==================================================================
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 ffff888036d15010 by task syz-executor/5600

CPU: 0 UID: 0 PID: 5600 Comm: syz-executor 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+0x198/0x5f0 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+0x1e6/0x9d0 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0x194/0x210 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+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:unwind_next_frame+0x1507/0x2090 arch/x86/kernel/unwind_orc.c:677
Code: 00 fc ff df 48 8d 79 02 48 89 f8 48 c1 e8 03 0f b6 34 10 48 8d 41 03 49 89 c0 49 c1 e8 03 41 0f b6 14 10 49 89 f8 41 83 e0 07 <44> 38 c6 41 0f 9e c0 40 84 f6 40 0f 95 c6 41 84 f0 0f 85 a7 07 00
RSP: 0018:ffffc90003897300 EFLAGS: 00000202
RAX: ffffffff91f5d5db RBX: 0000000000000001 RCX: ffffffff91f5d5d8
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff91f5d5da
RBP: ffffc900038973b8 R08: 0000000000000002 R09: 0000000000000007
R10: 0000000000000200 R11: 000000000001709d R12: ffffc900038973c0
R13: ffffc90003897370 R14: ffffc900038976b0 R15: ffffc900038973a4
 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 save_stack+0x162/0x1e0 mm/page_owner.c:183
 __reset_page_owner+0x84/0x190 mm/page_owner.c:338
 reset_page_owner include/linux/page_owner.h:26 [inline]
 __free_pages_prepare mm/page_alloc.c:1418 [inline]
 free_unref_folios+0xa4a/0x1790 mm/page_alloc.c:3022
 folios_put_refs+0x585/0xaa0 mm/folio.c:1034
 folio_batch_release include/linux/folio_batch.h:101 [inline]
 shmem_undo_range+0x5e5/0x1570 mm/shmem.c:1161
 shmem_truncate_range mm/shmem.c:1289 [inline]
 shmem_evict_inode+0x3b1/0xca0 mm/shmem.c:1420
 evict+0x3c2/0xad0 fs/inode.c:822
 iput_final fs/inode.c:2015 [inline]
 iput.part.0+0x989/0x1050 fs/inode.c:2064
 iput+0x35/0x40 fs/inode.c:2030
 filename_unlinkat+0x466/0x730 fs/namei.c:5723
 __do_sys_unlink fs/namei.c:5754 [inline]
 __se_sys_unlink fs/namei.c:5751 [inline]
 __x64_sys_unlink+0x46/0x70 fs/namei.c:5751
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2a8799d247
Code: 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffff05e3eb8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2a8799d247
RDX: 00007ffff05e3ee0 RSI: 00007ffff05e3f70 RDI: 00007ffff05e3f70
RBP: 00007ffff05e3f70 R08: 00007ffff05e4f70 R09: 00000000ffffffff
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffff05e5000
R13: 00007f2a87a34474 R14: 000000000004c01e R15: 00007ffff05e5040
 </TASK>

Allocated by task 7996:
 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+0x2f8/0x6d0 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+0x120/0x3b0 net/llc/llc_core.c:96
 llc_ui_autobind.isra.0+0x2ae/0x580 net/llc/af_llc.c:301
 llc_ui_connect+0x582/0xdb0 net/llc/af_llc.c:498
 connect_socket net/socket.c:2141 [inline]
 connect_socket net/socket.c:2131 [inline]
 __sys_connect_file+0x146/0x1a0 net/socket.c:2166
 __sys_connect+0x141/0x170 net/socket.c:2183
 __do_sys_connect net/socket.c:2189 [inline]
 __se_sys_connect net/socket.c:2186 [inline]
 __x64_sys_connect+0x72/0xb0 net/socket.c:2186
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5598:
 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:2748 [inline]
 __rcu_free_sheaf_prepare+0x5d/0x300 mm/slub.c:3009
 rcu_free_sheaf+0x1a/0xe0 mm/slub.c:6052
 rcu_do_batch kernel/rcu/tree.c:2650 [inline]
 rcu_core+0x5f0/0x1260 kernel/rcu/tree.c:2919
 handle_softirqs+0x1e6/0x9d0 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0x194/0x210 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+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 ffff888036d15000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 16 bytes inside of
 freed 2048-byte region [ffff888036d15000, ffff888036d15800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x36d10
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801c02f000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801c02f000 dead000000000100 dead000000000122
head: 0000000000000000 0000000000080008 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 1, tgid 1 (swapper/0), ts 17743280539
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871
 prep_new_page mm/page_alloc.c:1879 [inline]
 get_page_from_freelist+0x110d/0x35d0 mm/page_alloc.c:3943
 __alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436
 alloc_slab_page mm/slub.c:3347 [inline]
 allocate_slab mm/slub.c:3462 [inline]
 new_slab+0xa9/0x6e0 mm/slub.c:3513
 refill_objects+0xe3/0x410 mm/slub.c:7410
 refill_sheaf mm/slub.c:2885 [inline]
 __pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774
 alloc_from_pcs mm/slub.c:4850 [inline]
 slab_alloc_node mm/slub.c:4984 [inline]
 __kmalloc_cache_noprof+0x4f4/0x6d0 mm/slub.c:5559
 _kmalloc_noprof include/linux/slab.h:991 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 device_create_groups_vargs+0x8a/0x270 drivers/base/core.c:4440
 device_create_with_groups+0xf4/0x130 drivers/base/core.c:4538
 misc_register+0x4a1/0x730 drivers/char/misc.c:254
 cpu_latency_qos_init+0x16/0x60 kernel/power/qos.c:521
 do_one_initcall+0x11c/0x6f0 init/main.c:1357
 do_initcall_level init/main.c:1419 [inline]
 do_initcalls init/main.c:1435 [inline]
 do_basic_setup init/main.c:1455 [inline]
 kernel_init_freeable+0x6ea/0x7b0 init/main.c:1670
 kernel_init+0x21/0x1e0 init/main.c:1560
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888036d14f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888036d14f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888036d15000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888036d15080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888036d15100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	00 fc                	add    %bh,%ah
   2:	ff                   	lcall  (bad)
   3:	df 48 8d             	fisttps -0x73(%rax)
   6:	79 02                	jns    0xa
   8:	48 89 f8             	mov    %rdi,%rax
   b:	48 c1 e8 03          	shr    $0x3,%rax
   f:	0f b6 34 10          	movzbl (%rax,%rdx,1),%esi
  13:	48 8d 41 03          	lea    0x3(%rcx),%rax
  17:	49 89 c0             	mov    %rax,%r8
  1a:	49 c1 e8 03          	shr    $0x3,%r8
  1e:	41 0f b6 14 10       	movzbl (%r8,%rdx,1),%edx
  23:	49 89 f8             	mov    %rdi,%r8
  26:	41 83 e0 07          	and    $0x7,%r8d
* 2a:	44 38 c6             	cmp    %r8b,%sil <-- trapping instruction
  2d:	41 0f 9e c0          	setle  %r8b
  31:	40 84 f6             	test   %sil,%sil
  34:	40 0f 95 c6          	setne  %sil
  38:	41 84 f0             	test   %sil,%r8b
  3b:	0f                   	.byte 0xf
  3c:	85                   	.byte 0x85
  3d:	a7                   	cmpsl  %es:(%rdi),%ds:(%rsi)
  3e:	07                   	(bad)