==================================================================
BUG: KASAN: use-after-free in rcu_cblist_dequeue+0x6c/0xb0 kernel/rcu/rcu_segcblist.c:75
Read of size 8 at addr ffff88810e00c190 by task syz.4.583/2185
CPU: 1 PID: 2185 Comm: syz.4.583 Tainted: G W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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+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:pte_lockptr include/linux/mm.h:2727 [inline]
RIP: 0010:zap_pte_range mm/memory.c:1439 [inline]
RIP: 0010:zap_pmd_range mm/memory.c:1599 [inline]
RIP: 0010:zap_pud_range mm/memory.c:1628 [inline]
RIP: 0010:zap_p4d_range mm/memory.c:1649 [inline]
RIP: 0010:unmap_page_range+0xaa6/0x2360 mm/memory.c:1670
Code: 24 48 4c 8b 3c 24 4d 89 fd ba 10 00 00 00 48 8d bc 24 70 01 00 00 31 f6 e8 37 ed 0b 00 48 8b 84 24 c0 00 00 00 42 80 3c 30 00 <74> 08 48 89 df e8 50 ea 0b 00 48 8b 1b 48 c7 84 24 f0 00 00 00 00
RSP: 0018:ffffc90010fa77a0 EFLAGS: 00000246
RAX: 1ffff11027aecae4 RBX: ffff88813d765720 RCX: 0000000000000000
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc90010fa7920
RBP: ffffc90010fa7970 R08: ffffc90010fa791f R09: ffffc90010fa7910
R10: dffffc0000000000 R11: fffff520021f4f24 R12: 00007f4a1c9e7000
R13: 00007f4a1c9a1000 R14: dffffc0000000000 R15: 00007f4a1c9a1000
unmap_single_vma mm/memory.c:1716 [inline]
unmap_vmas+0x34c/0x480 mm/memory.c:1756
exit_mmap+0x2a4/0xc10 mm/mmap.c:3371
__mmput+0x92/0x340 kernel/fork.c:1319
mmput+0x4b/0x150 kernel/fork.c:1343
exit_mm kernel/exit.c:569 [inline]
do_exit+0xa51/0x2850 kernel/exit.c:874
do_group_exit+0x21b/0x2e0 kernel/exit.c:1030
__do_sys_exit_group kernel/exit.c:1041 [inline]
__se_sys_exit_group kernel/exit.c:1039 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1039
x64_sys_call+0x7b4/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
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: 0033:0x7f4a1c79ce59
Code: Unable to access opcode bytes at 0x7f4a1c79ce2f.
RSP: 002b:00007ffe76ef92a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4a1c79ce59
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffe76ef930c R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 000000000000007a
R13: 00000000000927c0 R14: 00000000000199cc R15: 00007ffe76ef9360
Allocated by task 2186:
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:1609
pppol2tp_connect+0xbf5/0x1640 net/l2tp/l2tp_ppp.c:771
__sys_connect_file net/socket.c:2000 [inline]
__sys_connect+0x3da/0x460 net/socket.c:2017
__do_sys_connect net/socket.c:2027 [inline]
__se_sys_connect net/socket.c:2024 [inline]
__x64_sys_connect+0x7a/0x90 net/socket.c:2024
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 313:
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:1582
l2tp_tunnel_closeall net/l2tp/l2tp_core.c:1228 [inline]
l2tp_tunnel_del_work+0x199/0x410 net/l2tp/l2tp_core.c:1266
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:1389
__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
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0x9b/0xb0 kernel/entry/common.c:177
exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
The buggy address belongs to the object at ffff88810e00c000
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 400 bytes inside of
512-byte region [ffff88810e00c000, ffff88810e00c200)
The buggy address belongs to the physical page:
page:ffffea0004380300 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10e00c
head:ffffea0004380300 order:2 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 ffffea0004ca0900 dead000000000003 ffff888100042f00
raw: 0000000000000000 0000000080100010 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 1, tgid 1 (swapper/0), ts 2439583322, free_ts 0
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2672
prep_new_page+0x1c/0x110 mm/page_alloc.c:2679
get_page_from_freelist+0x2ca9/0x2d20 mm/page_alloc.c:4586
__alloc_pages+0x1fa/0x610 mm/page_alloc.c:5930
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
kmalloc_trace+0x29/0xb0 mm/slab_common.c:1028
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:699 [inline]
dev_pm_qos_constraints_allocate+0x53/0x3f0 drivers/base/power/qos.c:202
__dev_pm_qos_add_request+0x132/0x3e0 drivers/base/power/qos.c:346
dev_pm_qos_add_request+0x37/0x50 drivers/base/power/qos.c:396
usb_hub_create_port_device+0x4cb/0xbe0 drivers/usb/core/port.c:764
hub_configure drivers/usb/core/hub.c:1708 [inline]
hub_probe+0x205d/0x2c00 drivers/usb/core/hub.c:1975
usb_probe_interface+0x621/0xb30 drivers/usb/core/driver.c:397
page_owner free stack trace missing
Memory state around the buggy address:
ffff88810e00c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88810e00c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88810e00c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88810e00c200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88810e00c280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
----------------
Code disassembly (best guess):
0: 24 48 and $0x48,%al
2: 4c 8b 3c 24 mov (%rsp),%r15
6: 4d 89 fd mov %r15,%r13
9: ba 10 00 00 00 mov $0x10,%edx
e: 48 8d bc 24 70 01 00 lea 0x170(%rsp),%rdi
15: 00
16: 31 f6 xor %esi,%esi
18: e8 37 ed 0b 00 call 0xbed54
1d: 48 8b 84 24 c0 00 00 mov 0xc0(%rsp),%rax
24: 00
25: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1)
* 2a: 74 08 je 0x34 <-- trapping instruction
2c: 48 89 df mov %rbx,%rdi
2f: e8 50 ea 0b 00 call 0xbea84
34: 48 8b 1b mov (%rbx),%rbx
37: 48 rex.W
38: c7 .byte 0xc7
39: 84 24 f0 test %ah,(%rax,%rsi,8)
3c: 00 00 add %al,(%rax)