==================================================================
BUG: KASAN: use-after-free in rcu_cblist_dequeue+0x6c/0xb0 kernel/rcu/rcu_segcblist.c:75
Read of size 8 at addr ffff888111dd7990 by task syz.3.27/394
CPU: 0 PID: 394 Comm: syz.3.27 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:88
dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
print_address_description+0x71/0x200 mm/kasan/report.c:316
print_report+0x4a/0x60 mm/kasan/report.c:420
kasan_report+0x122/0x150 mm/kasan/report.c:524
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:351
rcu_cblist_dequeue+0x6c/0xb0 kernel/rcu/rcu_segcblist.c:75
rcu_do_batch+0x4bc/0xc30 kernel/rcu/tree.c:2285
rcu_core+0x486/0xf00 kernel/rcu/tree.c:2557
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2574
handle_softirqs+0x1dd/0x5f0 kernel/softirq.c:642
__do_softirq kernel/softirq.c:680 [inline]
invoke_softirq kernel/softirq.c:497 [inline]
__irq_exit_rcu+0x52/0xf0 kernel/softirq.c:729
irq_exit_rcu+0x9/0x10 kernel/softirq.c:741
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:should_fail_ex+0xa/0x510 lib/fault-inject.c:104
Code: df e8 aa 11 2a ff e9 55 ff ff ff 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 b8 84 6f ae f0 55 48 89 e5 41 57 41 56 41 55 <41> 54 53 48 83 ec 20 89 55 d0 49 89 f7 49 89 fe 48 ba 00 00 00 00
RSP: 0018:ffffc9000dc3fa48 EFLAGS: 00000246
RAX: ffffffff828cff59 RBX: 0000000000000008 RCX: 0000000000080000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff873ca040
RBP: ffffc9000dc3fa60 R08: ffff888115de9440 R09: 0000000000000004
R10: 0000000000000008 R11: 0000000000000002 R12: dffffc0000000000
R13: 0000200000138d90 R14: ffffc9000dc3fb40 R15: 0000200000138d90
should_fail+0xb/0x10 lib/fault-inject.c:157
should_fail_usercopy+0x1a/0x20 lib/fault-inject-usercopy.c:37
_copy_from_user+0x1e/0xc0 lib/usercopy.c:15
copy_from_user include/linux/uaccess.h:161 [inline]
copy_from_sockptr_offset include/linux/sockptr.h:48 [inline]
tcp_repair_options_est+0x13e/0x450 net/ipv4/tcp.c:3298
do_tcp_setsockopt+0x1561/0x1b90 net/ipv4/tcp.c:3710
tcp_setsockopt+0x54/0x100 net/ipv4/tcp.c:3862
sock_common_setsockopt+0xb1/0xc0 net/core/sock.c:3723
__sys_setsockopt+0x2ff/0x4e0 net/socket.c:2278
__do_sys_setsockopt net/socket.c:2289 [inline]
__se_sys_setsockopt net/socket.c:2286 [inline]
__x64_sys_setsockopt+0xbf/0xd0 net/socket.c:2286
x64_sys_call+0x124/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:55
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc72039f559
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc72118f028 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007fc720625fa0 RCX: 00007fc72039f559
RDX: 0000000000000016 RSI: 0000000000000006 RDI: 0000000000000003
RBP: 00007fc720436b20 R08: 0000000020000328 R09: 0000000000000000
R10: 0000200000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc720626038 R14: 00007fc720625fa0 R15: 00007ffe30616668
Allocated by task 374:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505
____kasan_kmalloc mm/kasan/common.c:380 [inline]
__kasan_kmalloc+0x95/0xb0 mm/kasan/common.c:389
kasan_kmalloc include/linux/kasan.h:212 [inline]
__do_kmalloc_node mm/slab_common.c:938 [inline]
__kmalloc+0xb4/0x1e0 mm/slab_common.c:951
kmalloc include/linux/slab.h:568 [inline]
