==================================================================
BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:791 [inline]
BUG: KASAN: use-after-free in detach_timer kernel/time/timer.c:824 [inline]
BUG: KASAN: use-after-free in expire_timers kernel/time/timer.c:1452 [inline]
BUG: KASAN: use-after-free in __run_timers+0x7be/0xbe0 kernel/time/timer.c:1787
Write of size 8 at addr ffff8881d9d8b1c8 by task syz-executor.1/12457

CPU: 1 PID: 12457 Comm: syz-executor.1 Not tainted 5.4.265-syzkaller-00001-g1b3143b9b166 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1d8/0x241 lib/dump_stack.c:118
 print_address_description+0x8c/0x600 mm/kasan/report.c:384
 __kasan_report+0xf3/0x120 mm/kasan/report.c:516
 kasan_report+0x30/0x60 mm/kasan/common.c:653
 __hlist_del include/linux/list.h:791 [inline]
 detach_timer kernel/time/timer.c:824 [inline]
 expire_timers kernel/time/timer.c:1452 [inline]
 __run_timers+0x7be/0xbe0 kernel/time/timer.c:1787
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1800
 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x195/0x1c0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:538 [inline]
 smp_apic_timer_interrupt+0x11a/0x460 arch/x86/kernel/apic/apic.c:1149
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834
 </IRQ>

Allocated by task 12472:
 save_stack mm/kasan/common.c:70 [inline]
 set_track mm/kasan/common.c:78 [inline]
 __kasan_kmalloc+0x171/0x210 mm/kasan/common.c:529
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc_node mm/slub.c:2829 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 __kmalloc_track_caller+0x100/0x2b0 mm/slub.c:4449
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0xb4/0x4d0 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1080 [inline]
 alloc_uevent_skb+0x74/0x220 lib/kobject_uevent.c:290
 uevent_net_broadcast_tagged lib/kobject_uevent.c:351 [inline]
 kobject_uevent_net_broadcast+0x176/0x560 lib/kobject_uevent.c:412
 kobject_uevent_env+0x54d/0x710 lib/kobject_uevent.c:593
 rx_queue_add_kobject net/core/net-sysfs.c:988 [inline]
 net_rx_queue_update_kobjects+0x1c2/0x420 net/core/net-sysfs.c:1010
 register_queue_kobjects net/core/net-sysfs.c:1632 [inline]
 netdev_register_kobject+0x222/0x310 net/core/net-sysfs.c:1858
 register_netdevice+0xbc5/0x12a0 net/core/dev.c:9182
 register_netdev+0x37/0x50 net/core/dev.c:9311
 loopback_net_init+0x6f/0x140 drivers/net/loopback.c:214
 ops_init+0x1d4/0x4a0 net/core/net_namespace.c:138
 setup_net+0x214/0x990 net/core/net_namespace.c:345
 copy_net_ns+0x30f/0x510 net/core/net_namespace.c:486
 create_new_namespaces+0x47a/0x570 kernel/nsproxy.c:103
 copy_namespaces+0x169/0x1b0 kernel/nsproxy.c:161
 copy_process+0x12da/0x3230 kernel/fork.c:2055
 _do_fork+0x197/0x900 kernel/fork.c:2399
 __do_sys_clone kernel/fork.c:2557 [inline]
 __se_sys_clone kernel/fork.c:2538 [inline]
 __x64_sys_clone+0x26b/0x2c0 kernel/fork.c:2538
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Freed by task 12472:
 save_stack mm/kasan/common.c:70 [inline]
 set_track mm/kasan/common.c:78 [inline]
 kasan_set_free_info mm/kasan/common.c:345 [inline]
 __kasan_slab_free+0x1b5/0x270 mm/kasan/common.c:487
 slab_free_hook mm/slub.c:1455 [inline]
 slab_free_freelist_hook mm/slub.c:1494 [inline]
 slab_free mm/slub.c:3080 [inline]
 kfree+0x123/0x370 mm/slub.c:4071
 skb_release_all net/core/skbuff.c:675 [inline]
 __kfree_skb net/core/skbuff.c:689 [inline]
 consume_skb+0xa5/0x2a0 net/core/skbuff.c:849
 netlink_broadcast_filtered+0x115f/0x1280 net/netlink/af_netlink.c:1531
 netlink_broadcast+0x35/0x50 net/netlink/af_netlink.c:1553
 uevent_net_broadcast_tagged lib/kobject_uevent.c:372 [inline]
 kobject_uevent_net_broadcast+0x4be/0x560 lib/kobject_uevent.c:412
 kobject_uevent_env+0x54d/0x710 lib/kobject_uevent.c:593
 rx_queue_add_kobject net/core/net-sysfs.c:988 [inline]
 net_rx_queue_update_kobjects+0x1c2/0x420 net/core/net-sysfs.c:1010
 register_queue_kobjects net/core/net-sysfs.c:1632 [inline]
 netdev_register_kobject+0x222/0x310 net/core/net-sysfs.c:1858
 register_netdevice+0xbc5/0x12a0 net/core/dev.c:9182
 register_netdev+0x37/0x50 net/core/dev.c:9311
 loopback_net_init+0x6f/0x140 drivers/net/loopback.c:214
 ops_init+0x1d4/0x4a0 net/core/net_namespace.c:138
 setup_net+0x214/0x990 net/core/net_namespace.c:345
 copy_net_ns+0x30f/0x510 net/core/net_namespace.c:486
 create_new_namespaces+0x47a/0x570 kernel/nsproxy.c:103
 copy_namespaces+0x169/0x1b0 kernel/nsproxy.c:161
 copy_process+0x12da/0x3230 kernel/fork.c:2055
 _do_fork+0x197/0x900 kernel/fork.c:2399
 __do_sys_clone kernel/fork.c:2557 [inline]
 __se_sys_clone kernel/fork.c:2538 [inline]
 __x64_sys_clone+0x26b/0x2c0 kernel/fork.c:2538
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

