==================================================================
BUG: KASAN: slab-use-after-free in timer_is_static_object+0x35/0x80 kernel/time/timer.c:691
Read of size 8 at addr ffff888056627498 by task syz-executor/5834
CPU: 0 UID: 0 PID: 5834 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
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+0x286/0x870 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x1f0 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+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:finish_task_switch+0x26b/0x950 kernel/sched/core.c:5193
Code: 0f 84 3c 01 00 00 48 85 db 0f 85 63 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 3f cd b8 09 e8 7a b9 36 00 fb 4c 8b 65 c0 <49> 8d bc 24 58 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc900040cf0b8 EFLAGS: 00000286
RAX: 040c0e593b844200 RBX: 0000000000000000 RCX: 040c0e593b844200
RDX: 0000000000000006 RSI: ffffffff8d7113f9 RDI: ffffffff8bbf08e0
RBP: ffffc900040cf110 R08: ffffffff8f7d0477 R09: 1ffffffff1efa08e
R10: dffffc0000000000 R11: fffffbfff1efa08f R12: ffff88802c670000
R13: dffffc0000000000 R14: ffff88804f183c80 R15: ffff8880b883ad98
context_switch kernel/sched/core.c:5328 [inline]
__schedule+0x17a0/0x4cc0 kernel/sched/core.c:6929
preempt_schedule_notrace+0xd1/0x110 kernel/sched/core.c:7206
preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:752
rcu_read_unlock include/linux/rcupdate.h:895 [inline]
is_bpf_text_address+0x207/0x2b0 kernel/bpf/core.c:746
kernel_text_address+0xa5/0xe0 kernel/extable.c:125
__kernel_text_address+0xd/0x40 kernel/extable.c:79
unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:369
arch_stack_walk+0xfc/0x150 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
__kasan_save_free_info+0x46/0x50 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+0x5c/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+0x19a/0x6d0 mm/slub.c:6849
copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:882 [inline]
get_entries net/ipv6/netfilter/ip6_tables.c:1039 [inline]
do_ip6t_get_ctl+0xeb0/0x1180 net/ipv6/netfilter/ip6_tables.c:1677
nf_getsockopt+0x26e/0x290 net/netfilter/nf_sockopt.c:116
ipv6_getsockopt+0x1ed/0x290 net/ipv6/ipv6_sockglue.c:1473
do_sock_getsockopt+0x372/0x450 net/socket.c:2421
__sys_getsockopt net/socket.c:2450 [inline]
__do_sys_getsockopt net/socket.c:2457 [inline]
__se_sys_getsockopt net/socket.c:2454 [inline]
__x64_sys_getsockopt+0x1a5/0x250 net/socket.c:2454
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4dd299148a
Code: ff c3 66 0f 1f 44 00 00 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb b8 0f 1f 44 00 00 49 89 ca b8 37 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 06 c3 0f 1f 44 00 00 48 c7 c2 a8 ff ff ff f7
RSP: 002b:00007fffd4cb9298 EFLAGS: 00000212 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00007fffd4cb9320 RCX: 00007f4dd299148a
RDX: 0000000000000041 RSI: 0000000000000029 RDI: 0000000000000003
RBP: 0000000000000003 R08: 00007fffd4cb92bc R09: 0079746972756365
R10: 00007fffd4cb9320 R11: 0000000000000212 R12: 00007f4dd2bb5ca0
R13: 00007fffd4cb92bc R14: 0000000000000000 R15: 00007f4dd2bb7e60
Allocated by task 6809:
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417
kasan_kmalloc include/linux/kasan.h:262 [inline]
__kmalloc_cache_noprof+0x3d5/0x6f0 mm/slub.c:5771
kmalloc_noprof include/linux/slab.h:957 [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:1382
sock_do_ioctl+0xdc/0x300 net/socket.c:1254
sock_ioctl+0x576/0x790 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+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 13639:
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
