==================================================================
BUG: KASAN: slab-use-after-free in timer_is_static_object+0x35/0x80 kernel/time/timer.c:691
Read of size 8 at addr ffff8880497f2498 by task syz.4.9240/2721
CPU: 0 UID: 0 PID: 2721 Comm: syz.4.9240 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:kasan_check_range+0x1dd/0x2c0 mm/kasan/generic.c:200
Code: e4 49 0f 49 dc 48 83 e3 f8 49 29 dc 74 12 41 80 3b 00 0f 85 b8 00 00 00 49 ff c3 49 ff cc 75 ee 5b 41 5c 41 5d 41 5e 41 5f 5d fe 75 24 09 cc 45 84 ff 75 63 41 f7 c7 00 ff 00 00 75 5f 41 f7
RSP: 0018:ffffc90002ed6f78 EFLAGS: 00000256
RAX: 1ffffd4000252901 RBX: 1ffffd4000252966 RCX: ffffffff8217f89e
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffea0001294b34
RBP: ffffc90002ed7170 R08: ffffea0001294b37 R09: 1ffffd4000252966
R10: dffffc0000000000 R11: fffff94000252967 R12: 0000000000000000
R13: ffffea0001294b34 R14: ffffea0001294b08 R15: 0000000000000000
instrument_atomic_read include/linux/instrumented.h:68 [inline]
atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
page_ref_count include/linux/page_ref.h:67 [inline]
page_expected_state mm/page_alloc.c:1039 [inline]
check_new_page mm/page_alloc.c:1745 [inline]
check_new_pages mm/page_alloc.c:1759 [inline]
__rmqueue_pcplist+0x1a5e/0x1df0 mm/page_alloc.c:3274
rmqueue_pcplist mm/page_alloc.c:3304 [inline]
rmqueue mm/page_alloc.c:3335 [inline]
get_page_from_freelist+0x91f/0x2440 mm/page_alloc.c:3876
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5178
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2435
shmem_alloc_folio mm/shmem.c:1870 [inline]
shmem_alloc_and_add_folio+0x423/0xf40 mm/shmem.c:1912
shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2535
shmem_fault+0x179/0x390 mm/shmem.c:2736
__do_fault+0x138/0x390 mm/memory.c:5281
do_read_fault mm/memory.c:5716 [inline]
do_fault mm/memory.c:5850 [inline]
do_pte_missing mm/memory.c:4362 [inline]
handle_pte_fault mm/memory.c:6195 [inline]
__handle_mm_fault+0x35e3/0x5400 mm/memory.c:6336
handle_mm_fault+0x40a/0x8e0 mm/memory.c:6505
faultin_page mm/gup.c:1126 [inline]
__get_user_pages+0x165c/0x2a00 mm/gup.c:1428
populate_vma_page_range+0x29f/0x3a0 mm/gup.c:1860
__mm_populate+0x24c/0x380 mm/gup.c:1963
mm_populate include/linux/mm.h:3478 [inline]
vm_mmap_pgoff+0x387/0x4d0 mm/util.c:586
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: 0033:0x7fb32278f749
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:00007fb320591038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fb3229e6270 RCX: 00007fb32278f749
RDX: 0000000000000003 RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007fb322813f91 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb3229e6308 R14: 00007fb3229e6270 R15: 00007ffd92bc2e58
Allocated by task 30768:
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 2727:
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 ffff8880497f2400
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 152 bytes inside of
freed 512-byte region [ffff8880497f2400, ffff8880497f2600)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x497f0
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 ffff88801a026c80 ffffea0001636200 dead000000000002
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801a026c80 ffffea0001636200 dead000000000002
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea000125fc01 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 20128, tgid 20121 (syz.0.5548), ts 509683388456, free_ts 507470406408
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]
__kmalloc_cache_noprof+0x411/0x6f0 mm/slub.c:5766
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
mca_alloc net/ipv6/mcast.c:871 [inline]
__ipv6_dev_mc_inc+0x44f/0xa50 net/ipv6/mcast.c:961
ipv6_add_dev+0xe63/0x1370 net/ipv6/addrconf.c:475
addrconf_notify+0x794/0x1010 net/ipv6/addrconf.c:3650
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]
register_netdevice+0x1608/0x1ae0 net/core/dev.c:11421
register_netdev+0x40/0x60 net/core/dev.c:11499
ip6gre_init_net+0x291/0x3c0 net/ipv6/ip6_gre.c:1599
ops_init+0x35c/0x5c0 net/core/net_namespace.c:137
page last free pid 5829 tgid 5829 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
__slab_free+0x2e7/0x390 mm/slub.c:5970
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:352
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4978 [inline]
slab_alloc_node mm/slub.c:5288 [inline]
kmem_cache_alloc_noprof+0x367/0x6e0 mm/slub.c:5295
getname_flags+0xb8/0x540 fs/namei.c:146
getname include/linux/fs.h:2924 [inline]
__do_sys_mkdirat fs/namei.c:4503 [inline]
__se_sys_mkdirat fs/namei.c:4501 [inline]
__x64_sys_mkdirat+0x7a/0xa0 fs/namei.c:4501
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
Memory state around the buggy address:
ffff8880497f2380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880497f2400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880497f2480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880497f2500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880497f2580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: e4 49 in $0x49,%al
2: 0f 49 dc cmovns %esp,%ebx
5: 48 83 e3 f8 and $0xfffffffffffffff8,%rbx
9: 49 29 dc sub %rbx,%r12
c: 74 12 je 0x20
e: 41 80 3b 00 cmpb $0x0,(%r11)
12: 0f 85 b8 00 00 00 jne 0xd0
18: 49 ff c3 inc %r11
1b: 49 ff cc dec %r12
1e: 75 ee jne 0xe
20: 5b pop %rbx
21: 41 5c pop %r12
23: 41 5d pop %r13
25: 41 5e pop %r14
27: 41 5f pop %r15
29: 5d pop %rbp
* 2a: e9 fe 75 24 09 jmp 0x924762d <-- trapping instruction
2f: cc int3
30: 45 84 ff test %r15b,%r15b
33: 75 63 jne 0x98
35: 41 f7 c7 00 ff 00 00 test $0xff00,%r15d
3c: 75 5f jne 0x9d
3e: 41 rex.B
3f: f7 .byte 0xf7