==================================================================
BUG: KASAN: slab-use-after-free in llc_conn_ac_send_sabme_cmd_p_set_x+0x442/0x470 net/llc/llc_c_ac.c:782
Read of size 1 at addr ffff888034086010 by task swapper/1/0

CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 llc_conn_ac_send_sabme_cmd_p_set_x+0x442/0x470 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+0x3ec/0x1480 net/llc/llc_conn.c:66
 llc_process_tmr_ev net/llc/llc_c_ac.c:1442 [inline]
 llc_conn_tmr_common_cb+0x2d4/0x880 net/llc/llc_c_ac.c:1325
 call_timer_fn+0x19a/0x610 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers+0x757/0xb00 kernel/time/timer.c:2374
 __run_timer_base kernel/time/timer.c:2386 [inline]
 __run_timer_base kernel/time/timer.c:2378 [inline]
 run_timer_base+0x114/0x190 kernel/time/timer.c:2395
 run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2405
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: 06 8c 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 ae 10 00 fb f4 <e9> bc 48 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197e00 EFLAGS: 00000246
RAX: 0000000005337eb1 RBX: ffff88801eac2540 RCX: ffffffff8bbaf2d5
RDX: 0000000000000000 RSI: ffffffff8e1a55a5 RDI: ffffffff8c401580
RBP: ffffed1003d584a8 R08: 0000000000000001 R09: ffffed10170a678d
R10: ffff8880b8533c6b R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 1ffff92000032fc4 R15: dffffc0000000000
 arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
 default_idle+0x9/0x10 arch/x86/kernel/process.c:768
 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x3a7/0x5b0 kernel/sched/idle.c:355
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454
 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x158
 </TASK>

Allocated by task 17320:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x2e5/0x6c0 mm/slub.c:5489
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 _kzalloc_noprof include/linux/slab.h:1309 [inline]
 llc_sap_alloc net/llc/llc_core.c:29 [inline]
 llc_sap_open+0x120/0x3b0 net/llc/llc_core.c:96
 llc_ui_bind+0xb67/0xe40 net/llc/af_llc.c:386
 __sys_bind_socket net/socket.c:1920 [inline]
 __sys_bind_socket net/socket.c:1912 [inline]
 __sys_bind+0x1a9/0x260 net/socket.c:1951
 __do_sys_bind net/socket.c:1956 [inline]
 __se_sys_bind net/socket.c:1954 [inline]
 __x64_sys_bind+0x72/0xb0 net/socket.c:1954
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 17335:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2677 [inline]
 __rcu_free_sheaf_prepare+0x5d/0x2f0 mm/slub.c:2928
 rcu_free_sheaf+0x1a/0xe0 mm/slub.c:5978
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2897
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa3/0xc0 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 ffff888034086000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 16 bytes inside of
 freed 2048-byte region [ffff888034086000, ffff888034086800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888034084000 pfn:0x34080
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 ffff88813fe23000 ffffea0000dc0410 ffffea0001ea6410
raw: ffff888034084000 0000000800080006 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88813fe23000 ffffea0000dc0410 ffffea0001ea6410
head: ffff888034084000 0000000800080006 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5617, tgid 5617 (syz-executor), ts 66272750596, free_ts 54539560664
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3266 [inline]
 allocate_slab mm/slub.c:3380 [inline]
 new_slab+0xa2/0x640 mm/slub.c:3426
 refill_objects+0xe3/0x410 mm/slub.c:7310
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675
 alloc_from_pcs mm/slub.c:4773 [inline]
 slab_alloc_node mm/slub.c:4905 [inline]
 __do_kmalloc_node mm/slub.c:5333 [inline]
 __kmalloc_node_track_caller_noprof+0x679/0x830 mm/slub.c:5471
 kmalloc_reserve+0xe8/0x350 net/core/skbuff.c:637
 pskb_expand_head+0x249/0x10e0 net/core/skbuff.c:2306
 netlink_trim+0x22d/0x2f0 net/netlink/af_netlink.c:1300
 netlink_broadcast_filtered+0x6d/0xf20 net/netlink/af_netlink.c:1518
 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
 nlmsg_multicast include/net/netlink.h:1184 [inline]
 nlmsg_notify+0xb1/0x290 net/netlink/af_netlink.c:2599
 rtnl_notify net/core/rtnetlink.c:963 [inline]
 rtmsg_ifinfo_send net/core/rtnetlink.c:4553 [inline]
 rtmsg_ifinfo_event net/core/rtnetlink.c:4569 [inline]
 rtmsg_ifinfo_event net/core/rtnetlink.c:4556 [inline]
 rtmsg_ifinfo+0x177/0x1b0 net/core/rtnetlink.c:4575
 __dev_notify_flags+0x24c/0x2e0 net/core/dev.c:9795
 rtnl_configure_link+0x1b5/0x280 net/core/rtnetlink.c:3679
 veth_newlink+0x3af/0xa00 drivers/net/veth.c:1873
page last free pid 5568 tgid 5568 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4584 [inline]
 slab_alloc_node mm/slub.c:4917 [inline]
 kmem_cache_alloc_noprof+0x26b/0x6a0 mm/slub.c:4931
 mt_alloc_one lib/maple_tree.c:139 [inline]
 mas_alloc_nodes lib/maple_tree.c:1089 [inline]
 mas_preallocate+0x1105/0x14a0 lib/maple_tree.c:4961
 vma_iter_prealloc mm/vma.h:577 [inline]
 commit_merge+0x3e3/0xbd0 mm/vma.c:754
 vma_expand+0xac5/0xea0 mm/vma.c:1219
 relocate_vma_down+0x260/0x4e0 mm/vma_exec.c:59
 setup_arg_pages+0x6f8/0xd30 fs/exec.c:694
 load_elf_binary+0xb68/0x51c0 fs/binfmt_elf.c:1028
 search_binary_handler fs/exec.c:1694 [inline]
 exec_binprm fs/exec.c:1726 [inline]
 bprm_execve fs/exec.c:1778 [inline]
 bprm_execve+0x8fb/0x1730 fs/exec.c:1754
 do_execveat_common.isra.0+0x4a5/0x580 fs/exec.c:1876
 __do_sys_execve fs/exec.c:1949 [inline]
 __se_sys_execve fs/exec.c:1943 [inline]
 __x64_sys_execve+0x93/0xd0 fs/exec.c:1943
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888034085f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888034085f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888034086000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888034086080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888034086100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	8c 02                	mov    %es,(%rdx)
   2:	c3                   	ret
   3:	cc                   	int3
   4:	cc                   	int3
   5:	cc                   	int3
   6:	cc                   	int3
   7:	0f 1f 00             	nopl   (%rax)
   a:	90                   	nop
   b:	90                   	nop
   c:	90                   	nop
   d:	90                   	nop
   e:	90                   	nop
   f:	90                   	nop
  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:	f3 0f 1e fa          	endbr64
  1e:	66 90                	xchg   %ax,%ax
  20:	0f 00 2d c3 ae 10 00 	verw   0x10aec3(%rip)        # 0x10aeea
  27:	fb                   	sti
  28:	f4                   	hlt
* 29:	e9 bc 48 03 00       	jmp    0x348ea <-- trapping instruction
  2e:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
  35:	00 00 00
  38:	66 90                	xchg   %ax,%ax
  3a:	90                   	nop
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	90                   	nop