==================================================================
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 ffff8881c90e31c8 by task syz.2.124/831

CPU: 0 PID: 831 Comm: syz.2.124 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:selinux_capable+0x1/0x430 security/selinux/hooks.c:2192
Code: c1 7c 9b 48 89 ef e8 1e 79 8a ff eb 91 89 d9 80 e1 07 80 c1 03 38 c1 7c ba 48 89 df e8 08 79 8a ff eb b0 66 0f 1f 44 00 00 55 <48> 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec e0 00 00
RSP: 0018:ffff8881ea7a78a8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff0ac8ab3 RBX: ffffffff85645580 RCX: 0000000000000000
RDX: 0000000000000015 RSI: ffffffff85ecf120 RDI: ffff8881ec1ce000
RBP: ffffffff85645598 R08: ffffffff8207fc11 R09: ffffffff819979c0
R10: ffff8881eada5e80 R11: 0000000000000003 R12: ffffffff85ecf120
R13: ffff8881ec1ce000 R14: dffffc0000000000 R15: 0000000000000015
 security_capable+0x76/0xb0 security/security.c:729
 ns_capable_common kernel/capability.c:375 [inline]
 ns_capable kernel/capability.c:396 [inline]
 capable+0x64/0xd0 kernel/capability.c:449
 bpf_prog_load kernel/bpf/syscall.c:1666 [inline]
 __do_sys_bpf kernel/bpf/syscall.c:2891 [inline]
 __se_sys_bpf+0x35fd/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: 0033:0x7f5bc4674169
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:00007f5bc2cde038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f5bc488cfa0 RCX: 00007f5bc4674169
RDX: 0000000000000070 RSI: 0000400000000440 RDI: 0000000000000005
RBP: 00007f5bc46f52a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f5bc488cfa0 R15: 00007fff09fc0608

Allocated by task 790:
 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
 shmem_alloc_inode+0x16/0x30 mm/shmem.c:3719
 alloc_inode fs/inode.c:231 [inline]
 new_inode_pseudo+0x60/0x210 fs/inode.c:966
 new_inode+0x25/0x1d0 fs/inode.c:995
 shmem_get_inode+0x10b/0x620 mm/shmem.c:2252
 shmem_symlink+0x118/0x5f0 mm/shmem.c:3068
 vfs_symlink+0x36c/0x500 fs/namei.c:4276
 do_symlinkat+0x19b/0x400 fs/namei.c:4303
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Freed by task 17:
 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
 __rcu_reclaim kernel/rcu/rcu.h:222 [inline]
 rcu_do_batch+0x492/0xa00 kernel/rcu/tree.c:2167
 rcu_core+0x4c8/0xcb0 kernel/rcu/tree.c:2387
 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292

