==================================================================
BUG: KASAN: slab-use-after-free in timer_is_static_object+0x80/0x90 kernel/time/timer.c:691
Read of size 8 at addr ffff888062f02c98 by task syz.8.3030/17774

CPU: 1 UID: 0 PID: 17774 Comm: syz.8.3030 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 timer_is_static_object+0x80/0x90 kernel/time/timer.c:691
 lookup_object_or_alloc.part.0+0x420/0x590 lib/debugobjects.c:679
 lookup_object_or_alloc lib/debugobjects.c:665 [inline]
 debug_object_activate+0x326/0x4c0 lib/debugobjects.c:820
 debug_timer_activate kernel/time/timer.c:793 [inline]
 __mod_timer+0x814/0xd30 kernel/time/timer.c:1124
 add_timer+0x62/0x90 kernel/time/timer.c:1249
 call_timer_fn+0x19a/0x620 kernel/time/timer.c:1747
 expire_timers kernel/time/timer.c:1798 [inline]
 __run_timers+0x6ef/0x960 kernel/time/timer.c:2372
 __run_timer_base kernel/time/timer.c:2384 [inline]
 __run_timer_base kernel/time/timer.c:2376 [inline]
 run_timer_base+0x114/0x190 kernel/time/timer.c:2393
 run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2403
 handle_softirqs+0x219/0x8e0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1052
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x24/0x2f0 kernel/locking/lockdep.c:5876
Code: 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 41 54 49 89 f4 53 48 89 fb 48 83 ec 18 65 48 8b 05 39 ed 08 12 48 89 44 24 10 <31> c0 0f 1f 44 00 00 65 8b 05 52 ed 08 12 83 f8 07 0f 87 38 02 00
RSP: 0018:ffffc9000c2ff438 EFLAGS: 00000292
RAX: 38cbe6c9fcc61900 RBX: ffff8880413ed430 RCX: ffffc9000d9dd000
RDX: 0000000000080000 RSI: ffffffff81ffd842 RDI: ffff8880413ed430
RBP: 0000000000000342 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffffffff81ffd842
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880413ed418
 __raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline]
 _raw_spin_unlock+0x16/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 shmem_recalc_inode+0x172/0x1a0 mm/shmem.c:462
 shmem_alloc_and_add_folio+0x82d/0xc20 mm/shmem.c:1970
 shmem_get_folio_gfp+0x67f/0x1610 mm/shmem.c:2535
 shmem_fault+0x1fe/0xa30 mm/shmem.c:2736
 __do_fault+0x10d/0x490 mm/memory.c:5281
 do_read_fault mm/memory.c:5716 [inline]
 do_fault mm/memory.c:5850 [inline]
 do_pte_missing+0xf4a/0x3ba0 mm/memory.c:4362
 handle_pte_fault mm/memory.c:6195 [inline]
 __handle_mm_fault+0x1556/0x2aa0 mm/memory.c:6336
 handle_mm_fault+0x589/0xd10 mm/memory.c:6505
 faultin_page mm/gup.c:1126 [inline]
 __get_user_pages+0x54e/0x3530 mm/gup.c:1428
 populate_vma_page_range+0x267/0x3f0 mm/gup.c:1860
 __mm_populate+0x1d8/0x380 mm/gup.c:1963
 mm_populate include/linux/mm.h:3478 [inline]
 vm_mmap_pgoff+0x37f/0x470 mm/util.c:586
 ksys_mmap_pgoff+0x7d/0x5c0 mm/mmap.c:604
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline]
 __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc16db8f749
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:00007fc16eae2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fc16dde5fa0 RCX: 00007fc16db8f749
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007fc16dc13f91 R08: ffffffffffffffff R09: 0000000000003000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc16dde6038 R14: 00007fc16dde5fa0 R15: 00007ffd726741f8
 </TASK>

