==================================================================
BUG: KASAN: slab-out-of-bounds in hlist_add_head include/linux/list.h:814 [inline]
BUG: KASAN: slab-out-of-bounds in enqueue_timer+0x9e/0x2c0 kernel/time/timer.c:541
Write of size 8 at addr ffff8881df3f71c8 by task udevd/1363

CPU: 1 PID: 1363 Comm: udevd 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_add_head include/linux/list.h:814 [inline]
 enqueue_timer+0x9e/0x2c0 kernel/time/timer.c:541
 __internal_add_timer kernel/time/timer.c:554 [inline]
 internal_add_timer+0x208/0x3e0 kernel/time/timer.c:604
 __mod_timer+0x5ab/0x1150 kernel/time/timer.c:1065
 mod_timer+0x1f/0x30 kernel/time/timer.c:1117
 br_hello_timer_expired+0x120/0x180 net/bridge/br_stp_timer.c:40
 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:security_netlink_send+0x0/0xa0 security/security.c:1944
Code: e7 e8 24 50 93 ff 4c 89 ff 48 8b 75 d0 48 8b 55 c8 41 ff 14 24 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d c3 66 0f 1f 44 00 00 <55> 48 89 e5 41 57 41 56 41 55 41 54 53 48 89 f3 49 89 fe 49 bd 00
RSP: 0018:ffff8881e47bf9f8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
RAX: ae03f4f99e32b001 RBX: ffff8881e4083b40 RCX: ae03f4f99e32b000
RDX: ffff8881e8a92f40 RSI: ffff8881e4083b40 RDI: ffff8881e4f1e000
RBP: ffff8881e47bfb10 R08: ffff8881e8a92f40 R09: 0000000000000002
R10: 0000000000000040 R11: 0000000000000000 R12: 1ffff1103c8f7f4c
R13: ffff8881d537c800 R14: ffff8881e47bfe10 R15: 00000000000000cd
 sock_sendmsg_nosec net/socket.c:638 [inline]
 __sock_sendmsg net/socket.c:650 [inline]
 ____sys_sendmsg+0x57b/0x8d0 net/socket.c:2306
 ___sys_sendmsg net/socket.c:2360 [inline]
 __sys_sendmsg+0x28e/0x360 net/socket.c:2406
 __do_sys_sendmsg net/socket.c:2415 [inline]
 __se_sys_sendmsg net/socket.c:2413 [inline]
 __x64_sys_sendmsg+0x7f/0x90 net/socket.c:2413
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f421005ba4b
Code: ff 89 ef 48 89 04 24 e8 22 56 f9 ff 48 8b 04 24 48 83 c4 20 5d c3 c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 6d 48 8b 15 ae c3 0c 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffead5a1e78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000055d64334f090 RCX: 00007f421005ba4b
RDX: 0000000000000000 RSI: 00007ffead5a1e88 RDI: 000000000000000c
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000000a5 R14: 0000000000000000 R15: 000055d6433312c0

Allocated by task 1817:
 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_kmalloc+0xd/0x20 mm/kasan/common.c:543
 __kmalloc+0x12a/0x2f0 mm/slub.c:3913
 kmalloc_array include/linux/slab.h:618 [inline]
 realloc_stack_state kernel/bpf/verifier.c:595 [inline]
 realloc_func_state+0x305/0x5b0 kernel/bpf/verifier.c:611
 copy_func_state kernel/bpf/verifier.c:704 [inline]
 copy_verifier_state+0x65f/0xc20 kernel/bpf/verifier.c:751
 push_stack+0x156/0x480 kernel/bpf/verifier.c:819
 check_cond_jmp_op+0x5c3/0x17f0 kernel/bpf/verifier.c:6192
 do_check+0x5058/0x8a60 kernel/bpf/verifier.c:8109
 bpf_check+0x208a/0x9cf0 kernel/bpf/verifier.c:9637
 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

Freed by task 1817:
 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]
 kfree+0xbe/0x260 mm/slub.c:4071
 free_func_state kernel/bpf/verifier.c:671 [inline]
 free_verifier_state+0xd6/0x220 kernel/bpf/verifier.c:688
 pop_stack kernel/bpf/verifier.c:795 [inline]
 do_check+0x65d1/0x8a60 kernel/bpf/verifier.c:8098
 bpf_check+0x208a/0x9cf0 kernel/bpf/verifier.c:9637
 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

