==================================================================
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 ffff88801eee9010 by task syz-executor/18361

CPU: 1 UID: 0 PID: 18361 Comm: syz-executor 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:
 <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+0x226/0x860 kernel/softirq.c:645
 do_softirq+0x77/0xd0 kernel/softirq.c:546
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473
 netdev_for_each_tx_queue include/linux/netdevice.h:2749 [inline]
 dev_deactivate_many+0x778/0xda0 net/sched/sch_generic.c:1394
 __dev_close_many+0x180/0x6e0 net/core/dev.c:1782
 netif_close_many+0x249/0x660 net/core/dev.c:1824
 netif_close_many_and_unlock net/core/dev.c:12411 [inline]
 unregister_netdevice_many_notify+0x843/0x2140 net/core/dev.c:12481
 unregister_netdevice_many net/core/dev.c:12589 [inline]
 unregister_netdevice_queue+0x2f5/0x340 net/core/dev.c:12390
 unregister_netdevice include/linux/netdevice.h:3487 [inline]
 nsim_destroy+0x275/0x800 drivers/net/netdevsim/netdev.c:1198
 __nsim_dev_port_del+0x14e/0x200 drivers/net/netdevsim/dev.c:1472
 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1486 [inline]
 nsim_dev_reload_destroy+0x288/0x490 drivers/net/netdevsim/dev.c:1710
 nsim_drv_remove+0x58/0x170 drivers/net/netdevsim/dev.c:1725
 device_remove drivers/base/dd.c:616 [inline]
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x48b/0x880 drivers/base/dd.c:1372
 bus_remove_device+0x444/0x560 drivers/base/bus.c:664
 device_del+0x524/0x8f0 drivers/base/core.c:3965
 device_unregister+0x21/0xf0 drivers/base/core.c:4006
 nsim_bus_dev_del drivers/net/netdevsim/bus.c:488 [inline]
 del_device_store+0x2b5/0x370 drivers/net/netdevsim/bus.c:244
 kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x612/0xba0 fs/read_write.c:687
 ksys_write+0x150/0x270 fs/read_write.c:739
 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: 0033:0x7f154335e98e
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:00007ffd5eb4acf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000055556f473500 RCX: 00007f154335e98e
RDX: 0000000000000001 RSI: 00007ffd5eb4ad80 RDI: 0000000000000005
RBP: 00007f15434358be R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffd5eb4ad80 R14: 00007f1544154620 R15: 0000000000000003
 </TASK>

Allocated by task 18728:
 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 18730:
 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:6060
 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: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
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674

The buggy address belongs to the object at ffff88801eee9000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 16 bytes inside of
 freed 2048-byte region [ffff88801eee9000, ffff88801eee9800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1eee8
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 5612, tgid 5612 (syz-executor), ts 92454546046
 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:7417
 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]
 __kmalloc_cache_noprof+0x39b/0x600 mm/slub.c:5559
 _kmalloc_noprof include/linux/slab.h:991 [inline]
 rtnl_newlink+0x143/0x1c30 net/core/rtnetlink.c:4118
 rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7137
 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
 __sock_sendmsg net/socket.c:815 [inline]
 __sys_sendto+0x408/0x5a0 net/socket.c:2281
 __do_sys_sendto net/socket.c:2288 [inline]
 __se_sys_sendto net/socket.c:2284 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2284
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
page last free pid 5610 tgid 5610 ts 92405953116 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:5823
 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_lru_noprof+0x2a3/0x5f0 mm/slub.c:5029
 __d_alloc+0x37/0x6f0 fs/dcache.c:1907
 d_alloc+0x4b/0x190 fs/dcache.c:1986
 lookup_one_qstr_excl+0xd8/0x360 fs/namei.c:1806
 __start_dirop fs/namei.c:2920 [inline]
 start_dirop+0x5c/0x90 fs/namei.c:2942
 simple_start_creating+0xcc/0x110 fs/libfs.c:2308
 debugfs_start_creating+0xca/0x1b0 fs/debugfs/inode.c:397
 __debugfs_create_file+0x6f/0x400 fs/debugfs/inode.c:431
 debugfs_create_file_full+0x3f/0x60 fs/debugfs/inode.c:463
 nsim_psp_init+0xf5/0x130 drivers/net/netdevsim/psp.c:286
 nsim_init_netdevsim drivers/net/netdevsim/netdev.c:1077 [inline]
 nsim_create+0xc33/0x1150 drivers/net/netdevsim/netdev.c:1154

Memory state around the buggy address:
 ffff88801eee8f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88801eee8f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88801eee9000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88801eee9080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801eee9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================