==================================================================
BUG: KASAN: use-after-free in rcu_cblist_dequeue+0x6c/0xb0 kernel/rcu/rcu_segcblist.c:75
Read of size 8 at addr ffff88810ba23990 by task syz.1.767/3439
CPU: 1 PID: 3439 Comm: syz.1.767 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
__dump_stack+0x21/0x24 lib/dump_stack.c:77
dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118
print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:435 [inline]
kasan_report+0x100/0x140 mm/kasan/report.c:452
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309
rcu_cblist_dequeue+0x6c/0xb0 kernel/rcu/rcu_segcblist.c:75
rcu_do_batch+0x448/0xaf0 kernel/rcu/tree.c:2484
rcu_core+0x50a/0xca0 kernel/rcu/tree.c:2735
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2748
__do_softirq+0x255/0x563 kernel/softirq.c:309
asm_call_irq_on_stack+0xf/0x20
__run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
do_softirq_own_stack+0x60/0x80 arch/x86/kernel/irq_64.c:77
invoke_softirq kernel/softirq.c:405 [inline]
__irq_exit_rcu+0x128/0x150 kernel/softirq.c:435
irq_exit_rcu+0x9/0x10 kernel/softirq.c:447
sysvec_apic_timer_interrupt+0xbf/0xe0 arch/x86/kernel/apic/apic.c:1106
asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:635
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x49/0x70 kernel/locking/spinlock.c:199
Code: 12 48 89 fb 48 c7 c7 70 73 4c 86 e8 91 3a 1c fd 48 89 df 48 83 3d 56 69 c9 01 00 74 27 e8 83 ce c8 fc 66 90 fb bf 01 00 00 00 52 c7 c1 fc 65 8b 05 57 63 7f 7b 85 c0 74 03 5b 5d c3 e8 43 63
RSP: 0018:ffffc90000df7a50 EFLAGS: 00000246
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: dffffc0000000000
RDX: 0000000040000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: ffffc90000df7a58 R08: ffffffff86c38b93 R09: 1ffffffff0d87172
R10: dffffc0000000000 R11: fffffbfff0d87173 R12: ffff8881f7156000
R13: ffff888126b9002c R14: 0000000000000000 R15: ffff888110120000
finish_lock_switch kernel/sched/core.c:3786 [inline]
finish_task_switch+0x12e/0x5a0 kernel/sched/core.c:3886
context_switch kernel/sched/core.c:4051 [inline]
__schedule+0xc0b/0x13e0 kernel/sched/core.c:4806
schedule+0x13c/0x1d0 kernel/sched/core.c:4884
freezable_schedule include/linux/freezer.h:197 [inline]
do_nanosleep+0x1b1/0x620 kernel/time/hrtimer.c:1946
hrtimer_nanosleep+0x1b6/0x400 kernel/time/hrtimer.c:1999
common_nsleep+0x8f/0xb0 kernel/time/posix-timers.c:1268
__do_sys_clock_nanosleep kernel/time/posix-timers.c:1309 [inline]
__se_sys_clock_nanosleep+0x30b/0x3a0 kernel/time/posix-timers.c:1286
__x64_sys_clock_nanosleep+0x9b/0xb0 kernel/time/posix-timers.c:1286
do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f45fcd6fd8e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffd4f74ced8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 000055557c86f500 RCX: 00007f45fcd6fd8e
RDX: 00007ffd4f74cf30 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f45fd037da0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000001de41
R13: 00007f45fd03609c R14: 000000000001db6f R15: 00007f45fd036090
Allocated by task 3446:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:430 [inline]
____kasan_kmalloc mm/kasan/common.c:509 [inline]
__kasan_kmalloc+0xd4/0x100 mm/kasan/common.c:518
kasan_kmalloc include/linux/kasan.h:254 [inline]
__kmalloc+0x19f/0x330 mm/slub.c:4038
kmalloc include/linux/slab.h:560 [inline]
kzalloc include/linux/slab.h:667 [inline]
l2tp_session_create+0x39/0xb60 net/l2tp/l2tp_core.c:1616
pppol2tp_connect+0xbf5/0x1640 net/l2tp/l2tp_ppp.c:772
__sys_connect_file net/socket.c:1867 [inline]
__sys_connect+0x3ce/0x450 net/socket.c:1884
__do_sys_connect net/socket.c:1894 [inline]
__se_sys_connect net/socket.c:1891 [inline]
__x64_sys_connect+0x7a/0x90 net/socket.c:1891
do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x61/0xcb
