==================================================================
BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:814 [inline]
BUG: KASAN: use-after-free in enqueue_timer+0x9e/0x2c0 kernel/time/timer.c:541
Write of size 8 at addr ffff8881eac7b1c8 by task syz.3.963/3788

CPU: 0 PID: 3788 Comm: syz.3.963 Tainted: G        W         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
 can_stat_update+0xbab/0xc40 net/can/proc.c:186
 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:jhash2 include/linux/jhash.h:126 [inline]
RIP: 0010:hash_stack lib/stackdepot.c:156 [inline]
RIP: 0010:stack_depot_save+0x56/0x4c0 lib/stackdepot.c:237
Code: 57 01 00 00 41 89 f7 49 89 fe 43 8d 3c 3f 46 8d 24 fd 7b 71 f5 75 83 ff 04 0f 82 87 00 00 00 45 89 e3 44 89 e1 4c 89 f6 03 0e <44> 03 5e 04 44 03 66 08 45 89 e0 41 c1 c0 04 44 29 e1 41 31 c8 45
RSP: 0018:ffff8881e0b870c0 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffff8881e0b87160 RCX: 00000000a8c5f9e5
RDX: 0000000000102800 RSI: ffff8881e0b871cc RDI: 0000000000000005
RBP: ffff8881e0b87110 R08: 00000000707c41a7 R09: 000000001414d234
R10: 00000000ea802bc8 R11: 0000000035f354dd R12: 00000000385584b0
R13: dffffc0000000000 R14: ffff8881e0b87160 R15: 0000000000000010
 save_stack+0x115/0x560 mm/page_owner.c:135
 __set_page_owner+0x39/0x1e0 mm/page_owner.c:191
 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_pages include/linux/gfp.h:503 [inline]
 __alloc_pages_node include/linux/gfp.h:516 [inline]
 alloc_pages_node include/linux/gfp.h:530 [inline]
 __get_free_pages+0xe/0x30 mm/page_alloc.c:4938
 tlb_next_batch mm/mmu_gather.c:29 [inline]
 __tlb_remove_page_size+0x17b/0x300 mm/mmu_gather.c:83
 __tlb_remove_page include/asm-generic/tlb.h:426 [inline]
 zap_pte_range mm/memory.c:1108 [inline]
 zap_pmd_range mm/memory.c:1222 [inline]
 zap_pud_range mm/memory.c:1251 [inline]
 zap_p4d_range mm/memory.c:1272 [inline]
 unmap_page_range+0xf7c/0x1b20 mm/memory.c:1293
 unmap_single_vma mm/memory.c:1338 [inline]
 unmap_vmas+0x245/0x340 mm/memory.c:1370
 exit_mmap+0x2bb/0x520 mm/mmap.c:3191
 __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
 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
RIP: 0033:0x7f11e8d5a969
Code: Bad RIP value.
RSP: 002b:00007f11e73c3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: fffffffffffffff5 RBX: 00007f11e8f81fa0 RCX: 00007f11e8d5a969
RDX: 0000000000000080 RSI: 0000200000000280 RDI: 0000000000000005
RBP: 00007f11e8ddcab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f11e8f81fa0 R15: 00007ffe98de6f98

Allocated by task 768:
 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
 getname_flags+0xb9/0x500 fs/namei.c:141
 getname fs/namei.c:212 [inline]
 user_path_mountpoint_at+0x28/0x50 fs/namei.c:2842
 ksys_umount+0x147/0x360 fs/namespace.c:1690
 __do_sys_umount fs/namespace.c:1716 [inline]
 __se_sys_umount fs/namespace.c:1714 [inline]
 __x64_sys_umount+0x5a/0x70 fs/namespace.c:1714
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Freed by task 768:
 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
 putname fs/namei.c:262 [inline]
 filename_mountpoint+0x43f/0x5c0 fs/namei.c:2820
 user_path_mountpoint_at+0x39/0x50 fs/namei.c:2842
 ksys_umount+0x147/0x360 fs/namespace.c:1690
 __do_sys_umount fs/namespace.c:1716 [inline]
 __se_sys_umount fs/namespace.c:1714 [inline]
 __x64_sys_umount+0x5a/0x70 fs/namespace.c:1714
 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 ffff8881eac7a200
 which belongs to the cache names_cache of size 4096
The buggy address is located 4040 bytes inside of
 4096-byte region [ffff8881eac7a200, ffff8881eac7b200)
The buggy address belongs to the page:
page:ffffea0007ab1e00 refcount:1 mapcount:0 mapping:ffff8881f5d00c80 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5d00c80
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+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
 getname_flags+0xb9/0x500 fs/namei.c:141
 getname fs/namei.c:212 [inline]
 do_rmdir+0xcb/0x480 fs/namei.c:4055
 __do_sys_unlinkat fs/namei.c:4252 [inline]
 __se_sys_unlinkat fs/namei.c:4246 [inline]
 __x64_sys_unlinkat+0xb6/0xe0 fs/namei.c:4246
 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
 bpf_check+0x8371/0x9cf0 kernel/bpf/verifier.c:9731
 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

