==================================================================
BUG: KASAN: slab-use-after-free in __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:166
Read of size 1 at addr ffff88806d6d4418 by task kworker/u33:31/21543

CPU: 0 UID: 0 PID: 21543 Comm: kworker/u33:31 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: events_unbound cfg80211_wiphy_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
 __kasan_check_byte+0x36/0x50 mm/kasan/common.c:574
 kasan_check_byte include/linux/kasan.h:402 [inline]
 lock_acquire kernel/locking/lockdep.c:5842 [inline]
 lock_acquire+0x132/0x370 kernel/locking/lockdep.c:5825
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
 _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:166
 p9_tag_remove net/9p/client.c:274 [inline]
 p9_req_put net/9p/client.c:282 [inline]
 p9_req_put+0xaf/0x250 net/9p/client.c:279
 req_done+0x1dc/0x2e0 net/9p/trans_virtio.c:147
 vring_interrupt+0x2ef/0x660 drivers/virtio/virtio_ring.c:3297
 __handle_irq_event_percpu+0x232/0x880 kernel/irq/handle.c:209
 handle_irq_event_percpu kernel/irq/handle.c:246 [inline]
 handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:263
 handle_edge_irq+0x34c/0x950 kernel/irq/chip.c:859
 generic_handle_irq_desc include/linux/irqdesc.h:188 [inline]
 handle_irq arch/x86/kernel/irq.c:209 [inline]
 call_irq_handler arch/x86/kernel/irq.c:265 [inline]
 __common_interrupt+0xd8/0x2f0 arch/x86/kernel/irq.c:280
 common_interrupt+0x60/0xe0 arch/x86/kernel/irq.c:273
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:665
RIP: 0010:handle_softirqs+0x1ad/0x9b0 kernel/softirq.c:608
Code: 20 44 88 74 24 1e 45 89 ee 48 c7 c7 c0 7a cd 8b e8 f8 f6 ef 09 31 d2 65 66 89 15 b6 4b 9b 12 e8 69 75 49 00 fb bb ff ff ff ff <49> c7 c4 c0 a0 80 8e 41 0f bc de 83 c3 01 0f 85 a4 00 00 00 e9 1b
RSP: 0000:ffffc90000007f28 EFLAGS: 00000202
RAX: 000000000006943e RBX: 00000000ffffffff RCX: 0000000000000004
RDX: 0000000000000000 RSI: ffffffff8e1a87c3 RDI: ffffffff8c400a80
RBP: 0000000100016836 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 000000000000000a
R13: 0000000000000302 R14: 0000000000000302 R15: 1ffff92000000fec
 __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_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 76 07 2a f6 48 89 df e8 fe 56 2a f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 <bf> 01 00 00 00 e8 d5 66 19 f6 65 8b 05 4e 77 a8 08 85 c0 74 16 5b
RSP: 0000:ffffc90003adf788 EFLAGS: 00000246
RAX: 0000000000000002 RBX: ffffffff9b9381c8 RCX: 0000000000000040
RDX: 0000000000000000 RSI: ffffffff8e1a87c3 RDI: ffffffff8c400a80
RBP: 0000000000000206 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003
R13: ffff888067ff9d28 R14: ffffffff8bd2e260 R15: 1ffff9200075bef8
 debug_object_assert_init+0x1c4/0x310 lib/debugobjects.c:1072
 debug_timer_assert_init kernel/time/timer.c:803 [inline]
 debug_assert_init kernel/time/timer.c:848 [inline]
 __mod_timer+0xad/0xca0 kernel/time/timer.c:1025
 ieee80211_sta_merge_ibss net/mac80211/ibss.c:1234 [inline]
 ieee80211_ibss_work+0x46d/0x1050 net/mac80211/ibss.c:1638
 ieee80211_iface_work+0xac4/0x1070 net/mac80211/iface.c:1845
 cfg80211_wiphy_work+0x2b7/0x550 net/wireless/core.c:538
 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 24320:
 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]
 p9_client_create+0xaf/0xd40 net/9p/client.c:864
 v9fs_session_init+0x3c/0xdd0 fs/9p/v9fs.c:471
 v9fs_get_tree+0xb8/0xb50 fs/9p/vfs_super.c:97
 vfs_get_tree+0x92/0x320 fs/super.c:1700
 fc_mount fs/namespace.c:1198 [inline]
 do_new_mount_fc fs/namespace.c:3765 [inline]
 do_new_mount fs/namespace.c:3841 [inline]
 path_mount+0x7d0/0x23d0 fs/namespace.c:4161
 do_mount fs/namespace.c:4174 [inline]
 __do_sys_mount fs/namespace.c:4390 [inline]
 __se_sys_mount fs/namespace.c:4367 [inline]
 __ia32_sys_mount+0x292/0x310 fs/namespace.c:4367
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xe7/0x970 arch/x86/entry/syscall_32.c:307
