==================================================================
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:1482 [inline]
BUG: KASAN: use-after-free in __run_timers+0x7be/0xbe0 kernel/time/timer.c:1817
Write of size 8 at addr ffff8881ec5331c8 by task kworker/u4:0/7

CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 5.4.290-syzkaller-00017-g6b07fcd94a6a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: netns cleanup_net
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:1482 [inline]
 __run_timers+0x7be/0xbe0 kernel/time/timer.c:1817
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1830
 __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:539 [inline]
 smp_apic_timer_interrupt+0x11a/0x490 arch/x86/kernel/apic/apic.c:1161
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834
 </IRQ>
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x0/0x70 kernel/kcov.c:275
Code: 28 4c 39 d0 77 cf 89 f8 89 f6 48 c7 44 0a 08 03 00 00 00 48 89 44 0a 10 48 89 74 0a 18 4c 89 44 0a 20 49 ff c1 4c 89 09 c3 90 <4c> 8b 04 24 65 48 8b 05 84 3f 9e 7e 65 8b 0d 89 3f 9e 7e f7 c1 00
RSP: 0018:ffff8881f5db7b18 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffffffff85e0d1e0 RCX: ffff8881f5d66e40
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff8881f5db7bd0 R08: ffffffff839d2ab1 R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: ffffffff84fa5580
R13: 1ffff1103ebb6f68 R14: 0000000080000001 R15: ffffffff84a76740
 check_preemption_disabled+0x91/0x320 lib/smp_processor_id.c:16
 __local_bh_enable_ip+0x38/0x70 kernel/softirq.c:184
 get_next_corpse net/netfilter/nf_conntrack_core.c:2069 [inline]
 nf_ct_iterate_cleanup+0x282/0x310 net/netfilter/nf_conntrack_core.c:2092
 nf_conntrack_cleanup_net_list+0x6c/0x200 net/netfilter/nf_conntrack_core.c:2279
 ops_exit_list net/core/net_namespace.c:187 [inline]
 cleanup_net+0x6e2/0xc90 net/core/net_namespace.c:612
 process_one_work+0x765/0xd20 kernel/workqueue.c:2290
 worker_thread+0xaef/0x1470 kernel/workqueue.c:2436
 kthread+0x2da/0x360 kernel/kthread.c:288
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354

Allocated by task 164:
 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]
 kmem_cache_alloc+0xd9/0x250 mm/slub.c:2842
 getname_flags+0xb8/0x4e0 fs/namei.c:141
 do_sys_open+0x357/0x810 fs/open.c:1117
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Freed by task 164:
 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]
 kmem_cache_free+0x10b/0x2c0 mm/slub.c:3096
 do_sys_open+0x65e/0x810 fs/open.c:1132
 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 ffff8881ec532200
 which belongs to the cache names_cache of size 4096
The buggy address is located 4040 bytes inside of
 4096-byte region [ffff8881ec532200, ffff8881ec533200)
The buggy address belongs to the page:
page:ffffea0007b14c00 refcount:1 mapcount:0 mapping:ffff8881f5cfcc80 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5cfcc80
raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, 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:4893
 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]
 kmem_cache_alloc+0x109/0x250 mm/slub.c:2842
 getname_flags+0xb8/0x4e0 fs/namei.c:141
 user_path_at_empty+0x28/0x50 fs/namei.c:2703
 user_path_at include/linux/namei.h:49 [inline]
 vfs_statx+0x115/0x210 fs/stat.c:187
 vfs_fstatat include/linux/fs.h:3387 [inline]
 __do_sys_newfstatat fs/stat.c:367 [inline]
 __se_sys_newfstatat+0xce/0x770 fs/stat.c:361
 do_syscall_64+0xca/0x1c0 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_pcp_prepare mm/page_alloc.c:1233 [inline]
 free_unref_page_prepare+0x297/0x380 mm/page_alloc.c:3085
 free_unref_page mm/page_alloc.c:3134 [inline]
 free_the_page mm/page_alloc.c:4953 [inline]
 __free_pages+0xaf/0x140 mm/page_alloc.c:4961
 pcpu_free_pages mm/percpu-vm.c:64 [inline]
 pcpu_depopulate_chunk mm/percpu-vm.c:328 [inline]
 pcpu_balance_workfn+0x940/0x1450 mm/percpu.c:1865
 process_one_work+0x765/0xd20 kernel/workqueue.c:2290
 worker_thread+0xaef/0x1470 kernel/workqueue.c:2436
 kthread+0x2da/0x360 kernel/kthread.c:288
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354