__kasan_save_free_info+0x46/0x50 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+0x5c/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+0x19a/0x6d0 mm/slub.c:6849
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+0x286/0x870 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x1f0 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+0xa6/0xc0 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 ffff888056627400
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 152 bytes inside of
freed 512-byte region [ffff888056627400, ffff888056627600)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888056624000 pfn:0x56624
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 ffff88801a026c80 ffffea0001558910 ffffea0001575f10
raw: ffff888056624000 000000000010000a 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88801a026c80 ffffea0001558910 ffffea0001575f10
head: ffff888056624000 000000000010000a 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0001598901 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 5842, tgid 5842 (syz-executor), ts 98709992995, free_ts 30164514882
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x234/0x290 mm/page_alloc.c:1845
prep_new_page mm/page_alloc.c:1853 [inline]
get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3879
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5178
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
alloc_slab_page mm/slub.c:3059 [inline]
allocate_slab+0x96/0x350 mm/slub.c:3232
new_slab mm/slub.c:3286 [inline]
___slab_alloc+0xf56/0x1990 mm/slub.c:4655
__slab_alloc+0x65/0x100 mm/slub.c:4778
__slab_alloc_node mm/slub.c:4854 [inline]
slab_alloc_node mm/slub.c:5276 [inline]
__do_kmalloc_node mm/slub.c:5649 [inline]
__kmalloc_noprof+0x471/0x7f0 mm/slub.c:5662
kmalloc_noprof include/linux/slab.h:961 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
fib6_info_alloc+0x30/0xf0 net/ipv6/ip6_fib.c:155
ip6_route_info_create+0x142/0x860 net/ipv6/route.c:3809
ip6_route_add+0x49/0x1b0 net/ipv6/route.c:3938
addrconf_prefix_route net/ipv6/addrconf.c:2488 [inline]
add_v4_addrs+0x8b3/0xbd0 net/ipv6/addrconf.c:3265
addrconf_sit_config net/ipv6/addrconf.c:3516 [inline]
addrconf_init_auto_addrs+0x2c4/0xa30 net/ipv6/addrconf.c:3554
addrconf_notify+0xacc/0x1010 net/ipv6/addrconf.c:3740
notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
call_netdevice_notifiers net/core/dev.c:2282 [inline]
__dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1
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:1394 [inline]
__free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2901
__free_pages mm/page_alloc.c:5297 [inline]
free_contig_range+0x1bd/0x4a0 mm/page_alloc.c:7141
destroy_args+0x69/0x660 mm/debug_vm_pgtable.c:958
debug_vm_pgtable+0x39f/0x3b0 mm/debug_vm_pgtable.c:1345
do_one_initcall+0x236/0x820 init/main.c:1283
do_initcall_level+0x104/0x190 init/main.c:1345
do_initcalls+0x59/0xa0 init/main.c:1361
kernel_init_freeable+0x334/0x4b0 init/main.c:1593
kernel_init+0x1d/0x1d0 init/main.c:1483
ret_from_fork+0x4bc/0x870 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:
ffff888056627380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888056627400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888056627480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888056627500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888056627580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: 0f 84 3c 01 00 00 je 0x142
6: 48 85 db test %rbx,%rbx
9: 0f 85 63 01 00 00 jne 0x172
f: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
14: 4c 8b 75 d0 mov -0x30(%rbp),%r14
18: 4c 89 e7 mov %r12,%rdi
1b: e8 3f cd b8 09 call 0x9b8cd5f
20: e8 7a b9 36 00 call 0x36b99f
25: fb sti
26: 4c 8b 65 c0 mov -0x40(%rbp),%r12
* 2a: 49 8d bc 24 58 16 00 lea 0x1658(%r12),%rdi <-- trapping instruction
31: 00
32: 48 89 f8 mov %rdi,%rax
35: 48 c1 e8 03 shr $0x3,%rax
39: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax
3e: 84 c0 test %al,%al