kzalloc include/linux/slab.h:699 [inline]
l2tp_session_create+0x38/0xbd0 net/l2tp/l2tp_core.c:1614
pppol2tp_connect+0xbf5/0x1640 net/l2tp/l2tp_ppp.c:771
__sys_connect_file net/socket.c:2001 [inline]
__sys_connect+0x3da/0x460 net/socket.c:2018
__do_sys_connect net/socket.c:2028 [inline]
__se_sys_connect net/socket.c:2025 [inline]
__x64_sys_connect+0x7a/0x90 net/socket.c:2025
x64_sys_call+0x88d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:43
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Freed by task 309:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516
____kasan_slab_free+0x132/0x180 mm/kasan/common.c:242
__kasan_slab_free+0x11/0x20 mm/kasan/common.c:250
kasan_slab_free include/linux/kasan.h:178 [inline]
slab_free_hook mm/slub.c:1750 [inline]
slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1776
slab_free mm/slub.c:3712 [inline]
__kmem_cache_free+0xb7/0x1b0 mm/slub.c:3728
kfree+0x6f/0xf0 mm/slab_common.c:990
l2tp_session_free net/l2tp/l2tp_core.c:168 [inline]
l2tp_session_put+0xaf/0x1a0 net/l2tp/l2tp_core.c:193
l2tp_session_delete+0x3df/0x4d0 net/l2tp/l2tp_core.c:1587
l2tp_tunnel_closeall net/l2tp/l2tp_core.c:1233 [inline]
l2tp_tunnel_del_work+0x199/0x410 net/l2tp/l2tp_core.c:1271
process_one_work+0x717/0xc30 kernel/workqueue.c:2302
worker_thread+0xa4d/0x11d0 kernel/workqueue.c:2449
kthread+0x281/0x320 kernel/kthread.c:386
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Last potentially related work creation:
kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
__kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486
kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496
__call_rcu_common kernel/rcu/tree.c:2807 [inline]
call_rcu+0xcf/0xf50 kernel/rcu/tree.c:2926
pppol2tp_release+0x1e3/0x2b0 net/l2tp/l2tp_ppp.c:446
__sock_release net/socket.c:652 [inline]
sock_close+0xc9/0x220 net/socket.c:1390
__fput+0x1fd/0x8f0 fs/file_table.c:320
____fput+0x15/0x20 fs/file_table.c:348
task_work_run+0x1e1/0x250 kernel/task_work.c:203
exit_task_work include/linux/task_work.h:39 [inline]
do_exit+0xb0d/0x29f0 kernel/exit.c:896
__do_sys_exit kernel/exit.c:1006 [inline]
__se_sys_exit kernel/exit.c:1004 [inline]
__cfi___ia32_sys_exit+0x0/0x10 kernel/exit.c:1004
x64_sys_call+0x67/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:61
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
The buggy address belongs to the object at ffff888111dd7800
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 400 bytes inside of
512-byte region [ffff888111dd7800, ffff888111dd7a00)
The buggy address belongs to the physical page:
page:ffffea0004477500 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x111dd4
head:ffffea0004477500 order:2 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 0000000000000000 dead000000000122 ffff888100042f00
raw: 0000000000000000 0000000000100010 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 0x1d2a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 6, tgid 6 (kworker/0:0), ts 23973130441, free_ts 21993402879
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2673
prep_new_page+0x1c/0x110 mm/page_alloc.c:2680
get_page_from_freelist+0x2ca9/0x2d20 mm/page_alloc.c:4587