Memory state around the buggy address:
 ffff8881ec533080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881ec533100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881ec533180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff8881ec533200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881ec533280: 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 1eb951067 P4D 1eb951067 PUD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 7 Comm: kworker/u4:0 Tainted: G    B             5.4.290-syzkaller-00017-g6b07fcd94a6a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: netns cleanup_net
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09d18 EFLAGS: 00010202
RAX: ffffffff8154e8ca RBX: 0000000000000101 RCX: ffff8881f5d66e40
RDX: 0000000000000101 RSI: 0000000000000000 RDI: ffff8881ec5331c0
RBP: ffff8881f6e09ec8 R08: ffffffff8154e50e R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffffa508
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881ec5331c0
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001d8054000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 call_timer_fn+0x36/0x390 kernel/time/timer.c:1448
 expire_timers kernel/time/timer.c:1493 [inline]
 __run_timers+0x879/0xbe0 kernel/time/timer.c:1817
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1830
 __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:539 [inline]
 smp_apic_timer_interrupt+0x11a/0x490 arch/x86/kernel/apic/apic.c:1161
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834
 </IRQ>
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x0/0x70 kernel/kcov.c:275
Code: 28 4c 39 d0 77 cf 89 f8 89 f6 48 c7 44 0a 08 03 00 00 00 48 89 44 0a 10 48 89 74 0a 18 4c 89 44 0a 20 49 ff c1 4c 89 09 c3 90 <4c> 8b 04 24 65 48 8b 05 84 3f 9e 7e 65 8b 0d 89 3f 9e 7e f7 c1 00
RSP: 0018:ffff8881f5db7b18 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffffffff85e0d1e0 RCX: ffff8881f5d66e40
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff8881f5db7bd0 R08: ffffffff839d2ab1 R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: ffffffff84fa5580
R13: 1ffff1103ebb6f68 R14: 0000000080000001 R15: ffffffff84a76740
 check_preemption_disabled+0x91/0x320 lib/smp_processor_id.c:16
 __local_bh_enable_ip+0x38/0x70 kernel/softirq.c:184
 get_next_corpse net/netfilter/nf_conntrack_core.c:2069 [inline]
 nf_ct_iterate_cleanup+0x282/0x310 net/netfilter/nf_conntrack_core.c:2092
 nf_conntrack_cleanup_net_list+0x6c/0x200 net/netfilter/nf_conntrack_core.c:2279
 ops_exit_list net/core/net_namespace.c:187 [inline]
 cleanup_net+0x6e2/0xc90 net/core/net_namespace.c:612
 process_one_work+0x765/0xd20 kernel/workqueue.c:2290
 worker_thread+0xaef/0x1470 kernel/workqueue.c:2436
 kthread+0x2da/0x360 kernel/kthread.c:288
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354
Modules linked in:
CR2: 0000000000000000
---[ end trace 83f4d922ebbc84f9 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09d18 EFLAGS: 00010202
RAX: ffffffff8154e8ca RBX: 0000000000000101 RCX: ffff8881f5d66e40
RDX: 0000000000000101 RSI: 0000000000000000 RDI: ffff8881ec5331c0
RBP: ffff8881f6e09ec8 R08: ffffffff8154e50e R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffffa508
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881ec5331c0
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001d8054000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
----------------
Code disassembly (best guess):
   0:	28 4c 39 d0          	sub    %cl,-0x30(%rcx,%rdi,1)
   4:	77 cf                	ja     0xffffffd5
   6:	89 f8                	mov    %edi,%eax
   8:	89 f6                	mov    %esi,%esi
   a:	48 c7 44 0a 08 03 00 	movq   $0x3,0x8(%rdx,%rcx,1)
  11:	00 00
  13:	48 89 44 0a 10       	mov    %rax,0x10(%rdx,%rcx,1)
  18:	48 89 74 0a 18       	mov    %rsi,0x18(%rdx,%rcx,1)
  1d:	4c 89 44 0a 20       	mov    %r8,0x20(%rdx,%rcx,1)
  22:	49 ff c1             	inc    %r9
  25:	4c 89 09             	mov    %r9,(%rcx)
  28:	c3                   	ret
  29:	90                   	nop
* 2a:	4c 8b 04 24          	mov    (%rsp),%r8 <-- trapping instruction
  2e:	65 48 8b 05 84 3f 9e 	mov    %gs:0x7e9e3f84(%rip),%rax        # 0x7e9e3fba
  35:	7e
  36:	65 8b 0d 89 3f 9e 7e 	mov    %gs:0x7e9e3f89(%rip),%ecx        # 0x7e9e3fc6
  3d:	f7                   	.byte 0xf7
  3e:	c1                   	.byte 0xc1