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Freed by task 24320:
 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]
 slab_free mm/slub.c:6377 [inline]
 kfree+0x22b/0x6c0 mm/slub.c:6692
 p9_client_create+0x72d/0xd40 net/9p/client.c:943
 v9fs_session_init+0x3c/0xdd0 fs/9p/v9fs.c:471
 v9fs_get_tree+0xb8/0xb50 fs/9p/vfs_super.c:97
 vfs_get_tree+0x92/0x320 fs/super.c:1700
 fc_mount fs/namespace.c:1198 [inline]
 do_new_mount_fc fs/namespace.c:3765 [inline]
 do_new_mount fs/namespace.c:3841 [inline]
 path_mount+0x7d0/0x23d0 fs/namespace.c:4161
 do_mount fs/namespace.c:4174 [inline]
 __do_sys_mount fs/namespace.c:4390 [inline]
 __se_sys_mount fs/namespace.c:4367 [inline]
 __ia32_sys_mount+0x292/0x310 fs/namespace.c:4367
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xe7/0x970 arch/x86/entry/syscall_32.c:307
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

The buggy address belongs to the object at ffff88806d6d4400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 24 bytes inside of
 freed 512-byte region [ffff88806d6d4400, ffff88806d6d4600)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6d6d4
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000040 ffff88801bc42c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 04fff00000000040 ffff88801bc42c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 04fff00000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 22536, tgid 22536 (syz-executor), ts 1107677929872, free_ts 1100914771307
 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_noprof+0x66d/0x820 mm/slub.c:5359
 _kmalloc_noprof include/linux/slab.h:992 [inline]
 _kzalloc_noprof include/linux/slab.h:1309 [inline]
 fib6_info_alloc+0x40/0x160 net/ipv6/ip6_fib.c:155
 ip6_route_info_create+0x14c/0xad0 net/ipv6/route.c:3833
 ip6_route_add+0x4b/0x1d0 net/ipv6/route.c:3962
 addrconf_add_mroute+0x1de/0x350 net/ipv6/addrconf.c:2568
 addrconf_add_dev+0x14e/0x1a0 net/ipv6/addrconf.c:2586
 inet6_addr_add+0xfc/0x9a0 net/ipv6/addrconf.c:3055
 inet6_rtm_newaddr+0x1475/0x1bb0 net/ipv6/addrconf.c:5094
 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:7076
 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2556
page last free pid 14538 tgid 14538 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
 alloc_filename fs/namei.c:147 [inline]
 do_getname+0x35/0x390 fs/namei.c:187
 getname_flags fs/namei.c:230 [inline]
 class_filename_flags_constructor include/linux/fs.h:2566 [inline]
 user_path_at+0x26/0x60 fs/namei.c:3640
 ksys_umount fs/namespace.c:2067 [inline]
 __do_sys_umount fs/namespace.c:2075 [inline]
 __se_sys_umount fs/namespace.c:2073 [inline]
 __ia32_sys_umount+0x109/0x190 fs/namespace.c:2073
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xe7/0x970 arch/x86/entry/syscall_32.c:307
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Memory state around the buggy address:
 ffff88806d6d4300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88806d6d4380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88806d6d4400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88806d6d4480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88806d6d4500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	20 44 88 74          	and    %al,0x74(%rax,%rcx,4)
   4:	24 1e                	and    $0x1e,%al
   6:	45 89 ee             	mov    %r13d,%r14d
   9:	48 c7 c7 c0 7a cd 8b 	mov    $0xffffffff8bcd7ac0,%rdi
  10:	e8 f8 f6 ef 09       	call   0x9eff70d
  15:	31 d2                	xor    %edx,%edx
  17:	65 66 89 15 b6 4b 9b 	mov    %dx,%gs:0x129b4bb6(%rip)        # 0x129b4bd5
  1e:	12
  1f:	e8 69 75 49 00       	call   0x49758d
  24:	fb                   	sti
  25:	bb ff ff ff ff       	mov    $0xffffffff,%ebx
* 2a:	49 c7 c4 c0 a0 80 8e 	mov    $0xffffffff8e80a0c0,%r12 <-- trapping instruction
  31:	41 0f bc de          	bsf    %r14d,%ebx
  35:	83 c3 01             	add    $0x1,%ebx
  38:	0f 85 a4 00 00 00    	jne    0xe2
  3e:	e9                   	.byte 0xe9
  3f:	1b                   	.byte 0x1b