==================================================================
BUG: KASAN: slab-use-after-free in timer_is_static_object+0x35/0x80 kernel/time/timer.c:691
Read of size 8 at addr ffff88802fbc1898 by task syz.1.2505/16213

CPU: 1 UID: 0 PID: 16213 Comm: syz.1.2505 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 timer_is_static_object+0x35/0x80 kernel/time/timer.c:691
 lookup_object_or_alloc lib/debugobjects.c:679 [inline]
 debug_object_activate+0x141/0x580 lib/debugobjects.c:820
 debug_timer_activate kernel/time/timer.c:793 [inline]
 __mod_timer+0xa4f/0xf30 kernel/time/timer.c:1124
 call_timer_fn+0x192/0x5a0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2373 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2385
 run_timer_base kernel/time/timer.c:2394 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404
 handle_softirqs+0x22a/0x7c0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:core_kernel_text kernel/extable.c:71 [inline]
RIP: 0010:kernel_text_address+0x3d/0xe0 kernel/extable.c:99
Code: 81 ff c8 f3 9b 8b 0f 92 c1 bd 01 00 00 00 84 c8 75 0c 48 89 fb e8 e3 f5 a4 ff 85 c0 74 0c 89 e8 5b 41 5e 5d e9 44 71 0c 0a cc <48> c7 c0 80 09 ef 8f 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f
RSP: 0018:ffffc9000bdb7158 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f87d8d9aeb9 RCX: ffff88802529bd00
RDX: 0000000000000002 RSI: 00007f87d8d9a000 RDI: ffffffffff600000
RBP: 0000000000000001 R08: 0000000000000022 R09: ffffffff8e55a360
R10: ffffc9000bdb71f8 R11: ffffffff81af9170 R12: ffff88802529bd00
R13: 1ffff11004a5385a R14: dffffc0000000000 R15: 1ffff920017b6e3e
 __kernel_text_address+0xd/0x30 kernel/extable.c:79
 unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:385
 arch_stack_walk+0xfb/0x150 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 save_stack+0x122/0x230 mm/page_owner.c:165
 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:341
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x228/0x280 mm/page_alloc.c:1884
 prep_new_page mm/page_alloc.c:1892 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3945
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5240
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2505
 shmem_alloc_folio mm/shmem.c:1918 [inline]
 shmem_alloc_and_add_folio+0x445/0xf80 mm/shmem.c:1960
 shmem_get_folio_gfp+0x5a9/0x1670 mm/shmem.c:2584
 shmem_get_folio mm/shmem.c:2690 [inline]
 shmem_write_begin+0x16c/0x330 mm/shmem.c:3343
 generic_perform_write+0x2e2/0x8f0 mm/filemap.c:4314
 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3518
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x61d/0xb90 fs/read_write.c:686
 ksys_write+0x150/0x270 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f87d8d9aeb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f87d6ff6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f87d9016180 RCX: 00007f87d8d9aeb9
RDX: 0000000000806000 RSI: 0000200000000200 RDI: 0000000000000007
RBP: 00007f87d8e08c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f87d9016218 R14: 00007f87d9016180 R15: 00007ffd925e0278
 </TASK>

Allocated by task 11217:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x3d1/0x6e0 mm/slub.c:5780
 kmalloc_noprof include/linux/slab.h:957 [inline]
 rose_add_node+0x23c/0xf00 net/rose/rose_route.c:85
 rose_rt_ioctl+0xd35/0x12a0 net/rose/rose_route.c:748
 rose_ioctl+0x3fb/0x8f0 net/rose/af_rose.c:1382
 sock_do_ioctl+0x101/0x320 net/socket.c:1254
 sock_ioctl+0x5c6/0x7f0 net/socket.c:1375
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 16217:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2540 [inline]
 slab_free mm/slub.c:6674 [inline]
 kfree+0x1be/0x650 mm/slub.c:6882
 rose_neigh_put include/net/rose.h:166 [inline]
 rose_timer_expiry+0x4cb/0x600 net/rose/rose_timer.c:183
 call_timer_fn+0x192/0x5a0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2373 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2385
 run_timer_base kernel/time/timer.c:2394 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404
 handle_softirqs+0x22a/0x7c0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697

