==================================================================
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 ffff888029dce010 by task udevd/5641

CPU: 0 UID: 0 PID: 5641 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <IRQ>
 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+0x223/0x840 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:758
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:775
 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
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:find_stack lib/stackdepot.c:609 [inline]
RIP: 0010:stack_depot_save_flags+0x159/0x7f0 lib/stackdepot.c:676
Code: 31 c5 c1 c0 18 29 c5 48 8b 05 23 dc b4 15 8b 0d 15 dc b4 15 21 e9 48 c1 e1 04 4c 8d 24 08 65 48 ff 05 cb e7 76 0e 4c 8b 3c 08 <4d> 39 e7 74 0a 44 88 6c 24 08 45 89 d5 eb 34 45 31 ff e9 87 00 00
RSP: 0018:ffffc90004ac7918 EFLAGS: 00000282
RAX: ffff88823ae00000 RBX: 0000000000000d40 RCX: 0000000000418bd0
RDX: 00000000ca4057f2 RSI: 0000000000000001 RDI: 00000000109bc825
RBP: 00000000cda418bd R08: 0000000033490ee4 R09: 00000000fa1c87b2
R10: 000000000000000a R11: ffffffff81b3b390 R12: ffff88823b218bd0
R13: ffff88807eb6dd01 R14: ffffc90004ac7970 R15: ffff88807f6a19b0
 kasan_save_stack mm/kasan/common.c:58 [inline]
 kasan_save_track+0x4f/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:409 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5531 [inline]
 __kmalloc_noprof+0x366/0x710 mm/slub.c:5556
 _kmalloc_noprof include/linux/slab.h:995 [inline]
 _kmalloc_array_noprof include/linux/slab.h:1211 [inline]
 security_inode_init_security+0x102/0x3e0 security/security.c:1386
 shmem_symlink+0xe0/0x4d0 mm/shmem.c:4269
 vfs_symlink+0x18e/0x330 fs/namei.c:5807
 filename_symlinkat+0x1cd/0x410 fs/namei.c:5832
 __do_sys_symlink fs/namei.c:5859 [inline]
 __se_sys_symlink+0x4d/0x2b0 fs/namei.c:5855
 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
RIP: 0033:0x7fd4aa915527
Code: f0 ff ff 77 06 c3 0f 1f 44 00 00 48 8b 15 c9 b8 0d 00 f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 b8 58 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 a1 b8 0d 00 f7 d8 64 89 02 b8
RSP: 002b:00007ffca81ef688 EFLAGS: 00000202 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 000055b4c669a410 RCX: 00007fd4aa915527
RDX: fffffffffffffe68 RSI: 00007ffca81ef690 RDI: 000055b4c66751c0
RBP: 00000000000000cd R08: 0000000000000064 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffca81ef690
R13: 000055b4c6666190 R14: 0000000000000008 R15: 000055b4c669a410
 </TASK>

Allocated by task 6311:
 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:409 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x31c/0x600 mm/slub.c:5680
 _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+0x1dc/0xe40 net/llc/af_llc.c:498
 connect_socket net/socket.c:2143 [inline]
 __sys_connect_file net/socket.c:2168 [inline]
 __sys_connect+0x316/0x450 net/socket.c:2185
 __do_sys_connect net/socket.c:2191 [inline]
 __se_sys_connect net/socket.c:2188 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2188
 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 203:
 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:264 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:296
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2780 [inline]
 __rcu_free_sheaf_prepare+0x12d/0x2a0 mm/slub.c:3041
 rcu_free_sheaf+0x31/0x200 mm/slub.c:6182
 rcu_do_batch kernel/rcu/tree.c:2650 [inline]
 rcu_core+0x926/0x1260 kernel/rcu/tree.c:2919
 handle_softirqs+0x223/0x840 kernel/softirq.c:645
 do_softirq+0x77/0xd0 kernel/softirq.c:546
 __local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473
 spin_unlock_bh include/linux/spinlock.h:407 [inline]
 batadv_tt_global_purge net/batman-adv/translation-table.c:2709 [inline]
 batadv_tt_purge+0x4ee/0xa40 net/batman-adv/translation-table.c:4099
 process_one_work kernel/workqueue.c:3495 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
 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

