==================================================================
BUG: KASAN: use-after-free in llc_conn_ac_send_sabme_cmd_p_set_x+0x332/0x3c0 net/llc/llc_c_ac.c:788
Read of size 1 at addr ffff888060420010 by task syz-executor/4708

CPU: 0 PID: 4708 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 llc_conn_ac_send_sabme_cmd_p_set_x+0x332/0x3c0 net/llc/llc_c_ac.c:788
 llc_exec_conn_trans_actions net/llc/llc_conn.c:442 [inline]
 llc_conn_service net/llc/llc_conn.c:367 [inline]
 llc_conn_state_process+0x506/0x12b0 net/llc/llc_conn.c:71
 llc_process_tmr_ev net/llc/llc_c_ac.c:1445 [inline]
 llc_conn_tmr_common_cb+0x336/0x7e0 net/llc/llc_c_ac.c:1331
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x56c/0x810 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x336/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:console_unlock+0xc90/0x10f0 kernel/printk/printk.c:2749
Code: 75 11 e8 e3 e3 18 00 4d 85 e4 75 16 e8 d9 e3 18 00 eb 15 e8 d2 e3 18 00 e8 dd f6 5f 08 4d 85 e4 74 ea e8 c3 e3 18 00 fb 31 ff <89> de e8 19 e7 18 00 85 db 0f 94 c0 22 44 24 1f 3c 01 75 1f e8 a7
RSP: 0018:ffffc9000319ec80 EFLAGS: 00000246
RAX: ffffffff81601dbd RBX: 0000000000000000 RCX: ffff88807a060000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000319eef0 R08: ffffffff901ee0c7 R09: 1ffffffff203dc18
R10: dffffc0000000000 R11: fffffbfff203dc19 R12: 0000000000000200
R13: 000000000000004b R14: 0000000000000000 R15: dffffc0000000000
 vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
 _printk+0xda/0x130 kernel/printk/printk.c:2299
 caif_netlink_parms net/caif/chnl_net.c:425 [inline]
 ipcaif_newlink+0x1e1/0x4c0 net/caif/chnl_net.c:450
 __rtnl_newlink net/core/rtnetlink.c:3538 [inline]
 rtnl_newlink+0x139e/0x1920 net/core/rtnetlink.c:3586
 rtnetlink_rcv_msg+0x7f1/0xf10 net/core/rtnetlink.c:5698
 netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2519
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x78f/0x940 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 __sys_sendto+0x46d/0x620 net/socket.c:2073
 __do_sys_sendto net/socket.c:2085 [inline]
 __se_sys_sendto net/socket.c:2081 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2081
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f403f9126ce
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 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffe7c16a788 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000555569e95500 RCX: 00007f403f9126ce
RDX: 0000000000000048 RSI: 00007f4040708670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffe7c16a804 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f4040708670 R15: 0000000000000000
 </TASK>

Allocated by task 4723:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc+0xaf/0xe0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:607 [inline]
 kzalloc include/linux/slab.h:738 [inline]
 llc_sap_alloc net/llc/llc_core.c:35 [inline]
 llc_sap_open+0xda/0x330 net/llc/llc_core.c:102
 llc_ui_autobind+0x1fa/0x4b0 net/llc/af_llc.c:306
 llc_ui_connect+0x1c5/0xc70 net/llc/af_llc.c:501
 __sys_connect_file net/socket.c:1933 [inline]
 __sys_connect+0x3cb/0x450 net/socket.c:1950
 __do_sys_connect net/socket.c:1960 [inline]
 __se_sys_connect net/socket.c:1957 [inline]
 __x64_sys_connect+0x76/0x80 net/socket.c:1957
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 4228:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xec/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kmem_cache_free_bulk+0x38b/0x490 mm/slub.c:3645
 kfree_bulk include/linux/slab.h:465 [inline]
 kfree_rcu_work+0x311/0x900 kernel/rcu/tree.c:3299
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Last potentially related work creation:
 kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
 kvfree_call_rcu+0x105/0x7f0 kernel/rcu/tree.c:3600
 llc_sap_put include/net/llc.h:132 [inline]
 llc_ui_release+0x212/0x450 net/llc/af_llc.c:223
