syzbot

device bridge_slave_0 left promiscuous mode
bridge0: port 1(bridge_slave_0) entered disabled state
device veth1_macvtap left promiscuous mode
device veth0_vlan left promiscuous mode
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: use-after-free in atomic_try_cmpxchg_acquire include/asm-generic/atomic-instrumented.h:705 [inline]
BUG: KASAN: use-after-free in queued_spin_lock include/asm-generic/qspinlock.h:82 [inline]
BUG: KASAN: use-after-free in do_raw_spin_lock include/linux/spinlock.h:183 [inline]
BUG: KASAN: use-after-free in __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline]
BUG: KASAN: use-after-free in _raw_spin_lock_bh+0x81/0xe0 kernel/locking/spinlock.c:175
Write of size 4 at addr ffff88810bbe0414 by task kworker/u4:4/348

CPU: 0 PID: 348 Comm: kworker/u4:4 Not tainted 5.10.238-syzkaller-00282-gd76d4cd0623a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x169/0x1d8 lib/dump_stack.c:118
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0xe2/0x130 mm/kasan/report.c:452
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x280/0x290 mm/kasan/generic.c:189
 __kasan_check_write+0x14/0x20 mm/kasan/shadow.c:37
 instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
 atomic_try_cmpxchg_acquire include/asm-generic/atomic-instrumented.h:705 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:82 [inline]
 do_raw_spin_lock include/linux/spinlock.h:183 [inline]
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline]
 _raw_spin_lock_bh+0x81/0xe0 kernel/locking/spinlock.c:175
 spin_lock_bh include/linux/spinlock.h:359 [inline]
 __ip6_del_rt+0x8f/0x150 net/ipv6/route.c:3791
 ip6_del_rt+0xb0/0xf0 net/ipv6/route.c:3807
 __remove_nexthop_fib+0x1e8/0x260 net/ipv4/nexthop.c:885
 __remove_nexthop net/ipv4/nexthop.c:893 [inline]
 remove_nexthop+0x75/0x4d0 net/ipv4/nexthop.c:919
 remove_nh_grp_entry net/ipv4/nexthop.c:797 [inline]
 remove_nexthop_from_groups+0x193/0xe40 net/ipv4/nexthop.c:846
 __remove_nexthop net/ipv4/nexthop.c:904 [inline]
 remove_nexthop+0x38a/0x4d0 net/ipv4/nexthop.c:919
 flush_all_nexthops net/ipv4/nexthop.c:1237 [inline]
 nexthop_net_exit+0x3a/0xa0 net/ipv4/nexthop.c:2012
 ops_exit_list net/core/net_namespace.c:185 [inline]
 cleanup_net+0x586/0xb70 net/core/net_namespace.c:609
 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301
 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447
 kthread+0x346/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

Allocated by task 352:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:430 [inline]
 ____kasan_kmalloc mm/kasan/common.c:509 [inline]
 __kasan_kmalloc+0xda/0x110 mm/kasan/common.c:518
 kasan_kmalloc include/linux/kasan.h:254 [inline]
 kmem_cache_alloc_trace+0x184/0x2e0 mm/slub.c:2974
 kmalloc include/linux/slab.h:552 [inline]
 kzalloc include/linux/slab.h:664 [inline]
 fib6_net_init+0x217/0x880 net/ipv6/ip6_fib.c:2376
 ops_init+0x1ba/0x4a0 net/core/net_namespace.c:144
 setup_net+0x36d/0xb50 net/core/net_namespace.c:345
 copy_net_ns+0x314/0x520 net/core/net_namespace.c:486
 create_new_namespaces+0x3a2/0x650 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x120/0x170 kernel/nsproxy.c:231
 ksys_unshare+0x4ac/0x7d0 kernel/fork.c:3156
 __do_sys_unshare kernel/fork.c:3224 [inline]
 __se_sys_unshare kernel/fork.c:3222 [inline]
 __x64_sys_unshare+0x38/0x40 kernel/fork.c:3222
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Freed by task 348:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370
 kasan_slab_free include/linux/kasan.h:220 [inline]
 slab_free_hook mm/slub.c:1595 [inline]
 slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1621
 slab_free mm/slub.c:3203 [inline]
 kfree+0xc0/0x270 mm/slub.c:4191
 fib6_free_table net/ipv6/ip6_fib.c:214 [inline]
 fib6_net_exit+0x270/0x300 net/ipv6/ip6_fib.c:2430
 ops_exit_list net/core/net_namespace.c:185 [inline]
 cleanup_net+0x586/0xb70 net/core/net_namespace.c:609
 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301
 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447
 kthread+0x346/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

The buggy address belongs to the object at ffff88810bbe0400
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 20 bytes inside of
 128-byte region [ffff88810bbe0400, ffff88810bbe0480)
The buggy address belongs to the page:
page:ffffea00042ef800 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88810bbe0100 pfn:0x10bbe0
flags: 0x4000000000000200(slab)
raw: 4000000000000200 ffffea00042f0108 ffffea00042eee48 ffff888100043500
raw: ffff88810bbe0100 0000000000100009 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 1, ts 3587043019, free_ts 0
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x179/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5357
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1808 [inline]
 new_slab+0x84/0x3f0 mm/slub.c:1869
 new_slab_objects mm/slub.c:2627 [inline]
 ___slab_alloc+0x2a6/0x450 mm/slub.c:2791
 __slab_alloc+0x63/0xa0 mm/slub.c:2831
 slab_alloc_node mm/slub.c:2913 [inline]
 slab_alloc mm/slub.c:2955 [inline]
 kmem_cache_alloc_trace+0x1b3/0x2e0 mm/slub.c:2972
 kmalloc include/linux/slab.h:552 [inline]
 kzalloc include/linux/slab.h:664 [inline]
 call_usermodehelper_setup+0x71/0x1d0 kernel/umh.c:363
 kobject_uevent_env+0x639/0x700 lib/kobject_uevent.c:629
 kobject_uevent+0x1d/0x30 lib/kobject_uevent.c:657
 driver_register+0x3f4/0x440 drivers/base/driver.c:248
 __hid_register_driver+0x12a/0x190 drivers/hid/hid-core.c:2571
 belkin_driver_init+0x1e/0x20 drivers/hid/hid-belkin.c:86
 do_one_initcall+0x187/0x510 init/main.c:1197
 do_initcall_level+0x16f/0x2cf init/main.c:1270
 do_initcalls+0x50/0x92 init/main.c:1286
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88810bbe0300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88810bbe0380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88810bbe0400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88810bbe0480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810bbe0500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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