The buggy address belongs to the object at ffff8881d9d8b000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 456 bytes inside of
 512-byte region [ffff8881d9d8b000, ffff8881d9d8b200)
The buggy address belongs to the page:
page:ffffea0007676200 refcount:1 mapcount:0 mapping:ffff8881f5c02500 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5c02500
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL)
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook mm/page_alloc.c:2165 [inline]
 prep_new_page+0x18f/0x370 mm/page_alloc.c:2171
 get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794
 __alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4891
 alloc_slab_page+0x39/0x3c0 mm/slub.c:343
 allocate_slab mm/slub.c:1683 [inline]
 new_slab+0x97/0x440 mm/slub.c:1749
 new_slab_objects mm/slub.c:2505 [inline]
 ___slab_alloc+0x2fe/0x490 mm/slub.c:2667
 __slab_alloc+0x62/0xa0 mm/slub.c:2707
 slab_alloc_node mm/slub.c:2792 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 __kmalloc_track_caller+0x16d/0x2b0 mm/slub.c:4449
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0xb4/0x4d0 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1080 [inline]
 alloc_uevent_skb+0x74/0x220 lib/kobject_uevent.c:290
 uevent_net_broadcast_tagged lib/kobject_uevent.c:351 [inline]
 kobject_uevent_net_broadcast+0x176/0x560 lib/kobject_uevent.c:412
 kobject_uevent_env+0x54d/0x710 lib/kobject_uevent.c:593
 rx_queue_add_kobject net/core/net-sysfs.c:988 [inline]
 net_rx_queue_update_kobjects+0x1c2/0x420 net/core/net-sysfs.c:1010
 register_queue_kobjects net/core/net-sysfs.c:1632 [inline]
 netdev_register_kobject+0x222/0x310 net/core/net-sysfs.c:1858
 register_netdevice+0xbc5/0x12a0 net/core/dev.c:9182
 register_netdev+0x37/0x50 net/core/dev.c:9311
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_pcp_prepare mm/page_alloc.c:1233 [inline]
 free_unref_page_prepare+0x297/0x380 mm/page_alloc.c:3085
 free_unref_page_list+0x10a/0x590 mm/page_alloc.c:3154
 release_pages+0xad8/0xb20 mm/swap.c:842
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:189 [inline]
 tlb_flush_mmu mm/mmu_gather.c:196 [inline]
 tlb_finish_mmu+0x177/0x320 mm/mmu_gather.c:277
 exit_mmap+0x2dc/0x520 mm/mmap.c:3188
 __mmput+0x8e/0x2c0 kernel/fork.c:1101
 exit_mm kernel/exit.c:536 [inline]
 do_exit+0xc08/0x2bc0 kernel/exit.c:846
 do_group_exit+0x138/0x300 kernel/exit.c:982
 get_signal+0xdb1/0x1440 kernel/signal.c:2735
 do_signal+0xb0/0x11f0 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0xc0/0x1a0 arch/x86/entry/common.c:159
 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Memory state around the buggy address:
 ffff8881d9d8b080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881d9d8b100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881d9d8b180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff8881d9d8b200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881d9d8b280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 1be051067 P4D 1be051067 PUD 1edbd9067 PMD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 12457 Comm: syz-executor.1 Tainted: G    B             5.4.265-syzkaller-00001-g1b3143b9b166 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6f09d18 EFLAGS: 00010202
RAX: ffffffff8154e38a RBX: 0000000000000101 RCX: ffff8881dddc6e40
RDX: 0000000000000101 RSI: 0000000000000000 RDI: ffff8881d9d8b1c0
RBP: ffff8881f6f09ec8 R08: ffffffff8154dfce R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 000000010002aa10
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881d9d8b1c0
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001b1c72000 CR4: 00000000003406a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 call_timer_fn+0x36/0x390 kernel/time/timer.c:1418
 expire_timers kernel/time/timer.c:1463 [inline]
 __run_timers+0x879/0xbe0 kernel/time/timer.c:1787
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1800
 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x195/0x1c0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:538 [inline]
 smp_apic_timer_interrupt+0x11a/0x460 arch/x86/kernel/apic/apic.c:1149
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834
 </IRQ>
Modules linked in:
CR2: 0000000000000000
---[ end trace f1bf088ba85328f3 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6f09d18 EFLAGS: 00010202
RAX: ffffffff8154e38a RBX: 0000000000000101 RCX: ffff8881dddc6e40
RDX: 0000000000000101 RSI: 0000000000000000 RDI: ffff8881d9d8b1c0
RBP: ffff8881f6f09ec8 R08: ffffffff8154dfce R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 000000010002aa10
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881d9d8b1c0
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001b1c72000 CR4: 00000000003406a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600