==================================================================
BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:814 [inline]
BUG: KASAN: use-after-free in enqueue_timer+0xb7/0x300 kernel/time/timer.c:541
Write of size 8 at addr ffff8881d4d2f1c8 by task syz.3.558/2426

CPU: 0 PID: 2426 Comm: syz.3.558 Not tainted 5.4.290-syzkaller-00017-g6b07fcd94a6a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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_add_head include/linux/list.h:814 [inline]
 enqueue_timer+0xb7/0x300 kernel/time/timer.c:541
 __internal_add_timer kernel/time/timer.c:554 [inline]
 internal_add_timer+0x240/0x430 kernel/time/timer.c:604
 __mod_timer+0x6f1/0x13e0 kernel/time/timer.c:1065
 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:unwind_next_frame+0x1870/0x1ea0 arch/x86/kernel/unwind_orc.c:613
Code: 88 00 00 00 4c 8b 34 24 0f 85 a0 01 00 00 41 c7 06 00 00 00 00 31 c0 48 c7 84 24 a0 00 00 00 0e 36 e0 45 48 c7 03 00 00 00 00 <48> c7 43 09 00 00 00 00 48 c7 43 11 00 00 00 00 48 c7 43 19 00 00
RSP: 0018:ffff8881eddae7e0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 0000000080000001 RBX: ffffed103dbb5d10 RCX: 0000000080000000
RDX: ffff8881eddaec20 RSI: ffff8881eddae760 RDI: 0000000000000001
RBP: ffff8881eddaead0 R08: dffffc0000000000 R09: ffff8881eddaec30
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff0cf99b8
R13: ffffffff867ccdc5 R14: ffff8881eddaebe0 R15: ffff8881edda8000
 __unwind_start+0x708/0x890 arch/x86/kernel/unwind_orc.c:691
 unwind_start arch/x86/include/asm/unwind.h:60 [inline]
 arch_stack_walk+0xdd/0x140 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x118/0x1c0 kernel/stacktrace.c:123
 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_trace+0xdc/0x260 mm/slub.c:2854
 kmalloc include/linux/slab.h:556 [inline]
 kzalloc include/linux/slab.h:690 [inline]
 copy_verifier_state+0x581/0xbf0 kernel/bpf/verifier.c:746
 is_state_visited kernel/bpf/verifier.c:7702 [inline]
 do_check+0x3286/0x9820 kernel/bpf/verifier.c:7837
 bpf_check+0x2183/0xb3e0 kernel/bpf/verifier.c:9637
 bpf_prog_load kernel/bpf/syscall.c:1724 [inline]
 __do_sys_bpf kernel/bpf/syscall.c:2891 [inline]
 __se_sys_bpf+0x8139/0xbcb0 kernel/bpf/syscall.c:2849
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7ff7e0f6b169
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:00007ff7df5d5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007ff7e1183fa0 RCX: 00007ff7e0f6b169
RDX: 0000000000000090 RSI: 0000400000002c40 RDI: 0000000000000005
RBP: 00007ff7e0fec2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ff7e1183fa0 R15: 00007ffe865e7438

Allocated by task 2351:
 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]
 pskb_expand_head+0x10c/0x10b0 net/core/skbuff.c:1653
 __bpf_try_make_writable net/core/filter.c:1635 [inline]
 bpf_try_make_writable net/core/filter.c:1641 [inline]
 bpf_try_make_head_writable net/core/filter.c:1649 [inline]
 ____bpf_clone_redirect net/core/filter.c:2145 [inline]
 bpf_clone_redirect+0x110/0x350 net/core/filter.c:2123
 0xffffffffa00989dd
 bpf_call_func include/linux/filter.h:627 [inline]
 bpf_test_run+0x2ae/0x6c0 net/bpf/test_run.c:44
 bpf_prog_test_run_skb+0x73c/0xf00 net/bpf/test_run.c:311
 bpf_prog_test_run kernel/bpf/syscall.c:2124 [inline]
 __do_sys_bpf kernel/bpf/syscall.c:2909 [inline]
 __se_sys_bpf+0x2e37/0xbcb0 kernel/bpf/syscall.c:2849
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Freed by task 2351:
 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]
 kfree_skb+0xb8/0x3c0 net/core/skbuff.c:708
 llc_rcv+0x68c/0xb50 net/llc/llc_input.c:139
 __netif_receive_skb_one_core net/core/dev.c:4991 [inline]
 __netif_receive_skb+0x1c6/0x530 net/core/dev.c:5105
 process_backlog+0x34f/0x680 net/core/dev.c:5940
 napi_poll net/core/dev.c:6386 [inline]
 net_rx_action+0x53f/0x1160 net/core/dev.c:6454
 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292