The buggy address belongs to the object at ffff88802fbc1800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 152 bytes inside of
 freed 512-byte region [ffff88802fbc1800, ffff88802fbc1a00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88802fbc2000 pfn:0x2fbc0
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000240 ffff88813fe26c80 ffffea00015ac910 ffffea0001aeee10
raw: ffff88802fbc2000 0000000000100001 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88813fe26c80 ffffea00015ac910 ffffea0001aeee10
head: ffff88802fbc2000 0000000000100001 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000bef001 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 11187, tgid 11184 (syz.0.1386), ts 255154690535, free_ts 236631092185
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x228/0x280 mm/page_alloc.c:1884
 prep_new_page mm/page_alloc.c:1892 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3945
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5240
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
 alloc_slab_page mm/slub.c:3075 [inline]
 allocate_slab+0x86/0x3a0 mm/slub.c:3248
 new_slab mm/slub.c:3302 [inline]
 ___slab_alloc+0xd82/0x1760 mm/slub.c:4656
 __slab_alloc+0x65/0x100 mm/slub.c:4779
 __slab_alloc_node mm/slub.c:4855 [inline]
 slab_alloc_node mm/slub.c:5251 [inline]
 __do_kmalloc_node mm/slub.c:5656 [inline]
 __kmalloc_noprof+0x46c/0x7e0 mm/slub.c:5669
 kmalloc_noprof include/linux/slab.h:961 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 copy_splice_read+0x16f/0xaa0 fs/splice.c:337
 do_splice_read fs/splice.c:981 [inline]
 splice_direct_to_actor+0x4a0/0xc70 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0x195/0x290 fs/splice.c:1230
 do_sendfile+0x535/0x7d0 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1417
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 10742 tgid 10742 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xbf8/0xd70 mm/page_alloc.c:2973
 discard_slab mm/slub.c:3346 [inline]
 __put_partials+0x146/0x170 mm/slub.c:3886
 __slab_free+0x294/0x320 mm/slub.c:5956
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4953 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 kmem_cache_alloc_noprof+0x370/0x6e0 mm/slub.c:5270
 vm_area_dup+0x2b/0x680 mm/vma_init.c:123
 __split_vma+0x1d5/0xa50 mm/vma.c:513
 split_vma mm/vma.c:596 [inline]
 vma_modify+0x941/0x2010 mm/vma.c:1666
 vma_modify_flags+0x24b/0x330 mm/vma.c:1694
 mprotect_fixup+0x46a/0xa50 mm/mprotect.c:756
 do_mprotect_pkey+0x8ab/0xcd0 mm/mprotect.c:930
 __do_sys_mprotect mm/mprotect.c:951 [inline]
 __se_sys_mprotect mm/mprotect.c:948 [inline]
 __x64_sys_mprotect+0x80/0x90 mm/mprotect.c:948
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88802fbc1780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802fbc1800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802fbc1880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88802fbc1900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802fbc1980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	81 ff c8 f3 9b 8b    	cmp    $0x8b9bf3c8,%edi
   6:	0f 92 c1             	setb   %cl
   9:	bd 01 00 00 00       	mov    $0x1,%ebp
   e:	84 c8                	test   %cl,%al
  10:	75 0c                	jne    0x1e
  12:	48 89 fb             	mov    %rdi,%rbx
  15:	e8 e3 f5 a4 ff       	call   0xffa4f5fd
  1a:	85 c0                	test   %eax,%eax
  1c:	74 0c                	je     0x2a
  1e:	89 e8                	mov    %ebp,%eax
  20:	5b                   	pop    %rbx
  21:	41 5e                	pop    %r14
  23:	5d                   	pop    %rbp
  24:	e9 44 71 0c 0a       	jmp    0xa0c716d
  29:	cc                   	int3
* 2a:	48 c7 c0 80 09 ef 8f 	mov    $0xffffffff8fef0980,%rax <-- trapping instruction
  31:	48 c1 e8 03          	shr    $0x3,%rax
  35:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  3c:	fc ff df
  3f:	0f                   	.byte 0xf