==================================================================
BUG: KASAN: use-after-free in rcu_cblist_dequeue+0x6c/0xb0 kernel/rcu/rcu_segcblist.c:75
Read of size 8 at addr ffff88811905d990 by task kworker/0:5/1195
CPU: 0 PID: 1195 Comm: kworker/0:5 Tainted: G W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: usb_hub_wq hub_event
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+0x1d7/0x600 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:console_emit_next_record+0x87e/0xa80 kernel/printk/printk.c:2797
Code: de 48 81 e6 00 02 00 00 31 ff e8 fd 83 19 00 48 81 e3 00 02 00 00 75 07 e8 2f 7f 19 00 eb 06 e8 28 7f 19 00 fb 0f b6 5c 24 17 <66> 43 c7 44 2f 20 f8 f8 43 c6 44 2f 22 f8 4f 89 74 2f 10 66 43 c7
RSP: 0018:ffffc90011efef60 EFLAGS: 00000283
RAX: ffffffff8157ef18 RBX: 0000000000000001 RCX: 0000000000100000
RDX: ffffc9000de59000 RSI: 0000000000091533 RDI: 0000000000091534
RBP: ffffc90011eff150 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520023dfddc R12: ffffc90011eff19f
R13: dffffc0000000000 R14: f8f8f8f8f8f8f8f8 R15: 1ffff920023dfdf8
console_flush_all kernel/printk/printk.c:-1 [inline]
console_unlock+0x246/0x560 kernel/printk/printk.c:2917
vprintk_emit+0x14d/0x420 kernel/printk/printk.c:2308
dev_vprintk_emit+0x32f/0x3e4 drivers/base/core.c:4934
dev_printk_emit+0xeb/0x13c drivers/base/core.c:4945
__dev_printk+0x17f/0x1b0 drivers/base/core.c:4957
_dev_notice+0x11b/0x178 drivers/base/core.c:5002
usb_parse_configuration drivers/usb/core/config.c:686 [inline]
usb_get_configuration+0x4739/0x4cb0 drivers/usb/core/config.c:973
usb_enumerate_device drivers/usb/core/hub.c:2516 [inline]
usb_new_device+0x12c/0x1500 drivers/usb/core/hub.c:2654
hub_port_connect drivers/usb/core/hub.c:5594 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5734 [inline]
port_event drivers/usb/core/hub.c:5898 [inline]
hub_event+0x27fb/0x4310 drivers/usb/core/hub.c:5980
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
Allocated by task 2264:
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 760:
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 ffff88811905d800
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 400 bytes inside of
512-byte region [ffff88811905d800, ffff88811905da00)
The buggy address belongs to the physical page:
page:ffffea0004641700 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11905c
head:ffffea0004641700 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 24, tgid 24 (kworker/1:0), ts 92130708425, free_ts 92017287050
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]
nlmsg_new include/net/netlink.h:987 [inline]
inet6_ifa_notify net/ipv6/addrconf.c:5569 [inline]
__ipv6_ifa_notify+0x200/0xe80 net/ipv6/addrconf.c:6227
ipv6_ifa_notify net/ipv6/addrconf.c:6279 [inline]
addrconf_dad_completed+0x192/0xe80 net/ipv6/addrconf.c:4283
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_pages+0x82/0x90 mm/page_alloc.c:6032
__stack_depot_save+0x45f/0x490 lib/stackdepot.c:506
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_set_track+0x60/0x70 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+0x12d/0x300 mm/slub.c:3737
kfree_skbmem+0x10c/0x180 net/core/skbuff.c:-1
__kfree_skb net/core/skbuff.c:874 [inline]
kfree_skb_reason+0xdc/0x230 net/core/skbuff.c:896
kfree_skb include/linux/skbuff.h:1271 [inline]
ip6_finish_output2+0xb8e/0x18b0 net/ipv6/ip6_output.c:111
__ip6_finish_output net/ipv6/ip6_output.c:205 [inline]
ip6_finish_output+0x60b/0xbe0 net/ipv6/ip6_output.c:216
NF_HOOK_COND include/linux/netfilter.h:294 [inline]
ip6_output+0x1fa/0x410 net/ipv6/ip6_output.c:237
Memory state around the buggy address:
ffff88811905d880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88811905d900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811905d980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88811905da00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88811905da80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
----------------
Code disassembly (best guess):
0: de 48 81 fimuls -0x7f(%rax)
3: e6 00 out %al,$0x0
5: 02 00 add (%rax),%al
7: 00 31 add %dh,(%rcx)
9: ff ljmp (bad)
a: e8 fd 83 19 00 call 0x19840c
f: 48 81 e3 00 02 00 00 and $0x200,%rbx
16: 75 07 jne 0x1f
18: e8 2f 7f 19 00 call 0x197f4c
1d: eb 06 jmp 0x25
1f: e8 28 7f 19 00 call 0x197f4c
24: fb sti
25: 0f b6 5c 24 17 movzbl 0x17(%rsp),%ebx
* 2a: 66 43 c7 44 2f 20 f8 movw $0xf8f8,0x20(%r15,%r13,1) <-- trapping instruction
31: f8
32: 43 c6 44 2f 22 f8 movb $0xf8,0x22(%r15,%r13,1)
38: 4f 89 74 2f 10 mov %r14,0x10(%r15,%r13,1)
3d: 66 data16
3e: 43 rex.XB
3f: c7 .byte 0xc7