==================================================================
BUG: KASAN: slab-use-after-free in llc_conn_ac_send_sabme_cmd_p_set_x+0x38a/0x420 net/llc/llc_c_ac.c:782
Read of size 1 at addr ffff88807975f010 by task pool_workqueue_/3
CPU: 1 UID: 0 PID: 3 Comm: pool_workqueue_ Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description+0x55/0x1e0 mm/kasan/report.c:378
print_report+0x58/0x70 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
llc_conn_ac_send_sabme_cmd_p_set_x+0x38a/0x420 net/llc/llc_c_ac.c:782
llc_exec_conn_trans_actions net/llc/llc_conn.c:437 [inline]
llc_conn_service net/llc/llc_conn.c:362 [inline]
llc_conn_state_process+0x4fb/0x1380 net/llc/llc_conn.c:66
llc_process_tmr_ev net/llc/llc_c_ac.c:1442 [inline]
llc_conn_tmr_common_cb+0x34a/0x780 net/llc/llc_c_ac.c:1325
call_timer_fn+0x18d/0x5f0 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2374 [inline]
__run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
run_timer_base kernel/time/timer.c:2395 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
handle_softirqs+0x226/0x860 kernel/softirq.c:645
__do_softirq kernel/softirq.c:679 [inline]
invoke_softirq kernel/softirq.c:519 [inline]
__irq_exit_rcu+0xcb/0x220 kernel/softirq.c:767
irq_exit_rcu+0x9/0x30 kernel/softirq.c:784
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lockdep_unregister_key+0x2d4/0x350 kernel/locking/lockdep.c:6678
Code: e9 a1 13 09 00 48 c7 c7 90 39 9a 96 89 c6 e8 a3 66 42 0a e9 66 fe ff ff e8 39 96 3f 0a 41 f7 c7 00 02 00 00 74 b4 fb 40 84 ed <75> b3 eb c4 90 0f 0b 90 e9 27 ff ff ff 90 0f 0b 90 e9 2f ff ff ff
RSP: 0018:ffffc90000087c80 EFLAGS: 00000246
RAX: 0000000000000046 RBX: ffff8880287a6930 RCX: 0000000000000046
RDX: ffffffff9455b4f8 RSI: ffffffff8e48da65 RDI: ffffffff8c6d8b80
RBP: ffff88801de81f00 R08: 4d00000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8ed5c6e0 R12: 0000000000000000
R13: ffff8880287a6931 R14: 0000000000001000 R15: 0000000000000a47
wq_unregister_lockdep kernel/workqueue.c:5014 [inline]
pwq_release_workfn+0x7c1/0x920 kernel/workqueue.c:5310
kthread_worker_fn+0x4eb/0xb20 kernel/kthread.c:1025
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Allocated by task 11411:
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]
__kmalloc_cache_noprof+0x321/0x600 mm/slub.c:5563
_kmalloc_noprof include/linux/slab.h:991 [inline]
_kzalloc_noprof include/linux/slab.h:1312 [inline]
llc_sap_alloc net/llc/llc_core.c:29 [inline]
llc_sap_open+0xe1/0x3b0 net/llc/llc_core.c:96
llc_ui_autobind+0x1f1/0x560 net/llc/af_llc.c:301
llc_ui_connect+0x1d7/0xd50 net/llc/af_llc.c:498
connect_socket net/socket.c:2141 [inline]
__sys_connect_file net/socket.c:2166 [inline]
__sys_connect+0x316/0x450 net/socket.c:2183
__do_sys_connect net/socket.c:2189 [inline]
__se_sys_connect net/socket.c:2186 [inline]
__x64_sys_connect+0x7a/0x90 net/socket.c:2186
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 11433:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x40/0x50 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:2748 [inline]
__rcu_free_sheaf_prepare+0x12d/0x2a0 mm/slub.c:3009
rcu_free_sheaf+0x31/0x200 mm/slub.c:6052
rcu_do_batch kernel/rcu/tree.c:2650 [inline]
rcu_core+0x926/0x1260 kernel/rcu/tree.c:2919
handle_softirqs+0x226/0x860 kernel/softirq.c:645
__do_softirq kernel/softirq.c:679 [inline]
invoke_softirq kernel/softirq.c:519 [inline]
__irq_exit_rcu+0xcb/0x220 kernel/softirq.c:767
irq_exit_rcu+0x9/0x30 kernel/softirq.c:784
