==================================================================
BUG: KASAN: slab-use-after-free in timer_is_static_object+0x35/0x80 kernel/time/timer.c:691
Read of size 8 at addr ffff88805afbdc98 by task syz.3.1870/13543

CPU: 0 UID: 0 PID: 13543 Comm: syz.3.1870 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 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+0x16b/0x420 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+0x17e/0x5f0 kernel/time/timer.c:1747
 expire_timers kernel/time/timer.c:1798 [inline]
 __run_timers kernel/time/timer.c:2372 [inline]
 __run_timer_base+0x61a/0x860 kernel/time/timer.c:2384
 run_timer_base kernel/time/timer.c:2393 [inline]
 run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403
 handle_softirqs+0x283/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:local_lock_acquire include/linux/local_lock_internal.h:40 [inline]
RIP: 0010:__folio_batch_add_and_move+0x360/0xd20 mm/swap.c:192
Code: 00 00 e8 f3 5f c5 ff 65 48 8b 1c 25 08 c0 a0 92 49 83 c6 28 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 a0 d4 28 00 <49> 89 1e 45 31 ed eb 60 49 8d 5e 28 48 89 d8 48 c1 e8 03 42 80 3c
RSP: 0018:ffffc9000ac57480 EFLAGS: 00000246
RAX: 1ffff110170c65fc RBX: ffff888024ba5a00 RCX: 0000000000080000
RDX: ffffc9000fee7000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9000ac57570 R08: 0000000000000000 R09: ffffffff81fa4d2a
R10: dffffc0000000000 R11: fffff9400036cd97 R12: ffffea0001b66c80
R13: 0000000000000000 R14: ffff8880b8632fe0 R15: dffffc0000000000
 shmem_alloc_and_add_folio+0xcb3/0xf60 mm/shmem.c:2006
 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2597
 shmem_fault+0x179/0x390 mm/shmem.c:2798
 __do_fault+0x138/0x390 mm/memory.c:5152
 do_read_fault mm/memory.c:5573 [inline]
 do_fault mm/memory.c:5707 [inline]
 do_pte_missing mm/memory.c:4234 [inline]
 handle_pte_fault mm/memory.c:6052 [inline]
 __handle_mm_fault+0x3611/0x5440 mm/memory.c:6195
 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6364
 faultin_page mm/gup.c:1144 [inline]
 __get_user_pages+0x1699/0x2ce0 mm/gup.c:1446
 populate_vma_page_range+0x29f/0x3a0 mm/gup.c:1880
 __mm_populate+0x24c/0x380 mm/gup.c:1983
 mm_populate include/linux/mm.h:3367 [inline]
 vm_mmap_pgoff+0x387/0x4d0 mm/util.c:585
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f655838eba9
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:00007f65561d3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f65585d6270 RCX: 00007f655838eba9
RDX: 0000000000000003 RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007f6558411e19 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f65585d6308 R14: 00007f65585d6270 R15: 00007fff5c79acc8
 </TASK>

Allocated by task 10300:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:388 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:405
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4407
 kmalloc_noprof include/linux/slab.h:905 [inline]
 rose_add_node+0x23a/0xeb0 net/rose/rose_route.c:85
 rose_rt_ioctl+0xce2/0x1240 net/rose/rose_route.c:748
 rose_ioctl+0x3ce/0x8b0 net/rose/af_rose.c:1381
 sock_do_ioctl+0xd9/0x300 net/socket.c:1238
 sock_ioctl+0x576/0x790 net/socket.c:1359
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:584
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5871:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:243 [inline]
 __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2422 [inline]
 slab_free mm/slub.c:4695 [inline]
 kfree+0x18e/0x440 mm/slub.c:4894
 rose_neigh_put include/net/rose.h:166 [inline]
 rose_timer_expiry+0x4cb/0x600 net/rose/rose_timer.c:183
 call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1747
 expire_timers kernel/time/timer.c:1798 [inline]
 __run_timers kernel/time/timer.c:2372 [inline]
 __run_timer_base+0x61a/0x860 kernel/time/timer.c:2384
 run_timer_base kernel/time/timer.c:2393 [inline]
 run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403
 handle_softirqs+0x283/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