Memory state around the buggy address:
 ffff8881eac7b080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881eac7b100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881eac7b180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff8881eac7b200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881eac7b280: 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 1eb15d067 P4D 1eb15d067 PUD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 3788 Comm: syz.3.963 Tainted: G    B   W         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: 00010202
RAX: ffffffff8150a590 RBX: 0000000000000101 RCX: ffff8881e1f95e80
RDX: 0000000080000101 RSI: 0000000000000000 RDI: ffff8881eac7b1c0
RBP: ffff8881f6e09d30 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103edc1398 R11: 1ffff1103edc1398 R12: 00000000ffffb318
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881eac7b1c0
FS:  00007f11e73c36c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001d640e000 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:unlock_page_memcg+0x0/0xe0 mm/memcontrol.c:2167
Code: c3 28 05 00 00 48 89 df 4c 89 fe e8 aa a1 9a 02 e8 a5 df bd ff 5b 41 5c 41 5d 41 5e 41 5f 5d c3 66 2e 0f 1f 84 00 00 00 00 00 <55> 48 89 e5 41 57 41 56 41 55 41 54 53 48 89 fb 49 bc 00 00 00 00
RSP: 0018:ffff8881e0b875d0 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: ffffffff81880249 RBX: ffffea000766b6c0 RCX: ffff8881e1f95e80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea000766b6c0
RBP: ffff8881e0b87610 R08: dffffc0000000000 R09: fffff94000ecd6df
R10: fffff94000ecd6df R11: 1ffffd4000ecd6de R12: ffffea000766b6d8
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
 zap_pte_range mm/memory.c:1105 [inline]
 zap_pmd_range mm/memory.c:1222 [inline]
 zap_pud_range mm/memory.c:1251 [inline]
 zap_p4d_range mm/memory.c:1272 [inline]
 unmap_page_range+0xe8f/0x1b20 mm/memory.c:1293
 unmap_single_vma mm/memory.c:1338 [inline]
 unmap_vmas+0x245/0x340 mm/memory.c:1370
 exit_mmap+0x2bb/0x520 mm/mmap.c:3191
 __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
 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
RIP: 0033:0x7f11e8d5a969
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:00007f11e73c3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: fffffffffffffff5 RBX: 00007f11e8f81fa0 RCX: 00007f11e8d5a969
RDX: 0000000000000080 RSI: 0000200000000280 RDI: 0000000000000005
RBP: 00007f11e8ddcab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f11e8f81fa0 R15: 00007ffe98de6f98
Modules linked in:
CR2: 0000000000000000
---[ end trace a835f6ea0e3bc0d7 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09cf0 EFLAGS: 00010202
RAX: ffffffff8150a590 RBX: 0000000000000101 RCX: ffff8881e1f95e80
RDX: 0000000080000101 RSI: 0000000000000000 RDI: ffff8881eac7b1c0
RBP: ffff8881f6e09d30 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103edc1398 R11: 1ffff1103edc1398 R12: 00000000ffffb318
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881eac7b1c0
FS:  00007f11e73c36c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001d640e000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	00 00                	add    %al,(%rax)
   2:	41 89 f7             	mov    %esi,%r15d
   5:	49 89 fe             	mov    %rdi,%r14
   8:	43 8d 3c 3f          	lea    (%r15,%r15,1),%edi
   c:	46 8d 24 fd 7b 71 f5 	lea    0x75f5717b(,%r15,8),%r12d
  13:	75
  14:	83 ff 04             	cmp    $0x4,%edi
  17:	0f 82 87 00 00 00    	jb     0xa4
  1d:	45 89 e3             	mov    %r12d,%r11d
  20:	44 89 e1             	mov    %r12d,%ecx
  23:	4c 89 f6             	mov    %r14,%rsi
  26:	03 0e                	add    (%rsi),%ecx
* 28:	44 03 5e 04          	add    0x4(%rsi),%r11d <-- trapping instruction
  2c:	44 03 66 08          	add    0x8(%rsi),%r12d
  30:	45 89 e0             	mov    %r12d,%r8d
  33:	41 c1 c0 04          	rol    $0x4,%r8d
  37:	44 29 e1             	sub    %r12d,%ecx
  3a:	41 31 c8             	xor    %ecx,%r8d
  3d:	45                   	rex.RB