Freed by task 192:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362
__kasan_slab_free+0x11/0x20 mm/kasan/common.c:370
kasan_slab_free include/linux/kasan.h:220 [inline]
slab_free_hook mm/slub.c:1600 [inline]
slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1626
slab_free mm/slub.c:3208 [inline]
kfree+0xc0/0x270 mm/slub.c:4196
l2tp_session_free net/l2tp/l2tp_core.c:168 [inline]
l2tp_session_put+0xb2/0x1a0 net/l2tp/l2tp_core.c:193
l2tp_session_delete+0x3a9/0x4a0 net/l2tp/l2tp_core.c:1589
l2tp_tunnel_closeall net/l2tp/l2tp_core.c:1235 [inline]
l2tp_tunnel_del_work+0x180/0x3d0 net/l2tp/l2tp_core.c:1273
process_one_work+0x6fd/0xbc0 kernel/workqueue.c:2301
worker_thread+0xa8e/0x13c0 kernel/workqueue.c:2447
kthread+0x324/0x3b0 kernel/kthread.c:313
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
Last potentially related work creation:
kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
__kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
__call_rcu kernel/rcu/tree.c:2980 [inline]
call_rcu+0x11a/0x1090 kernel/rcu/tree.c:3054
pppol2tp_release+0x1e3/0x2b0 net/l2tp/l2tp_ppp.c:447
__sock_release net/socket.c:597 [inline]
sock_close+0xb8/0x200 net/socket.c:1287
__fput+0x2dc/0x730 fs/file_table.c:281
____fput+0x15/0x20 fs/file_table.c:314
task_work_run+0x127/0x190 kernel/task_work.c:189
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_user_mode_loop+0xcb/0xe0 kernel/entry/common.c:175
exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:202
syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:277
do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56
entry_SYSCALL_64_after_hwframe+0x61/0xcb
Second to last potentially related work creation:
kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38
__kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358
__call_rcu kernel/rcu/tree.c:2980 [inline]
call_rcu+0x11a/0x1090 kernel/rcu/tree.c:3054
fib6_info_release include/net/ip6_fib.h:346 [inline]
__ip6_del_rt+0xf5/0x150 net/ipv6/route.c:3798
ip6_del_rt+0xbe/0x110 net/ipv6/route.c:3809
__ipv6_ifa_notify+0x872/0xe70 net/ipv6/addrconf.c:6204
addrconf_ifdown+0xdb1/0x1890 net/ipv6/addrconf.c:3926
addrconf_notify+0x3bd/0xea0 net/ipv6/addrconf.c:-1
notifier_call_chain kernel/notifier.c:83 [inline]
raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:410
call_netdevice_notifiers_info net/core/dev.c:2052 [inline]
call_netdevice_notifiers_extack net/core/dev.c:2064 [inline]
call_netdevice_notifiers net/core/dev.c:2078 [inline]
dev_close_many+0x328/0x4d0 net/core/dev.c:1653
unregister_netdevice_many+0x477/0x19f0 net/core/dev.c:10756
default_device_exit_batch+0x35e/0x3c0 net/core/dev.c:11299
ops_exit_list net/core/net_namespace.c:190 [inline]
cleanup_net+0x5fe/0xb80 net/core/net_namespace.c:609
process_one_work+0x6fd/0xbc0 kernel/workqueue.c:2301
worker_thread+0xa8e/0x13c0 kernel/workqueue.c:2447
kthread+0x324/0x3b0 kernel/kthread.c:313
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
The buggy address belongs to the object at ffff88810ba23800
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 400 bytes inside of
512-byte region [ffff88810ba23800, ffff88810ba23a00)
The buggy address belongs to the page:
page:ffffea00042e8800 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88810ba21c00 pfn:0x10ba20
head:ffffea00042e8800 order:2 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 ffffea0004337108 ffffea00042dce08 ffff888100043080
raw: ffff88810ba21c00 000000000010000a 00000001ffffffff 0000000000000000
