==================================================================
BUG: KASAN: slab-use-after-free in lec_arp_clear_vccs+0x6c/0x380 net/atm/lec.c:1260
Read of size 8 at addr ffff88801b7856d0 by task swapper/0/0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
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
lec_arp_clear_vccs+0x6c/0x380 net/atm/lec.c:1260
lec_arp_expire_vcc+0x17d/0x370 net/atm/lec.c:1598
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
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: 28 60 02 e9 53 e8 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 53 59 11 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffffff8e207dc0 EFLAGS: 00000246
RAX: 0000000000598765 RBX: ffffffff8199370d RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8dcd0c10 RDI: ffffffff8c073a00
RBP: ffffffff8e207eb0 R08: ffff8880b86336db R09: 1ffff110170c66db
R10: dffffc0000000000 R11: ffffed10170c66dc R12: ffffffff8fef4970
R13: 1ffffffff1c52a78 R14: 0000000000000000 R15: 0000000000000000
arch_safe_halt arch/x86/kernel/process.c:766 [inline]
default_idle+0x9/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x1bd/0x500 kernel/sched/idle.c:332
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:430
rest_init+0x2de/0x300 init/main.c:757
start_kernel+0x380/0x3d0 init/main.c:1206
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147
Allocated by task 23317:
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]
__do_kmalloc_node mm/slub.c:5657 [inline]
__kvmalloc_node_noprof+0x59a/0x8d0 mm/slub.c:7140
kvmalloc_array_node_noprof include/linux/slab.h:1122 [inline]
__alloc_bucket_spinlocks+0x64/0x160 lib/bucket_locks.c:34
alloc_ila_locks net/ipv6/ila/ila_xlat.c:29 [inline]
ila_xlat_init_net+0x77/0x120 net/ipv6/ila/ila_xlat.c:610
ops_init+0x35c/0x5c0 net/core/net_namespace.c:137
setup_net+0x118/0x340 net/core/net_namespace.c:446
copy_net_ns+0x50e/0x730 net/core/net_namespace.c:581
create_new_namespaces+0x3e7/0x6a0 kernel/nsproxy.c:130
unshare_nsproxy_namespaces+0x11a/0x160 kernel/nsproxy.c:226
ksys_unshare+0x4f4/0x900 kernel/fork.c:3171
__do_sys_unshare kernel/fork.c:3242 [inline]
__se_sys_unshare kernel/fork.c:3240 [inline]
__x64_sys_unshare+0x38/0x50 kernel/fork.c:3240
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 23317:
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
ops_exit_list net/core/net_namespace.c:199 [inline]
ops_undo_list+0x49f/0x940 net/core/net_namespace.c:252
setup_net+0x2f0/0x340 net/core/net_namespace.c:462
copy_net_ns+0x50e/0x730 net/core/net_namespace.c:581
create_new_namespaces+0x3e7/0x6a0 kernel/nsproxy.c:130
unshare_nsproxy_namespaces+0x11a/0x160 kernel/nsproxy.c:226
ksys_unshare+0x4f4/0x900 kernel/fork.c:3171
__do_sys_unshare kernel/fork.c:3242 [inline]
__se_sys_unshare kernel/fork.c:3240 [inline]
__x64_sys_unshare+0x38/0x50 kernel/fork.c:3240
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
The buggy address belongs to the object at ffff88801b785000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1744 bytes inside of
freed 2048-byte region [ffff88801b785000, ffff88801b785800)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88801b786000 pfn:0x1b780
head: order:3 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 ffff88813fe27000 ffffea0000e26a10 ffffea00011e8810
raw: ffff88801b786000 0000000000080005 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88813fe27000 ffffea0000e26a10 ffffea00011e8810
head: ffff88801b786000 0000000000080005 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea00006de001 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5815, tgid 5815 (syz-executor), ts 88966656835, free_ts 88945326376
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_node_track_caller_noprof+0x5b7/0x7f0 mm/slub.c:5768
kmalloc_reserve net/core/skbuff.c:635 [inline]
pskb_expand_head+0x228/0x1320 net/core/skbuff.c:2315
netlink_trim+0x1b3/0x2c0 net/netlink/af_netlink.c:1299
netlink_broadcast_filtered+0xd6/0x1020 net/netlink/af_netlink.c:1512
nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
nlmsg_multicast include/net/netlink.h:1184 [inline]
nlmsg_notify+0xf0/0x1a0 net/netlink/af_netlink.c:2593
rtnl_notify net/core/rtnetlink.c:958 [inline]
rtmsg_ifinfo_send net/core/rtnetlink.c:4436 [inline]
rtmsg_ifinfo_event net/core/rtnetlink.c:4452 [inline]
rtnetlink_event+0x224/0x270 net/core/rtnetlink.c:7018
notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2280 [inline]
call_netdevice_notifiers net/core/dev.c:2294 [inline]
netif_change_name+0x5e5/0x960 net/core/dev.c:1502
do_setlink+0xb6c/0x4590 net/core/rtnetlink.c:3138
page last free pid 5820 tgid 5820 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
__slab_free+0x2ce/0x320 mm/slub.c:6008
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]
__do_kmalloc_node mm/slub.c:5656 [inline]
__kmalloc_node_noprof+0x516/0x7f0 mm/slub.c:5663
kmalloc_node_noprof include/linux/slab.h:987 [inline]
qdisc_alloc+0x92/0x9e0 net/sched/sch_generic.c:951
qdisc_create_dflt+0x8e/0x4c0 net/sched/sch_generic.c:1006
attach_one_default_qdisc net/sched/sch_generic.c:1172 [inline]
netdev_for_each_tx_queue include/linux/netdevice.h:2683 [inline]
attach_default_qdiscs net/sched/sch_generic.c:1190 [inline]
dev_activate+0x378/0x1150 net/sched/sch_generic.c:1249
__dev_open+0x67a/0x830 net/core/dev.c:1704
__dev_change_flags+0x1f7/0x690 net/core/dev.c:9746
netif_change_flags+0x88/0x1a0 net/core/dev.c:9809
do_setlink+0xf82/0x4590 net/core/rtnetlink.c:3158
rtnl_changelink net/core/rtnetlink.c:3776 [inline]
__rtnl_newlink net/core/rtnetlink.c:3935 [inline]
rtnl_newlink+0x15a9/0x1be0 net/core/rtnetlink.c:4072
rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6958
netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
Memory state around the buggy address:
ffff88801b785580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88801b785600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801b785680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88801b785700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88801b785780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: 28 60 02 sub %ah,0x2(%rax)
3: e9 53 e8 02 00 jmp 0x2e85b
8: cc int3
9: cc int3
a: cc int3
b: 90 nop
c: 90 nop
d: 90 nop
e: 90 nop
f: 90 nop
10: 90 nop
11: 90 nop
12: 90 nop
13: 90 nop
14: 90 nop
15: 90 nop
16: 90 nop
17: 90 nop
18: 90 nop
19: 90 nop
1a: 90 nop
1b: f3 0f 1e fa endbr64
1f: 66 90 xchg %ax,%ax
21: 0f 00 2d 53 59 11 00 verw 0x115953(%rip) # 0x11597b
28: fb sti
29: f4 hlt
* 2a: c3 ret <-- trapping instruction
2b: cc int3
2c: cc int3
2d: cc int3
2e: cc int3
2f: cc int3
30: cc int3
31: cc int3
32: cc int3
33: cc int3
34: cc int3
35: cc int3
36: cc int3
37: cc int3
38: cc int3
39: cc int3
3a: cc int3
3b: 90 nop
3c: 90 nop
3d: 90 nop
3e: 90 nop
3f: 90 nop