The buggy address belongs to the object at ffff88805afbdc00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 152 bytes inside of
 freed 512-byte region [ffff88805afbdc00, ffff88805afbde00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5afbc
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801a441c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801a441c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea00016bef01 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 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5859, tgid 5859 (syz-executor), ts 88742973272, free_ts 28529761822
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:2492 [inline]
 allocate_slab+0x8a/0x370 mm/slub.c:2660
 new_slab mm/slub.c:2714 [inline]
 ___slab_alloc+0xbeb/0x1420 mm/slub.c:3901
 __slab_alloc mm/slub.c:3992 [inline]
 __slab_alloc_node mm/slub.c:4067 [inline]
 slab_alloc_node mm/slub.c:4228 [inline]
 __do_kmalloc_node mm/slub.c:4375 [inline]
 __kmalloc_noprof+0x305/0x4f0 mm/slub.c:4388
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 fib6_info_alloc+0x30/0xf0 net/ipv6/ip6_fib.c:155
 ip6_route_info_create+0x142/0x860 net/ipv6/route.c:3810
 ip6_route_add+0x49/0x1b0 net/ipv6/route.c:3939
 addrconf_prefix_route net/ipv6/addrconf.c:2488 [inline]
 fixup_permanent_addr net/ipv6/addrconf.c:3598 [inline]
 addrconf_permanent_addr+0x67f/0x9d0 net/ipv6/addrconf.c:3622
 addrconf_notify+0x887/0x1010 net/ipv6/addrconf.c:3694
 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
 call_netdevice_notifiers net/core/dev.c:2281 [inline]
 __dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1
 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9666
 do_setlink+0xc55/0x41c0 net/core/rtnetlink.c:3143
page last free pid 1 tgid 1 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2895
 __free_pages mm/page_alloc.c:5260 [inline]
 free_contig_range+0x1bd/0x4a0 mm/page_alloc.c:7091
 destroy_args+0x69/0x660 mm/debug_vm_pgtable.c:958
 debug_vm_pgtable+0x39f/0x3b0 mm/debug_vm_pgtable.c:1345
 do_one_initcall+0x233/0x820 init/main.c:1269
 do_initcall_level+0x104/0x190 init/main.c:1331
 do_initcalls+0x59/0xa0 init/main.c:1347
 kernel_init_freeable+0x334/0x4b0 init/main.c:1579
 kernel_init+0x1d/0x1d0 init/main.c:1469
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff88805afbdb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88805afbdc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805afbdc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88805afbdd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805afbdd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	e8 f3 5f c5 ff       	call   0xffc55ffa
   7:	65 48 8b 1c 25 08 c0 	mov    %gs:0xffffffff92a0c008,%rbx
   e:	a0 92
  10:	49 83 c6 28          	add    $0x28,%r14
  14:	4c 89 f0             	mov    %r14,%rax
  17:	48 c1 e8 03          	shr    $0x3,%rax
  1b:	42 80 3c 38 00       	cmpb   $0x0,(%rax,%r15,1)
  20:	74 08                	je     0x2a
  22:	4c 89 f7             	mov    %r14,%rdi
  25:	e8 a0 d4 28 00       	call   0x28d4ca
* 2a:	49 89 1e             	mov    %rbx,(%r14) <-- trapping instruction
  2d:	45 31 ed             	xor    %r13d,%r13d
  30:	eb 60                	jmp    0x92
  32:	49 8d 5e 28          	lea    0x28(%r14),%rbx
  36:	48 89 d8             	mov    %rbx,%rax
  39:	48 c1 e8 03          	shr    $0x3,%rax
  3d:	42                   	rex.X
  3e:	80                   	.byte 0x80
  3f:	3c                   	.byte 0x3c