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
The buggy address belongs to the object at ffff88807975f000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 16 bytes inside of
freed 2048-byte region [ffff88807975f000, ffff88807975f800)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888079758000 pfn:0x79758
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 ffff88801b042000 ffffea0001f80810 ffffea0000d6de10
raw: ffff888079758000 0000000000080006 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88801b042000 ffffea0001f80810 ffffea0000d6de10
head: ffff888079758000 0000000000080006 00000000f5000000 0000000000000000
head: 00fff00000000003 fffffffffffffe01 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5631, tgid 5631 (kworker/0:3), ts 116425666775
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871
prep_new_page mm/page_alloc.c:1879 [inline]
get_page_from_freelist+0x2209/0x2280 mm/page_alloc.c:3943
__alloc_frozen_pages_noprof+0x217/0x5a0 mm/page_alloc.c:5436
alloc_slab_page mm/slub.c:3347 [inline]
allocate_slab+0x7d/0x620 mm/slub.c:3462
new_slab mm/slub.c:3513 [inline]
refill_objects+0x2d5/0x350 mm/slub.c:7410
refill_sheaf mm/slub.c:2885 [inline]
__pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4774
alloc_from_pcs mm/slub.c:4850 [inline]
slab_alloc_node mm/slub.c:4984 [inline]
__do_kmalloc_node mm/slub.c:5413 [inline]
__kmalloc_node_track_caller_noprof+0x548/0x720 mm/slub.c:5545
kmalloc_reserve net/core/skbuff.c:637 [inline]
__alloc_skb+0x2c1/0x7a0 net/core/skbuff.c:715
alloc_skb include/linux/skbuff.h:1384 [inline]
mld_newpack+0x165/0xcb0 net/ipv6/mcast.c:1790
add_grhead net/ipv6/mcast.c:1901 [inline]
add_grec+0x119f/0x19d0 net/ipv6/mcast.c:2040
mld_send_cr net/ipv6/mcast.c:2165 [inline]
mld_ifc_work+0x6f1/0xd60 net/ipv6/mcast.c:2711
process_one_work kernel/workqueue.c:3387 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page last free pid 5388 tgid 5388 ts 52470174058 stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1418 [inline]
__free_frozen_pages+0xc93/0xd90 mm/page_alloc.c:2962
__slab_free+0x274/0x2c0 mm/slub.c:5815
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x99/0x100 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:4683 [inline]
slab_alloc_node mm/slub.c:4996 [inline]
kmem_cache_alloc_noprof+0x2b9/0x600 mm/slub.c:5010
vm_area_alloc+0x24/0x140 mm/vma_init.c:36
__mmap_new_vma mm/vma.c:2648 [inline]
__mmap_region mm/vma.c:2879 [inline]
mmap_region+0x12cb/0x2240 mm/vma.c:2964
do_mmap+0xe0a/0x1300 mm/mmap.c:573
vm_mmap_pgoff+0x272/0x4e0 mm/util.c:581
ksys_mmap_pgoff+0x4dc/0x760 mm/mmap.c:619
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff88807975ef00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88807975ef80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88807975f000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88807975f080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807975f100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: e9 a1 13 09 00 jmp 0x913a6
5: 48 c7 c7 90 39 9a 96 mov $0xffffffff969a3990,%rdi
c: 89 c6 mov %eax,%esi
e: e8 a3 66 42 0a call 0xa4266b6
13: e9 66 fe ff ff jmp 0xfffffe7e
18: e8 39 96 3f 0a call 0xa3f9656
1d: 41 f7 c7 00 02 00 00 test $0x200,%r15d
24: 74 b4 je 0xffffffda
26: fb sti
27: 40 84 ed test %bpl,%bpl
* 2a: 75 b3 jne 0xffffffdf <-- trapping instruction
2c: eb c4 jmp 0xfffffff2
2e: 90 nop
2f: 0f 0b ud2
31: 90 nop
32: e9 27 ff ff ff jmp 0xffffff5e
37: 90 nop
38: 0f 0b ud2
3a: 90 nop
3b: e9 2f ff ff ff jmp 0xffffff6f