syzbot

==================================================================
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 ffff888034e5a010 by task kworker/u8:6/1025

CPU: 1 UID: 0 PID: 1025 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026
Workqueue: iou_exit io_ring_exit_work
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:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:188 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:206
Code: 90 f3 0f 1e fa 53 48 8b 74 24 08 48 89 fb 48 83 c7 18 e8 ba a0 28 f6 48 89 df e8 42 f0 28 f6 e8 2d 54 55 f6 fb bf 01 00 00 00 <e8> 12 00 18 f6 65 8b 05 5b b9 a6 08 85 c0 74 06 5b e9 81 4a 00 00
RSP: 0018:ffffc90005627930 EFLAGS: 00000202
RAX: 00000000000b140b RBX: ffff88804dc64380 RCX: 0000000000000040
RDX: 0000000000000000 RSI: ffffffff8e1a4788 RDI: 0000000000000001
RBP: 1ffff92000ac4f2a R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888059134c98
R13: ffff88804dc643c0 R14: ffff888059cf6d00 R15: ffff88804dc643c0
 io_timeout_complete+0x3a6/0x450 io_uring/timeout.c:123
 io_cancel_local_task_work+0x263/0x350 io_uring/tw.c:268
 io_ring_exit_work+0x249/0xd7a io_uring/io_uring.c:2347
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 6734:
 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:5515
 _kmalloc_noprof include/linux/slab.h:969 [inline]
 _kzalloc_noprof include/linux/slab.h:1290 [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
 __sys_connect_file+0x141/0x1a0 net/socket.c:2135
 __sys_connect+0x141/0x170 net/socket.c:2154
 __do_sys_connect net/socket.c:2160 [inline]
 __se_sys_connect net/socket.c:2157 [inline]
 __x64_sys_connect+0x72/0xb0 net/socket.c:2157
 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 6260:
 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:2705 [inline]
 __rcu_free_sheaf_prepare+0x5d/0x2f0 mm/slub.c:2956
 rcu_free_sheaf+0x1a/0xe0 mm/slub.c:6004
 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 ffff888034e5a000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 16 bytes inside of
 freed 2048-byte region [ffff888034e5a000, ffff888034e5a800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888034e59000 pfn:0x34e58
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 ffff88813fe22000 ffffea00006f6810 ffffea000081a010
raw: ffff888034e59000 0000000800080005 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88813fe22000 ffffea00006f6810 ffffea000081a010
head: ffff888034e59000 0000000800080005 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 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1042, tgid 1042 (kworker/u8:7), ts 66432918072, free_ts 42938458107
 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:3294 [inline]
 allocate_slab mm/slub.c:3408 [inline]
 new_slab+0xa2/0x650 mm/slub.c:3454
 refill_objects+0xe3/0x410 mm/slub.c:7338
 refill_sheaf mm/slub.c:2832 [inline]
 __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4703
 alloc_from_pcs mm/slub.c:4801 [inline]
 slab_alloc_node mm/slub.c:4933 [inline]
 __do_kmalloc_node mm/slub.c:5361 [inline]
 __kmalloc_node_track_caller_noprof+0x679/0x830 mm/slub.c:5497
 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
 netif_state_change+0x17f/0x380 net/core/dev.c:1605
 linkwatch_do_dev net/core/link_watch.c:186 [inline]
 linkwatch_do_dev+0xe0/0x120 net/core/link_watch.c:166
 __linkwatch_run_queue+0x3a9/0x900 net/core/link_watch.c:240
page last free pid 5361 tgid 5361 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:4612 [inline]
 slab_alloc_node mm/slub.c:4945 [inline]
 kmem_cache_alloc_noprof+0x26b/0x6a0 mm/slub.c:4959
 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
 vma_merge_new_range+0x516/0xc00 mm/vma.c:1112
 __mmap_region+0xa86/0x2db0 mm/vma.c:2769
 mmap_region+0x35d/0x620 mm/vma.c:2860
 do_mmap+0xc63/0x12f0 mm/mmap.c:560
 vm_mmap_pgoff+0x29e/0x470 mm/util.c:581
 ksys_mmap_pgoff+0xe4/0x610 mm/mmap.c:606
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline]
 __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94

Memory state around the buggy address:
 ffff888034e59f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888034e59f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888034e5a000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888034e5a080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888034e5a100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	90                   	nop
   1:	f3 0f 1e fa          	endbr64
   5:	53                   	push   %rbx
   6:	48 8b 74 24 08       	mov    0x8(%rsp),%rsi
   b:	48 89 fb             	mov    %rdi,%rbx
   e:	48 83 c7 18          	add    $0x18,%rdi
  12:	e8 ba a0 28 f6       	call   0xf628a0d1
  17:	48 89 df             	mov    %rbx,%rdi
  1a:	e8 42 f0 28 f6       	call   0xf628f061
  1f:	e8 2d 54 55 f6       	call   0xf6555451
  24:	fb                   	sti
  25:	bf 01 00 00 00       	mov    $0x1,%edi
* 2a:	e8 12 00 18 f6       	call   0xf6180041 <-- trapping instruction
  2f:	65 8b 05 5b b9 a6 08 	mov    %gs:0x8a6b95b(%rip),%eax        # 0x8a6b991
  36:	85 c0                	test   %eax,%eax
  38:	74 06                	je     0x40
  3a:	5b                   	pop    %rbx
  3b:	e9 81 4a 00 00       	jmp    0x4ac1