==================================================================
BUG: KASAN: use-after-free in __write_once_size include/linux/compiler.h:295 [inline]
BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:789 [inline]
BUG: KASAN: use-after-free in detach_timer kernel/time/timer.c:824 [inline]
BUG: KASAN: use-after-free in detach_if_pending+0x12d/0x330 kernel/time/timer.c:841
Write of size 8 at addr ffff8881e3d9b1c0 by task kworker/u4:2/328

CPU: 0 PID: 328 Comm: kworker/u4:2 Not tainted 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack+0x1e/0x20 lib/dump_stack.c:77
 dump_stack+0x15b/0x1b8 lib/dump_stack.c:118
 print_address_description+0x8d/0x4c0 mm/kasan/report.c:384
 __kasan_report+0xef/0x120 mm/kasan/report.c:516
 kasan_report+0x30/0x60 mm/kasan/common.c:653
 __asan_report_store8_noabort+0x17/0x20 mm/kasan/generic_report.c:137
 __write_once_size include/linux/compiler.h:295 [inline]
 __hlist_del include/linux/list.h:789 [inline]
 detach_timer kernel/time/timer.c:824 [inline]
 detach_if_pending+0x12d/0x330 kernel/time/timer.c:841
 del_timer+0x75/0xb0 kernel/time/timer.c:1232
 addrconf_del_rs_timer net/ipv6/addrconf.c:305 [inline]
 addrconf_ifdown+0x601/0x17e0 net/ipv6/addrconf.c:3834
 addrconf_notify+0x399/0xeb0 net/ipv6/addrconf.c:3698
 notifier_call_chain kernel/notifier.c:98 [inline]
 __raw_notifier_call_chain kernel/notifier.c:399 [inline]
 raw_notifier_call_chain+0xa0/0x120 kernel/notifier.c:406
 call_netdevice_notifiers_info net/core/dev.c:1670 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:1682 [inline]
 call_netdevice_notifiers net/core/dev.c:1696 [inline]
 dev_close_many+0x2c4/0x440 net/core/dev.c:1439
 rollback_registered_many+0x451/0xf40 net/core/dev.c:8627
 unregister_netdevice_many+0x4b/0x290 net/core/dev.c:9805
 ip_tunnel_delete_nets+0x343/0x390 net/ipv4/ip_tunnel.c:1129
 erspan_exit_batch_net+0x22/0x30 net/ipv4/ip_gre.c:1727
 ops_exit_list net/core/net_namespace.c:187 [inline]
 cleanup_net+0x5fd/0xb40 net/core/net_namespace.c:612
 process_one_work+0x73b/0xcc0 kernel/workqueue.c:2290
 worker_thread+0xa5c/0x13b0 kernel/workqueue.c:2436
 kthread+0x31e/0x3a0 kernel/kthread.c:288
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354

The buggy address belongs to the page:
page:ffffea00078f66c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x8000000000000000()
raw: 8000000000000000 0000000000000000 ffffea00073e0788 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x146dc0(GFP_USER|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_COMP|__GFP_ZERO)
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook mm/page_alloc.c:2165 [inline]
 prep_new_page+0x35e/0x370 mm/page_alloc.c:2171
 get_page_from_freelist+0x1296/0x1310 mm/page_alloc.c:3794
 __alloc_pages_nodemask+0x202/0x4b0 mm/page_alloc.c:4894
 __alloc_pages include/linux/gfp.h:503 [inline]
 __alloc_pages_node include/linux/gfp.h:516 [inline]
 alloc_pages_node include/linux/gfp.h:530 [inline]
 kmalloc_order mm/slab_common.c:1342 [inline]
 kmalloc_order_trace+0x31/0x100 mm/slab_common.c:1358
 kmalloc_large include/linux/slab.h:485 [inline]
 __kmalloc+0x162/0x2f0 mm/slub.c:3902
 __kmalloc_node include/linux/slab.h:422 [inline]
 kmalloc_node include/linux/slab.h:599 [inline]
 kvmalloc_node+0x88/0xf0 mm/util.c:596
 kvmalloc include/linux/mm.h:761 [inline]
 kvzalloc include/linux/mm.h:769 [inline]
 alloc_netdev_mqs+0x88/0xc50 net/core/dev.c:9629
 tun_set_iff+0x535/0xe00 drivers/net/tun.c:2893
 __tun_chr_ioctl+0x771/0x18a0 drivers/net/tun.c:3187
 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:3470
 do_vfs_ioctl+0x753/0x13f0 fs/ioctl.c:47
 ksys_ioctl fs/ioctl.c:742 [inline]
 __do_sys_ioctl fs/ioctl.c:749 [inline]
 __se_sys_ioctl fs/ioctl.c:747 [inline]
 __x64_sys_ioctl+0xe1/0x120 fs/ioctl.c:747
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1176 [inline]
 __free_pages_ok+0x7e4/0x910 mm/page_alloc.c:1438
 free_the_page mm/page_alloc.c:4956 [inline]
 __free_pages+0x8c/0x110 mm/page_alloc.c:4962
 kfree+0x1ca/0x260 mm/slub.c:4068
 kvfree+0x4c/0x50 mm/util.c:625
 netdev_freemem+0x3f/0x60 net/core/dev.c:9583
 netdev_release+0x7f/0xb0 net/core/net-sysfs.c:1743
 device_release+0x70/0x1a0 drivers/base/core.c:1776
 kobject_cleanup lib/kobject.c:716 [inline]
 kobject_release lib/kobject.c:747 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1fe/0x2c0 lib/kobject.c:764
 put_device+0x1f/0x30 drivers/base/core.c:3010
 free_netdev+0x27e/0x320 net/core/dev.c:9746
 tun_set_iff+0x87c/0xe00 drivers/net/tun.c:2924
 __tun_chr_ioctl+0x771/0x18a0 drivers/net/tun.c:3187
 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:3470
 do_vfs_ioctl+0x753/0x13f0 fs/ioctl.c:47
 ksys_ioctl fs/ioctl.c:742 [inline]
 __do_sys_ioctl fs/ioctl.c:749 [inline]
 __se_sys_ioctl fs/ioctl.c:747 [inline]
 __x64_sys_ioctl+0xe1/0x120 fs/ioctl.c:747
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290

Memory state around the buggy address:
 ffff8881e3d9b080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881e3d9b100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881e3d9b180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff8881e3d9b200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881e3d9b280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
device bridge_slave_1 left promiscuous mode
bridge0: port 2(bridge_slave_1) entered disabled state
device bridge_slave_0 left promiscuous mode
bridge0: port 1(bridge_slave_0) entered disabled state