==================================================================
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+0x759/0xb60 kernel/time/timer.c:1817
Write of size 8 at addr ffff8881e37bb1c8 by task syz.4.809/2790

CPU: 0 PID: 2790 Comm: syz.4.809 Not tainted 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <IRQ>
 __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
 __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+0x759/0xb60 kernel/time/timer.c:1817
 run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1830
 __do_softirq+0x236/0x660 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x197/0x1c0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:539 [inline]
 smp_apic_timer_interrupt+0x11d/0x490 arch/x86/kernel/apic/apic.c:1161
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834
 </IRQ>
RIP: 0010:kmalloc_slab+0x0/0xb0 mm/slab_common.c:1163
Code: c7 58 57 d6 85 e8 40 6b a8 02 e8 1b 2c b6 ff 5b 41 5c 41 5e 41 5f 5d c3 66 90 55 48 89 e5 83 3d 8d f9 d4 04 03 0f 93 c0 5d c3 <55> 48 89 e5 41 56 53 50 89 f3 48 81 ff c0 00 00 00 77 18 48 85 ff
RSP: 0018:ffff8881e2ba7690 EFLAGS: 00000287 ORIG_RAX: ffffffffffffff13
RAX: ffffffff81804654 RBX: 0000000000100dc0 RCX: 0000000000000002
RDX: ffff8881e7aa8000 RSI: 0000000000100dc0 RDI: 0000000000000018
RBP: ffff8881e2ba76d8 R08: ffff8881e7aa8000 R09: 0000000000000002
R10: 0000000000000003 R11: 0000000000000002 R12: 0000000000100dc0
R13: 0000000000000000 R14: 0000000000100dc0 R15: 0000000000000018
 __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]
 kvmalloc_array include/linux/mm.h:779 [inline]
 kvcalloc include/linux/mm.h:784 [inline]
 bpf_check+0x17f9/0x9cf0 kernel/bpf/verifier.c:9618
 bpf_prog_load+0xa5f/0xe10 kernel/bpf/syscall.c:1724
 __do_sys_bpf kernel/bpf/syscall.c:2891 [inline]
 __se_sys_bpf+0x435/0x570 kernel/bpf/syscall.c:2849
 __x64_sys_bpf+0x7b/0x90 kernel/bpf/syscall.c:2849
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f48790d6969
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:00007f487773f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f48792fdfa0 RCX: 00007f48790d6969
RDX: 0000000000000080 RSI: 0000200000000600 RDI: 0000000000000005
RBP: 00007f4879158ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f48792fdfa0 R15: 00007ffe4e0bdf58

Allocated by task 343:
 save_stack mm/kasan/common.c:70 [inline]
 set_track mm/kasan/common.c:78 [inline]
 __kasan_kmalloc+0x162/0x200 mm/kasan/common.c:529
 kasan_slab_alloc+0x12/0x20 mm/kasan/common.c:537
 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+0xe2/0x270 mm/slub.c:2842
 dup_fd+0x70/0xaf0 fs/file.c:276
 copy_files+0xc4/0x160 kernel/fork.c:1485
 copy_process+0x10b5/0x2cf0 kernel/fork.c:2040
 _do_fork+0x190/0x860 kernel/fork.c:2399
 __do_sys_clone kernel/fork.c:2557 [inline]
 __se_sys_clone kernel/fork.c:2538 [inline]
 __x64_sys_clone+0x12e/0x160 kernel/fork.c:2538
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Freed by task 2713:
 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+0x1c3/0x280 mm/kasan/common.c:487
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:496
 slab_free_hook mm/slub.c:1455 [inline]
 slab_free_freelist_hook+0xb7/0x180 mm/slub.c:1494
 slab_free mm/slub.c:3080 [inline]
 kmem_cache_free+0x10c/0x2c0 mm/slub.c:3096
 put_files_struct+0x2f9/0x330 fs/file.c:417
 exit_files+0x80/0xa0 fs/file.c:441
 do_exit+0xa0c/0x2660 kernel/exit.c:856
 do_group_exit+0x13e/0x300 kernel/exit.c:984
 get_signal+0xdee/0x13d0 kernel/signal.c:2738
 do_signal+0xad/0xda0 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0xc4/0x1b0 arch/x86/entry/common.c:159
 prepare_exit_to_usermode+0x18e/0x1f0 arch/x86/entry/common.c:194
 syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
 do_syscall_64+0x13e/0x170 arch/x86/entry/common.c:300
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

The buggy address belongs to the object at ffff8881e37bb0c0
 which belongs to the cache files_cache of size 704
The buggy address is located 264 bytes inside of
 704-byte region [ffff8881e37bb0c0, ffff8881e37bb380)
The buggy address belongs to the page:
page:ffffea00078dee00 refcount:1 mapcount:0 mapping:ffff8881f5cf7400 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5cf7400
raw: 0000000000000000 0000000080130013 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+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_slab_page+0x3c/0x3b0 mm/slub.c:343
 allocate_slab mm/slub.c:1683 [inline]
 new_slab+0x93/0x420 mm/slub.c:1749
 new_slab_objects mm/slub.c:2505 [inline]
 ___slab_alloc+0x29e/0x420 mm/slub.c:2667
 __slab_alloc+0x63/0xa0 mm/slub.c:2707
 slab_alloc_node mm/slub.c:2792 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0x12c/0x270 mm/slub.c:2842
 dup_fd+0x70/0xaf0 fs/file.c:276
 copy_files+0xc4/0x160 kernel/fork.c:1485
 copy_process+0x10b5/0x2cf0 kernel/fork.c:2040
 _do_fork+0x190/0x860 kernel/fork.c:2399
 __do_sys_clone kernel/fork.c:2557 [inline]
 __se_sys_clone kernel/fork.c:2538 [inline]
 __x64_sys_clone+0x12e/0x160 kernel/fork.c:2538
 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
 netdev_run_todo+0xae4/0xc70 net/core/dev.c:9488
 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:112
 tun_detach drivers/net/tun.c:766 [inline]
 tun_chr_close+0xc4/0x140 drivers/net/tun.c:3563
 __fput+0x2a3/0x730 fs/file_table.c:281
 ____fput+0x15/0x20 fs/file_table.c:314
 task_work_run+0x146/0x170 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xa43/0x2660 kernel/exit.c:861
 do_group_exit+0x13e/0x300 kernel/exit.c:984