The buggy address belongs to the object at ffff8881df3f7000
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 200 bytes to the right of
 256-byte region [ffff8881df3f7000, ffff8881df3f7100)
The buggy address belongs to the page:
page:ffffea00077cfd80 refcount:1 mapcount:0 mapping:ffff8881f5c02780 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5c02780
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, 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]
 __kmalloc+0x176/0x2f0 mm/slub.c:3909
 kmalloc_array include/linux/slab.h:618 [inline]
 realloc_stack_state kernel/bpf/verifier.c:595 [inline]
 realloc_func_state+0x305/0x5b0 kernel/bpf/verifier.c:611
 copy_func_state kernel/bpf/verifier.c:704 [inline]
 copy_verifier_state+0x65f/0xc20 kernel/bpf/verifier.c:751
 push_stack+0x156/0x480 kernel/bpf/verifier.c:819
 check_cond_jmp_op+0x5c3/0x17f0 kernel/bpf/verifier.c:6192
 do_check+0x5058/0x8a60 kernel/bpf/verifier.c:8109
 bpf_check+0x208a/0x9cf0 kernel/bpf/verifier.c:9637
 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
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+0x2a9/0x3a0 mm/page_alloc.c:3085
 free_unref_page mm/page_alloc.c:3134 [inline]
 free_the_page mm/page_alloc.c:4954 [inline]
 __free_pages mm/page_alloc.c:4962 [inline]
 free_pages+0x117/0x180 mm/page_alloc.c:4970
 tlb_batch_list_free mm/mmu_gather.c:61 [inline]
 tlb_finish_mmu+0x248/0x300 mm/mmu_gather.c:280
 exit_mmap+0x2db/0x520 mm/mmap.c:3193
 __mmput+0x92/0x2e0 kernel/fork.c:1101
 mmput+0x47/0x60 kernel/fork.c:1122
 exit_mm kernel/exit.c:538 [inline]
 do_exit+0x99f/0x2660 kernel/exit.c:848
 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
 swapgs_restore_regs_and_return_to_usermode+0x0/0x54

Memory state around the buggy address:
 ffff8881df3f7080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881df3f7100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881df3f7180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                              ^
 ffff8881df3f7200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881df3f7280: 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 0 P4D 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 0 Comm: swapper/1 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:ffff8881f6f09cf0 EFLAGS: 00010202
RAX: ffffffff8150a590 RBX: 0000000000000101 RCX: ffff8881f5dc0000
RDX: 0000000000000101 RSI: 0000000000000000 RDI: ffff8881df3f71c0
RBP: ffff8881f6f09d30 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103ede1398 R11: 1ffff1103ede1398 R12: 0000000100001968
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881df3f71c0
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001de427000 CR4: 00000000003406a0
DR0: 0000200000000300 DR1: 0000200000000300 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:default_idle+0x23/0x40 arch/x86/kernel/process.c:578
Code: 90 90 00 00 90 90 00 55 48 89 e5 e8 87 b2 f5 fd bf 01 00 00 00 89 c6 e8 bb 1c fc fc 0f 1f 44 00 00 0f 00 2d cf c2 59 00 fb f4 <e8> 68 b2 f5 fd bf ff ff ff ff 89 c6 e8 9c 1c fc fc 5d c3 66 2e 0f
RSP: 0018:ffff8881f5df7d80 EFLAGS: 000002c6 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000001 RBX: ffff8881f5dc0000 RCX: ffff8881f5dc0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: ffff8881f5df7d80 R08: dffffc0000000000 R09: ffffed103ebb8001
R10: ffffed103ebb8001 R11: 1ffff1103ebb8000 R12: 0000000000000001
R13: 1ffff1103ebb8000 R14: 0000000000000000 R15: ffffffff862bb528
 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:568
 default_idle_call kernel/sched/idle.c:94 [inline]
 cpuidle_idle_call kernel/sched/idle.c:154 [inline]
 do_idle+0x21d/0x550 kernel/sched/idle.c:264
 cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:356
 start_secondary+0x366/0x420 arch/x86/kernel/smpboot.c:277
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241
Modules linked in:
CR2: 0000000000000000
---[ end trace c8aae2afd88974f3 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6f09cf0 EFLAGS: 00010202
RAX: ffffffff8150a590 RBX: 0000000000000101 RCX: ffff8881f5dc0000
RDX: 0000000000000101 RSI: 0000000000000000 RDI: ffff8881df3f71c0
RBP: ffff8881f6f09d30 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103ede1398 R11: 1ffff1103ede1398 R12: 0000000100001968
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881df3f71c0
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001de427000 CR4: 00000000003406a0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
----------------
Code disassembly (best guess):
   0:	e7 e8                	out    %eax,$0xe8
   2:	24 50                	and    $0x50,%al
   4:	93                   	xchg   %eax,%ebx
   5:	ff 4c 89 ff          	decl   -0x1(%rcx,%rcx,4)
   9:	48 8b 75 d0          	mov    -0x30(%rbp),%rsi
   d:	48 8b 55 c8          	mov    -0x38(%rbp),%rdx
  11:	41 ff 14 24          	call   *(%r12)
  15:	48 83 c4 10          	add    $0x10,%rsp
  19:	5b                   	pop    %rbx
  1a:	41 5c                	pop    %r12
  1c:	41 5d                	pop    %r13
  1e:	41 5e                	pop    %r14
  20:	41 5f                	pop    %r15
  22:	5d                   	pop    %rbp
  23:	c3                   	ret
  24:	66 0f 1f 44 00 00    	nopw   0x0(%rax,%rax,1)
* 2a:	55                   	push   %rbp <-- trapping instruction
  2b:	48 89 e5             	mov    %rsp,%rbp
  2e:	41 57                	push   %r15
  30:	41 56                	push   %r14
  32:	41 55                	push   %r13
  34:	41 54                	push   %r12
  36:	53                   	push   %rbx
  37:	48 89 f3             	mov    %rsi,%rbx
  3a:	49 89 fe             	mov    %rdi,%r14
  3d:	49                   	rex.WB
  3e:	bd                   	.byte 0xbd