Allocated by task 15642:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417
 kmalloc_noprof include/linux/slab.h:957 [inline]
 rose_add_node net/rose/rose_route.c:85 [inline]
 rose_rt_ioctl+0x880/0x2580 net/rose/rose_route.c:748
 rose_ioctl+0x64d/0x7c0 net/rose/af_rose.c:1381
 sock_do_ioctl+0x118/0x280 net/socket.c:1254
 sock_ioctl+0x227/0x6b0 net/socket.c:1375
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 0:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 __kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:587
 kasan_save_free_info mm/kasan/kasan.h:406 [inline]
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2543 [inline]
 slab_free mm/slub.c:6642 [inline]
 kfree+0x2b8/0x6d0 mm/slub.c:6849
 rose_neigh_put include/net/rose.h:166 [inline]
 rose_timer_expiry+0x53f/0x630 net/rose/rose_timer.c:183
 call_timer_fn+0x19a/0x620 kernel/time/timer.c:1747
 expire_timers kernel/time/timer.c:1798 [inline]
 __run_timers+0x6ef/0x960 kernel/time/timer.c:2372
 __run_timer_base kernel/time/timer.c:2384 [inline]
 __run_timer_base kernel/time/timer.c:2376 [inline]
 run_timer_base+0x114/0x190 kernel/time/timer.c:2393
 run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2403
 handle_softirqs+0x219/0x8e0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1052
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697

The buggy address belongs to the object at ffff888062f02c00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 152 bytes inside of
 freed 512-byte region [ffff888062f02c00, ffff888062f02e00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x62f00
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 ffff88813ffa6c80 ffffea0001628c00 dead000000000002
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ffa6c80 ffffea0001628c00 dead000000000002
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea00018bc001 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 13, tgid 13 (kworker/u8:1), ts 755089056955, free_ts 754699270222
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1845
 prep_new_page mm/page_alloc.c:1853 [inline]
 get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3879
 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5178
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:3059 [inline]
 allocate_slab mm/slub.c:3232 [inline]
 new_slab+0x24a/0x360 mm/slub.c:3286
 ___slab_alloc+0xd79/0x1a50 mm/slub.c:4655
 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4778
 __slab_alloc_node mm/slub.c:4854 [inline]
 slab_alloc_node mm/slub.c:5276 [inline]
 __kmalloc_cache_noprof+0x477/0x780 mm/slub.c:5766
 kmalloc_noprof include/linux/slab.h:957 [inline]
 batadv_forw_packet_alloc+0x3ad/0x4e0 net/batman-adv/send.c:506
 batadv_iv_ogm_aggregate_new+0x13c/0x4c0 net/batman-adv/bat_iv_ogm.c:570
 batadv_iv_ogm_queue_add net/batman-adv/bat_iv_ogm.c:677 [inline]
 batadv_iv_ogm_schedule_buff+0x9c2/0x14c0 net/batman-adv/bat_iv_ogm.c:841
 batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:873 [inline]
 batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:866 [inline]
 batadv_iv_send_outstanding_bat_ogm_packet+0x329/0x920 net/batman-adv/bat_iv_ogm.c:1709
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
page last free pid 5871 tgid 5871 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 __free_frozen_pages+0x7df/0x1160 mm/page_alloc.c:2901
 vfree+0x1fd/0xb50 mm/vmalloc.c:3440
 delayed_vfree_work+0x56/0x70 mm/vmalloc.c:3359
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888062f02b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888062f02c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888062f02c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888062f02d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888062f02d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	90                   	nop
   1:	90                   	nop
   2:	90                   	nop
   3:	90                   	nop
   4:	90                   	nop
   5:	90                   	nop
   6:	f3 0f 1e fa          	endbr64
   a:	41 57                	push   %r15
   c:	41 56                	push   %r14
   e:	41 55                	push   %r13
  10:	41 54                	push   %r12
  12:	49 89 f4             	mov    %rsi,%r12
  15:	53                   	push   %rbx
  16:	48 89 fb             	mov    %rdi,%rbx
  19:	48 83 ec 18          	sub    $0x18,%rsp
  1d:	65 48 8b 05 39 ed 08 	mov    %gs:0x1208ed39(%rip),%rax        # 0x1208ed5e
  24:	12
  25:	48 89 44 24 10       	mov    %rax,0x10(%rsp)
* 2a:	31 c0                	xor    %eax,%eax <-- trapping instruction
  2c:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  31:	65 8b 05 52 ed 08 12 	mov    %gs:0x1208ed52(%rip),%eax        # 0x1208ed8a
  38:	83 f8 07             	cmp    $0x7,%eax
  3b:	0f                   	.byte 0xf
  3c:	87 38                	xchg   %edi,(%rax)
  3e:	02 00                	add    (%rax),%al