Memory state around the buggy address:
 ffff8881e37bb080: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8881e37bb100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881e37bb180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff8881e37bb200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881e37bb280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 1e159f067 P4D 1e159f067 PUD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 2790 Comm: syz.4.809 Tainted: G    B             5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09cf0 EFLAGS: 00010206
RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881e7aa8000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881e37bb1c0
RBP: ffff8881f6e09d30 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103edc1398 R11: 1ffff1103edc1398 R12: 00000000ffffb638
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e37bb1c0
FS:  00007f487773f6c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001e3e21000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 call_timer_fn+0x3c/0x380 kernel/time/timer.c:1448
 expire_timers kernel/time/timer.c:1493 [inline]
 __run_timers+0x81d/0xb60 kernel/time/timer.c:1817
 run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1830
 __do_softirq+0x236/0x660 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x197/0x1c0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:539 [inline]
 smp_apic_timer_interrupt+0x11d/0x490 arch/x86/kernel/apic/apic.c:1161
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834
 </IRQ>
RIP: 0010:kmalloc_slab+0x0/0xb0 mm/slab_common.c:1163
Code: c7 58 57 d6 85 e8 40 6b a8 02 e8 1b 2c b6 ff 5b 41 5c 41 5e 41 5f 5d c3 66 90 55 48 89 e5 83 3d 8d f9 d4 04 03 0f 93 c0 5d c3 <55> 48 89 e5 41 56 53 50 89 f3 48 81 ff c0 00 00 00 77 18 48 85 ff
RSP: 0018:ffff8881e2ba7690 EFLAGS: 00000287 ORIG_RAX: ffffffffffffff13
RAX: ffffffff81804654 RBX: 0000000000100dc0 RCX: 0000000000000002
RDX: ffff8881e7aa8000 RSI: 0000000000100dc0 RDI: 0000000000000018
RBP: ffff8881e2ba76d8 R08: ffff8881e7aa8000 R09: 0000000000000002
R10: 0000000000000003 R11: 0000000000000002 R12: 0000000000100dc0
R13: 0000000000000000 R14: 0000000000100dc0 R15: 0000000000000018
 __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]
 kvmalloc_array include/linux/mm.h:779 [inline]
 kvcalloc include/linux/mm.h:784 [inline]
 bpf_check+0x17f9/0x9cf0 kernel/bpf/verifier.c:9618
 bpf_prog_load+0xa5f/0xe10 kernel/bpf/syscall.c:1724
 __do_sys_bpf kernel/bpf/syscall.c:2891 [inline]
 __se_sys_bpf+0x435/0x570 kernel/bpf/syscall.c:2849
 __x64_sys_bpf+0x7b/0x90 kernel/bpf/syscall.c:2849
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f48790d6969
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:00007f487773f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f48792fdfa0 RCX: 00007f48790d6969
RDX: 0000000000000080 RSI: 0000200000000600 RDI: 0000000000000005
RBP: 00007f4879158ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f48792fdfa0 R15: 00007ffe4e0bdf58
Modules linked in:
CR2: 0000000000000000
---[ end trace 528667a61879d105 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09cf0 EFLAGS: 00010206
RAX: ffffffff8150a590 RBX: 0000000000000100 RCX: ffff8881e7aa8000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881e37bb1c0
RBP: ffff8881f6e09d30 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103edc1398 R11: 1ffff1103edc1398 R12: 00000000ffffb638
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881e37bb1c0
FS:  00007f487773f6c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001e3e21000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
----------------
Code disassembly (best guess), 4 bytes skipped:
   0:	85 e8                	test   %ebp,%eax
   2:	40 6b a8 02 e8 1b 2c 	rex imul $0xffffffb6,0x2c1be802(%rax),%ebp
   9:	b6
   a:	ff 5b 41             	lcall  *0x41(%rbx)
   d:	5c                   	pop    %rsp
   e:	41 5e                	pop    %r14
  10:	41 5f                	pop    %r15
  12:	5d                   	pop    %rbp
  13:	c3                   	ret
  14:	66 90                	xchg   %ax,%ax
  16:	55                   	push   %rbp
  17:	48 89 e5             	mov    %rsp,%rbp
  1a:	83 3d 8d f9 d4 04 03 	cmpl   $0x3,0x4d4f98d(%rip)        # 0x4d4f9ae
  21:	0f 93 c0             	setae  %al
  24:	5d                   	pop    %rbp
  25:	c3                   	ret
* 26:	55                   	push   %rbp <-- trapping instruction
  27:	48 89 e5             	mov    %rsp,%rbp
  2a:	41 56                	push   %r14
  2c:	53                   	push   %rbx
  2d:	50                   	push   %rax
  2e:	89 f3                	mov    %esi,%ebx
  30:	48 81 ff c0 00 00 00 	cmp    $0xc0,%rdi
  37:	77 18                	ja     0x51
  39:	48 85 ff             	test   %rdi,%rdi