__alloc_pages+0x1fa/0x610 mm/page_alloc.c:5931
alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
allocate_slab mm/slub.c:1967 [inline]
new_slab+0x98/0x3e0 mm/slub.c:2020
___slab_alloc+0x70f/0xb70 mm/slub.c:3177
__slab_alloc+0x5e/0xa0 mm/slub.c:3263
slab_alloc_node mm/slub.c:3348 [inline]
__kmem_cache_alloc_node+0x204/0x2d0 mm/slub.c:3423
__do_kmalloc_node mm/slab_common.c:937 [inline]
__kmalloc_node_track_caller+0xa1/0x1e0 mm/slab_common.c:958
kmalloc_reserve net/core/skbuff.c:449 [inline]
__alloc_skb+0x226/0x4a0 net/core/skbuff.c:518
alloc_skb include/linux/skbuff.h:1322 [inline]
ndisc_alloc_skb net/ipv6/ndisc.c:423 [inline]
ndisc_send_rs+0x31d/0x870 net/ipv6/ndisc.c:707
addrconf_dad_completed+0x958/0xe80 net/ipv6/addrconf.c:4322
addrconf_dad_work+0xc1b/0x14a0 net/ipv6/addrconf.c:-1
process_one_work+0x717/0xc30 kernel/workqueue.c:2302
worker_thread+0xa4d/0x11d0 kernel/workqueue.c:2449
page last free stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
free_pages_prepare mm/page_alloc.c:1581 [inline]
free_pcp_prepare mm/page_alloc.c:1655 [inline]
free_unref_page_prepare+0x81b/0x820 mm/page_alloc.c:3622
free_unref_page+0x93/0x530 mm/page_alloc.c:3720
free_the_page mm/page_alloc.c:863 [inline]
__free_pages+0x67/0x100 mm/page_alloc.c:6021
__free_slab+0xc7/0x1a0 mm/slub.c:2044
free_slab mm/slub.c:2059 [inline]
discard_slab mm/slub.c:2065 [inline]
__unfreeze_partials+0x15a/0x190 mm/slub.c:2614
put_cpu_partial+0xa9/0x100 mm/slub.c:2690
__slab_free+0x1c4/0x280 mm/slub.c:3589
do_slab_free mm/slub.c:3666 [inline]
___cache_free+0xbf/0xd0 mm/slub.c:3722
qlink_free mm/kasan/quarantine.c:168 [inline]
qlist_free_all+0xc6/0x140 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x14a/0x170 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0x24/0x80 mm/kasan/common.c:311
kasan_slab_alloc include/linux/kasan.h:202 [inline]
slab_post_alloc_hook+0x4f/0x2d0 mm/slab.h:768
slab_alloc_node mm/slub.c:3382 [inline]
kmem_cache_alloc_node+0x179/0x330 mm/slub.c:3429
__alloc_skb+0xe8/0x4a0 net/core/skbuff.c:508
alloc_skb include/linux/skbuff.h:1322 [inline]
nlmsg_new include/net/netlink.h:987 [inline]
netlink_ack+0x373/0x1160 net/netlink/af_netlink.c:2463
netlink_rcv_skb+0x27e/0x450 net/netlink/af_netlink.c:2532
Memory state around the buggy address:
ffff888111dd7880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888111dd7900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888111dd7980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888111dd7a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888111dd7a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
----------------
Code disassembly (best guess):
0: df e8 fucomip %st(0),%st
2: aa stos %al,%es:(%rdi)
3: 11 2a adc %ebp,(%rdx)
5: ff ljmp (bad)
6: e9 55 ff ff ff jmp 0xffffff60
b: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
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: b8 84 6f ae f0 mov $0xf0ae6f84,%eax
20: 55 push %rbp
21: 48 89 e5 mov %rsp,%rbp
24: 41 57 push %r15
26: 41 56 push %r14
28: 41 55 push %r13
* 2a: 41 54 push %r12 <-- trapping instruction
2c: 53 push %rbx
2d: 48 83 ec 20 sub $0x20,%rsp
31: 89 55 d0 mov %edx,-0x30(%rbp)
34: 49 89 f7 mov %rsi,%r15
37: 49 89 fe mov %rdi,%r14
3a: 48 rex.W
3b: ba 00 00 00 00 mov $0x0,%edx