The buggy address belongs to the object at ffff888029dce000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 16 bytes inside of
 freed 2048-byte region [ffff888029dce000, ffff888029dce800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x29dc8
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 ffff88801b042000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b042000 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 9, tgid 9 (kworker/0:0), ts 83322771182
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1854
 prep_new_page mm/page_alloc.c:1862 [inline]
 get_page_from_freelist+0x220f/0x2280 mm/page_alloc.c:3933
 __alloc_frozen_pages_noprof+0x1fc/0x400 mm/page_alloc.c:5468
 alloc_slab_page mm/slub.c:3384 [inline]
 allocate_slab+0x7d/0x5e0 mm/slub.c:3499
 new_slab mm/slub.c:3550 [inline]
 refill_objects+0x2d5/0x350 mm/slub.c:7539
 refill_sheaf mm/slub.c:2917 [inline]
 __pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4811
 alloc_from_pcs mm/slub.c:4887 [inline]
 slab_alloc_node mm/slub.c:5021 [inline]
 __do_kmalloc_node mm/slub.c:5530 [inline]
 __kmalloc_node_track_caller_noprof+0x543/0x720 mm/slub.c:5662
 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:1810
 add_grhead net/ipv6/mcast.c:1921 [inline]
 add_grec+0x119f/0x19d0 net/ipv6/mcast.c:2060
 mld_send_cr net/ipv6/mcast.c:2185 [inline]
 mld_ifc_work+0x6f1/0xd60 net/ipv6/mcast.c:2739
 process_one_work kernel/workqueue.c:3495 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
 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 5799 tgid 5799 ts 83213326516 stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 __free_pages_prepare mm/page_alloc.c:1401 [inline]
 __free_frozen_pages+0xc97/0xd90 mm/page_alloc.c:2952
 __slab_free+0x269/0x2c0 mm/slub.c:5926
 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:361
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4720 [inline]
 slab_alloc_node mm/slub.c:5033 [inline]
 kmem_cache_alloc_noprof+0x2b4/0x600 mm/slub.c:5047
 ptlock_alloc+0x20/0x70 mm/memory.c:7756
 ptlock_init include/linux/mm.h:4067 [inline]
 pagetable_pte_ctor include/linux/mm.h:4116 [inline]
 __pte_alloc_one_noprof include/asm-generic/pgalloc.h:79 [inline]
 pte_alloc_one+0x7a/0x370 arch/x86/mm/pgtable.c:18
 __do_fault+0xd1/0x2a0 mm/memory.c:5628
 do_cow_fault mm/memory.c:6098 [inline]
 do_fault mm/memory.c:6204 [inline]
 do_pte_missing+0xfc9/0x3570 mm/memory.c:4762
 handle_pte_fault mm/memory.c:6626 [inline]
 __handle_mm_fault mm/memory.c:6775 [inline]
 handle_mm_fault+0x1a53/0x3750 mm/memory.c:6942
 do_user_addr_fault+0x7f6/0x1480 arch/x86/mm/fault.c:1394
 handle_page_fault arch/x86/mm/fault.c:1483 [inline]
 exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1536
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595

Memory state around the buggy address:
 ffff888029dcdf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888029dcdf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888029dce000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888029dce080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888029dce100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	31 c5                	xor    %eax,%ebp
   2:	c1 c0 18             	rol    $0x18,%eax
   5:	29 c5                	sub    %eax,%ebp
   7:	48 8b 05 23 dc b4 15 	mov    0x15b4dc23(%rip),%rax        # 0x15b4dc31
   e:	8b 0d 15 dc b4 15    	mov    0x15b4dc15(%rip),%ecx        # 0x15b4dc29
  14:	21 e9                	and    %ebp,%ecx
  16:	48 c1 e1 04          	shl    $0x4,%rcx
  1a:	4c 8d 24 08          	lea    (%rax,%rcx,1),%r12
  1e:	65 48 ff 05 cb e7 76 	incq   %gs:0xe76e7cb(%rip)        # 0xe76e7f1
  25:	0e
  26:	4c 8b 3c 08          	mov    (%rax,%rcx,1),%r15
* 2a:	4d 39 e7             	cmp    %r12,%r15 <-- trapping instruction
  2d:	74 0a                	je     0x39
  2f:	44 88 6c 24 08       	mov    %r13b,0x8(%rsp)
  34:	45 89 d5             	mov    %r10d,%r13d
  37:	eb 34                	jmp    0x6d
  39:	45 31 ff             	xor    %r15d,%r15d
  3c:	e9                   	.byte 0xe9
  3d:	87 00                	xchg   %eax,(%rax)