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 279, ts 21883130985, free_ts 21856450009
set_page_owner include/linux/page_owner.h:35 [inline]
post_alloc_hook mm/page_alloc.c:2456 [inline]
prep_new_page+0x176/0x190 mm/page_alloc.c:2462
get_page_from_freelist+0x225f/0x23f0 mm/page_alloc.c:4254
__alloc_pages_nodemask+0x29a/0x640 mm/page_alloc.c:5384
alloc_slab_page mm/slub.c:-1 [inline]
allocate_slab mm/slub.c:1813 [inline]
new_slab+0x84/0x3f0 mm/slub.c:1874
new_slab_objects mm/slub.c:2632 [inline]
___slab_alloc+0x2f8/0x4c0 mm/slub.c:2796
__slab_alloc+0x63/0xa0 mm/slub.c:2836
slab_alloc_node mm/slub.c:2918 [inline]
slab_alloc mm/slub.c:2960 [inline]
__kmalloc_track_caller+0x1e4/0x310 mm/slub.c:4541
__kmalloc_reserve net/core/skbuff.c:144 [inline]
__alloc_skb+0xdc/0x520 net/core/skbuff.c:212
alloc_skb include/linux/skbuff.h:1126 [inline]
nlmsg_new include/net/netlink.h:953 [inline]
rtmsg_ifa+0xfa/0x1d0 net/ipv4/devinet.c:1927
__inet_insert_ifa+0x87a/0xa80 net/ipv4/devinet.c:566
inet_rtm_newaddr+0x8cf/0x1580 net/ipv4/devinet.c:967
rtnetlink_rcv_msg+0x9e9/0xca0 net/core/rtnetlink.c:5622
netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2508
rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5640
netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
netlink_unicast+0x86c/0xa30 net/netlink/af_netlink.c:1340
netlink_sendmsg+0x949/0xb70 net/netlink/af_netlink.c:1919
page last free stack trace:
reset_page_owner include/linux/page_owner.h:28 [inline]
free_pages_prepare mm/page_alloc.c:1349 [inline]
__free_pages_ok+0x80b/0x830 mm/page_alloc.c:1629
free_the_page mm/page_alloc.c:5445 [inline]
__free_pages+0xd8/0x390 mm/page_alloc.c:5454
__free_slab+0xcf/0x190 mm/slub.c:1899
free_slab mm/slub.c:1914 [inline]
discard_slab mm/slub.c:1920 [inline]
unfreeze_partials+0x150/0x180 mm/slub.c:2415
put_cpu_partial+0xc1/0x180 mm/slub.c:2451
__slab_free+0x2c9/0x3a0 mm/slub.c:3100
do_slab_free mm/slub.c:3196 [inline]
___cache_free+0x10e/0x130 mm/slub.c:3215
qlink_free+0x50/0x90 mm/kasan/quarantine.c:157
qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x14a/0x160 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0x2f/0xe0 mm/kasan/common.c:440
kasan_slab_alloc include/linux/kasan.h:244 [inline]
slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:580
slab_alloc_node mm/slub.c:2952 [inline]
slab_alloc mm/slub.c:2960 [inline]
kmem_cache_alloc+0x15a/0x2d0 mm/slub.c:2965
kmem_cache_alloc_node include/linux/slab.h:426 [inline]
__alloc_skb+0x9e/0x520 net/core/skbuff.c:200
alloc_skb include/linux/skbuff.h:1126 [inline]
alloc_skb_with_frags+0xa3/0x560 net/core/skbuff.c:6058
sock_alloc_send_pskb+0x87f/0x9a0 net/core/sock.c:2392
Memory state around the buggy address:
ffff88810ba23880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88810ba23900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88810ba23980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88810ba23a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88810ba23a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
----------------
Code disassembly (best guess):
0: 12 48 89 adc -0x77(%rax),%cl
3: fb sti
4: 48 c7 c7 70 73 4c 86 mov $0xffffffff864c7370,%rdi
b: e8 91 3a 1c fd call 0xfd1c3aa1
10: 48 89 df mov %rbx,%rdi
13: 48 83 3d 56 69 c9 01 cmpq $0x0,0x1c96956(%rip) # 0x1c96971
1a: 00
1b: 74 27 je 0x44
1d: e8 83 ce c8 fc call 0xfcc8cea5
22: 66 90 xchg %ax,%ax
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 52 c7 c1 fc call 0xfcc1c781 <-- trapping instruction
2f: 65 8b 05 57 63 7f 7b mov %gs:0x7b7f6357(%rip),%eax # 0x7b7f638d
36: 85 c0 test %eax,%eax
38: 74 03 je 0x3d
3a: 5b pop %rbx
3b: 5d pop %rbp
3c: c3 ret
3d: e8 .byte 0xe8
3e: 43 rex.XB
3f: 63 .byte 0x63