The buggy address belongs to the object at ffff8881d4d2f000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 456 bytes inside of
 512-byte region [ffff8881d4d2f000, ffff8881d4d2f200)
The buggy address belongs to the page:
page:ffffea0007534b00 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 0x1d2a20(GFP_ATOMIC|__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]
 __kmalloc_track_caller+0x16d/0x2b0 mm/slub.c:4449
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 pskb_expand_head+0x10c/0x10b0 net/core/skbuff.c:1653
 __bpf_try_make_writable net/core/filter.c:1635 [inline]
 bpf_try_make_writable net/core/filter.c:1641 [inline]
 bpf_try_make_head_writable net/core/filter.c:1649 [inline]
 ____bpf_clone_redirect net/core/filter.c:2145 [inline]
 bpf_clone_redirect+0x110/0x350 net/core/filter.c:2123
 0xffffffffa00989dd
 bpf_call_func include/linux/filter.h:627 [inline]
 bpf_test_run+0x2ae/0x6c0 net/bpf/test_run.c:44
 bpf_prog_test_run_skb+0x73c/0xf00 net/bpf/test_run.c:311
 bpf_prog_test_run kernel/bpf/syscall.c:2124 [inline]
 __do_sys_bpf kernel/bpf/syscall.c:2909 [inline]
 __se_sys_bpf+0x2e37/0xbcb0 kernel/bpf/syscall.c:2849
 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_pages_ok+0x847/0x950 mm/page_alloc.c:1438
 free_the_page mm/page_alloc.c:4955 [inline]
 __free_pages+0x91/0x140 mm/page_alloc.c:4961
 device_release+0x6b/0x190 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+0x1e6/0x2f0 lib/kobject.c:764
 tun_set_iff+0x870/0xdc0 drivers/net/tun.c:2924
 __tun_chr_ioctl+0x8a9/0x1d00 drivers/net/tun.c:3187
 do_vfs_ioctl+0x742/0x1720 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+0xd4/0x110 fs/ioctl.c:747
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Memory state around the buggy address:
 ffff8881d4d2f080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881d4d2f100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881d4d2f180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff8881d4d2f200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881d4d2f280: 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 1eb9bf067 P4D 1eb9bf067 PUD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 2426 Comm: syz.3.558 Tainted: G    B             5.4.290-syzkaller-00017-g6b07fcd94a6a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09d18 EFLAGS: 00010206
RAX: ffffffff8154e8ca RBX: 0000000000000100 RCX: ffff8881d5c72f40
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881d4d2f1c0
RBP: ffff8881f6e09ec8 R08: ffffffff8154e50e R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffffa888
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881d4d2f1c0
FS:  00007ff7df5d56c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001ef2e2000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000400000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000010602
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:unwind_next_frame+0x1870/0x1ea0 arch/x86/kernel/unwind_orc.c:613
Code: 88 00 00 00 4c 8b 34 24 0f 85 a0 01 00 00 41 c7 06 00 00 00 00 31 c0 48 c7 84 24 a0 00 00 00 0e 36 e0 45 48 c7 03 00 00 00 00 <48> c7 43 09 00 00 00 00 48 c7 43 11 00 00 00 00 48 c7 43 19 00 00
RSP: 0018:ffff8881eddae7e0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 0000000080000001 RBX: ffffed103dbb5d10 RCX: 0000000080000000
RDX: ffff8881eddaec20 RSI: ffff8881eddae760 RDI: 0000000000000001
RBP: ffff8881eddaead0 R08: dffffc0000000000 R09: ffff8881eddaec30
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff0cf99b8
R13: ffffffff867ccdc5 R14: ffff8881eddaebe0 R15: ffff8881edda8000
 __unwind_start+0x708/0x890 arch/x86/kernel/unwind_orc.c:691
 unwind_start arch/x86/include/asm/unwind.h:60 [inline]
 arch_stack_walk+0xdd/0x140 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x118/0x1c0 kernel/stacktrace.c:123
 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_trace+0xdc/0x260 mm/slub.c:2854
 kmalloc include/linux/slab.h:556 [inline]
 kzalloc include/linux/slab.h:690 [inline]
 copy_verifier_state+0x581/0xbf0 kernel/bpf/verifier.c:746
 is_state_visited kernel/bpf/verifier.c:7702 [inline]
 do_check+0x3286/0x9820 kernel/bpf/verifier.c:7837
 bpf_check+0x2183/0xb3e0 kernel/bpf/verifier.c:9637
 bpf_prog_load kernel/bpf/syscall.c:1724 [inline]
 __do_sys_bpf kernel/bpf/syscall.c:2891 [inline]
 __se_sys_bpf+0x8139/0xbcb0 kernel/bpf/syscall.c:2849
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7ff7e0f6b169
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:00007ff7df5d5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007ff7e1183fa0 RCX: 00007ff7e0f6b169
RDX: 0000000000000090 RSI: 0000400000002c40 RDI: 0000000000000005
RBP: 00007ff7e0fec2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ff7e1183fa0 R15: 00007ffe865e7438
Modules linked in:
CR2: 0000000000000000
---[ end trace 07d7e426d7d9b6a9 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09d18 EFLAGS: 00010206
RAX: ffffffff8154e8ca RBX: 0000000000000100 RCX: ffff8881d5c72f40
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881d4d2f1c0
RBP: ffff8881f6e09ec8 R08: ffffffff8154e50e R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffffa888
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881d4d2f1c0
FS:  00007ff7df5d56c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001ef2e2000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000400000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000010602
----------------
Code disassembly (best guess):
   0:	88 00                	mov    %al,(%rax)
   2:	00 00                	add    %al,(%rax)
   4:	4c 8b 34 24          	mov    (%rsp),%r14
   8:	0f 85 a0 01 00 00    	jne    0x1ae
   e:	41 c7 06 00 00 00 00 	movl   $0x0,(%r14)
  15:	31 c0                	xor    %eax,%eax
  17:	48 c7 84 24 a0 00 00 	movq   $0x45e0360e,0xa0(%rsp)
  1e:	00 0e 36 e0 45
  23:	48 c7 03 00 00 00 00 	movq   $0x0,(%rbx)
* 2a:	48 c7 43 09 00 00 00 	movq   $0x0,0x9(%rbx) <-- trapping instruction
  31:	00
  32:	48 c7 43 11 00 00 00 	movq   $0x0,0x11(%rbx)
  39:	00
  3a:	48                   	rex.W
  3b:	c7                   	.byte 0xc7
  3c:	43 19 00             	rex.XB sbb %eax,(%r8)