 __sock_release net/socket.c:651 [inline]
 sock_close+0xbf/0x210 net/socket.c:1346
 __fput+0x212/0x8c0 fs/file_table.c:311
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 get_signal+0x123e/0x12e0 kernel/signal.c:2673
 arch_do_signal_or_restart+0xe6/0x12a0 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Second to last potentially related work creation:
 kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
 __call_rcu kernel/rcu/tree.c:3011 [inline]
 call_rcu+0x189/0x900 kernel/rcu/tree.c:3091
 netlink_release+0x134c/0x1790 net/netlink/af_netlink.c:795
 __sock_release net/socket.c:651 [inline]
 sock_close+0xbf/0x210 net/socket.c:1346
 __fput+0x212/0x8c0 fs/file_table.c:311
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff888060420000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 16 bytes inside of
 2048-byte region [ffff888060420000, ffff888060420800)
The buggy address belongs to the page:
page:ffffea0001810800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x60420
head:ffffea0001810800 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888016c42000
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
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 4187, ts 62634774416, free_ts 22440958518
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
 alloc_slab_page mm/slub.c:1780 [inline]
 allocate_slab mm/slub.c:1917 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1980
 ___slab_alloc+0x807/0xdd0 mm/slub.c:3013
 __slab_alloc mm/slub.c:3100 [inline]
 slab_alloc_node mm/slub.c:3191 [inline]
 slab_alloc mm/slub.c:3233 [inline]
 __kmalloc+0x11d/0x340 mm/slub.c:4408
 kmalloc include/linux/slab.h:612 [inline]
 sk_prot_alloc+0xe7/0x210 net/core/sock.c:1866
 sk_alloc+0x2f/0x310 net/core/sock.c:1922
 __netlink_create+0x6c/0x290 net/netlink/af_netlink.c:629
 netlink_create+0x3a7/0x510 net/netlink/af_netlink.c:688
 __sock_create+0x473/0x910 net/socket.c:1496
 sock_create net/socket.c:1552 [inline]
 __sys_socket+0xe2/0x170 net/socket.c:1594
 __do_sys_socket net/socket.c:1603 [inline]
 __se_sys_socket net/socket.c:1601 [inline]
 __x64_sys_socket+0x76/0x80 net/socket.c:1601
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396
 free_contig_range+0x96/0xf0 mm/page_alloc.c:9428
 destroy_args+0xef/0xa00 mm/debug_vm_pgtable.c:1018
 debug_vm_pgtable+0x321/0x380 mm/debug_vm_pgtable.c:1336
 do_one_initcall+0x272/0x730 init/main.c:1315
 do_initcall_level+0x13d/0x1f0 init/main.c:1388
 do_initcalls+0x4b/0x90 init/main.c:1404
 kernel_init_freeable+0x3d5/0x560 init/main.c:1628
 kernel_init+0x19/0x1b0 init/main.c:1519
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Memory state around the buggy address:
 ffff88806041ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88806041ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888060420000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888060420080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888060420100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	75 11                	jne    0x13
   2:	e8 e3 e3 18 00       	call   0x18e3ea
   7:	4d 85 e4             	test   %r12,%r12
   a:	75 16                	jne    0x22
   c:	e8 d9 e3 18 00       	call   0x18e3ea
  11:	eb 15                	jmp    0x28
  13:	e8 d2 e3 18 00       	call   0x18e3ea
  18:	e8 dd f6 5f 08       	call   0x85ff6fa
  1d:	4d 85 e4             	test   %r12,%r12
  20:	74 ea                	je     0xc
  22:	e8 c3 e3 18 00       	call   0x18e3ea
  27:	fb                   	sti
  28:	31 ff                	xor    %edi,%edi
* 2a:	89 de                	mov    %ebx,%esi <-- trapping instruction
  2c:	e8 19 e7 18 00       	call   0x18e74a
  31:	85 db                	test   %ebx,%ebx
  33:	0f 94 c0             	sete   %al
  36:	22 44 24 1f          	and    0x1f(%rsp),%al
  3a:	3c 01                	cmp    $0x1,%al
  3c:	75 1f                	jne    0x5d
  3e:	e8                   	.byte 0xe8
  3f:	a7                   	cmpsl  %es:(%rdi),%ds:(%rsi)