dead000000000001
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 0080000000000002 ffffea0001731301 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 9, tgid 9 (kworker/0:0), ts 91110410014, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850
 prep_new_page mm/page_alloc.c:1858 [inline]
 get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3884
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183
 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:3031 [inline]
 allocate_slab+0x96/0x3a0 mm/slub.c:3204
 new_slab mm/slub.c:3258 [inline]
 ___slab_alloc+0xb12/0x13f0 mm/slub.c:4628
 __slab_alloc+0xc6/0x1f0 mm/slub.c:4747
 __slab_alloc_node mm/slub.c:4823 [inline]
 slab_alloc_node mm/slub.c:5234 [inline]
 __do_kmalloc_node mm/slub.c:5603 [inline]
 __kmalloc_noprof+0x14b/0x7d0 mm/slub.c:5616
 kmalloc_noprof include/linux/slab.h:961 [inline]
 switchdev_deferred_enqueue+0x2d/0x260 net/switchdev/switchdev.c:117
 br_switchdev_host_mdb_one net/bridge/br_switchdev.c:567 [inline]
 br_switchdev_host_mdb net/bridge/br_switchdev.c:582 [inline]
 br_switchdev_mdb_notify+0x25e/0x410 net/bridge/br_switchdev.c:657
 __br_mdb_notify+0x73/0x970 net/bridge/br_mdb.c:532
 br_multicast_host_join net/bridge/br_multicast.c:1482 [inline]
 __br_multicast_add_group+0x84f/0xa30 net/bridge/br_multicast.c:1525
 br_multicast_add_group net/bridge/br_multicast.c:1569 [inline]
 br_ip6_multicast_add_group net/bridge/br_multicast.c:1621 [inline]
 br_ip6_multicast_mld2_report net/bridge/br_multicast.c:3047 [inline]
 br_multicast_ipv6_rcv net/bridge/br_multicast.c:3985 [inline]
 br_multicast_rcv+0x3a5f/0x74b0 net/bridge/br_multicast.c:4043
 br_dev_xmit+0xaf7/0x1840 net/bridge/br_device.c:98
 __netdev_start_xmit include/linux/netdevice.h:5248 [inline]
 netdev_start_xmit include/linux/netdevice.h:5257 [inline]
 xmit_one net/core/dev.c:3845 [inline]
 dev_hard_start_xmit+0x2ed/0x870 net/core/dev.c:3861
 __dev_queue_xmit+0x1b50/0x3b70 net/core/dev.c:4763
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88805cc4d700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88805cc4d780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88805cc4d800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff88805cc4d880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805cc4d900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================