The buggy address belongs to the object at ffff8881c90e3090
 which belongs to the cache shmem_inode_cache of size 760
The buggy address is located 312 bytes inside of
 760-byte region [ffff8881c90e3090, ffff8881c90e3388)
The buggy address belongs to the page:
page:ffffea0007243800 refcount:1 mapcount:0 mapping:ffff8881f5cfea00 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5cfea00
raw: 0000000000000000 0000000000120012 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+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
 shmem_alloc_inode+0x16/0x30 mm/shmem.c:3719
 alloc_inode fs/inode.c:231 [inline]
 new_inode_pseudo+0x60/0x210 fs/inode.c:966
 new_inode+0x25/0x1d0 fs/inode.c:995
 shmem_get_inode+0x10b/0x620 mm/shmem.c:2252
 shmem_mknod+0x54/0x1a0 mm/shmem.c:2844
 lookup_open fs/namei.c:3379 [inline]
 do_last fs/namei.c:3471 [inline]
 path_openat+0x184a/0x34b0 fs/namei.c:3683
 do_filp_open+0x20b/0x450 fs/namei.c:3713
 do_sys_open+0x39c/0x810 fs/open.c:1123
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
 netdev_run_todo+0xc44/0xdf0 net/core/dev.c:9488
 tun_detach drivers/net/tun.c:766 [inline]
 tun_chr_close+0xc1/0x130 drivers/net/tun.c:3563
 __fput+0x262/0x680 fs/file_table.c:281
 task_work_run+0x140/0x170 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x190/0x1a0 arch/x86/entry/common.c:163
 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Memory state around the buggy address:
 ffff8881c90e3080: fc fc fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881c90e3100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881c90e3180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff8881c90e3200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881c90e3280: 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 1eb94d067 P4D 1eb94d067 PUD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 773 Comm: syz.3.108 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: ffff8881eb5aaf40
RDX: 0000000080000100 RSI: 0000000000000000 RDI: ffff8881c90e31c0
RBP: ffff8881f6e09ec8 R08: ffffffff8154e50e R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffff9c70
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881c90e31c0
FS:  00007f7c6d5976c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001d6a40000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
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:free_unref_page_list+0x539/0x590 mm/page_alloc.c:3178
Code: ff 0d c7 9a 72 7e 48 8b 74 24 30 0f 85 68 fe ff ff e8 6b 61 70 ff e9 5e fe ff ff 48 8b 44 24 18 48 89 44 24 50 ff 74 24 50 9d <48> c7 44 24 60 0e 36 e0 45 48 b8 00 00 00 00 00 fc ff df 48 8b 4c
RSP: 0018:ffff8881eb927160 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000246 RBX: 1ffffd4000e820cd RCX: dffffc0000000000
RDX: ffffea0007410688 RSI: ffff8881f6e5c320 RDI: ffffea0007410648
RBP: ffff8881eb927270 R08: ffffffff8231cdb9 R09: fffffbfff0bc1869
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffea0007410668
R13: ffff8881eb927320 R14: ffff8881eb927320 R15: 000000000000000f
 release_pages+0xad8/0xb20 mm/swap.c:842
 __pagevec_release+0xc3/0x150 mm/swap.c:862
 pagevec_release include/linux/pagevec.h:88 [inline]
 shmem_undo_range+0x8a5/0x1ad0 mm/shmem.c:875
 shmem_truncate_range mm/shmem.c:997 [inline]
 shmem_evict_inode+0x218/0x9a0 mm/shmem.c:1097
 evict+0x4ea/0x960 fs/inode.c:610
 __dentry_kill+0x429/0x630 fs/dcache.c:583
 dentry_kill+0xb8/0x280 fs/dcache.c:677
 dput+0x3c/0x80 fs/dcache.c:864
 __fput+0x443/0x680 fs/file_table.c:294
 task_work_run+0x140/0x170 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xcaf/0x2bc0 kernel/exit.c:861
 do_group_exit+0x138/0x300 kernel/exit.c:984
 get_signal+0xdb1/0x1440 kernel/signal.c:2738
 do_signal+0xb0/0x11f0 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0xc0/0x1a0 arch/x86/entry/common.c:159
 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194
 ret_from_intr+0x1c/0x1c
RIP: 0033:0x7f7c6ef4e171
Code: 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 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:00004000000001e0 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f7c6f167080 RCX: 00007f7c6ef4e169
RDX: 0000400000000200 RSI: 00004000000001e0 RDI: 0000000000001000
RBP: 00007f7c6efcf2a0 R08: 0000400000000a40 R09: 0000400000000a40
R10: 0000400000000280 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f7c6f167080 R15: 00007ffd30eebbf8
Modules linked in:
CR2: 0000000000000000
---[ end trace ca7f531ae2331f11 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09d18 EFLAGS: 00010206
RAX: ffffffff8154e8ca RBX: 0000000000000100 RCX: ffff8881eb5aaf40
RDX: 0000000080000100 RSI: 0000000000000000 RDI: ffff8881c90e31c0
RBP: ffff8881f6e09ec8 R08: ffffffff8154e50e R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffff9c70
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881c90e31c0
FS:  00007f7c6d5976c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001d6a40000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	c1 7c 9b 48 89       	sarl   $0x89,0x48(%rbx,%rbx,4)
   5:	ef                   	out    %eax,(%dx)
   6:	e8 1e 79 8a ff       	call   0xff8a7929
   b:	eb 91                	jmp    0xffffff9e
   d:	89 d9                	mov    %ebx,%ecx
   f:	80 e1 07             	and    $0x7,%cl
  12:	80 c1 03             	add    $0x3,%cl
  15:	38 c1                	cmp    %al,%cl
  17:	7c ba                	jl     0xffffffd3
  19:	48 89 df             	mov    %rbx,%rdi
  1c:	e8 08 79 8a ff       	call   0xff8a7929
  21:	eb b0                	jmp    0xffffffd3
  23:	66 0f 1f 44 00 00    	nopw   0x0(%rax,%rax,1)
  29:	55                   	push   %rbp
* 2a:	48 89 e5             	mov    %rsp,%rbp <-- trapping instruction
  2d:	41 57                	push   %r15
  2f:	41 56                	push   %r14
  31:	41 55                	push   %r13
  33:	41 54                	push   %r12
  35:	53                   	push   %rbx
  36:	48 83 e4 e0          	and    $0xffffffffffffffe0,%rsp
  3a:	48                   	rex.W
  3b:	81                   	.byte 0x81
  3c:	ec                   	in     (%dx),%al
  3d:	e0 00                	loopne 0x3f