==================================================================
BUG: KASAN: slab-use-after-free in __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:155 [inline]
BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:181
Read of size 1 at addr ffff88802aec7018 by task ksoftirqd/0/15

CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
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:585
 kasan_check_byte include/linux/kasan.h:402 [inline]
 lock_acquire kernel/locking/lockdep.c:5916 [inline]
 lock_acquire+0x132/0x380 kernel/locking/lockdep.c:5899
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:155 [inline]
 _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:181
 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:3335
 __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+0xb9/0xe0 arch/x86/kernel/irq.c:273
 </IRQ>
 <TASK>
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:665
RIP: 0010:kasan_byte_accessible+0x15/0x30 mm/kasan/generic.c:210
Code: 00 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 48 b8 00 00 00 00 00 fc ff df 48 c1 ef 03 48 01 c7 <0f> b6 07 3c 07 0f 96 c0 e9 4e c3 56 09 66 66 2e 0f 1f 84 00 00 00
RSP: 0018:ffffc9000041f750 EFLAGS: 00000286
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff81b96261 RDI: fffffbfff1fbd874
RBP: ffffffff8fdec3a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000200 R11: 0000000000017ee8 R12: ffffffff81b96261
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 __kasan_check_byte+0x13/0x50 mm/kasan/common.c:584
 kasan_check_byte include/linux/kasan.h:402 [inline]
 lock_acquire kernel/locking/lockdep.c:5916 [inline]
 lock_acquire+0x132/0x380 kernel/locking/lockdep.c:5899
 rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
 unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 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:264 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:296
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2748 [inline]
 slab_free_after_rcu_debug+0xdf/0x170 mm/slub.c:6571
 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
 run_ksoftirqd kernel/softirq.c:1099 [inline]
 run_ksoftirqd+0x38/0x60 kernel/softirq.c:1091
 smpboot_thread_fn+0x3d3/0xab0 kernel/smpboot.c:160
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 9249:
 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:409 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:426
 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]
 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:1932
 fc_mount fs/namespace.c:1278 [inline]
 do_new_mount_fc fs/namespace.c:3885 [inline]
 do_new_mount fs/namespace.c:3961 [inline]
 path_mount+0x7d0/0x2850 fs/namespace.c:4312
 do_mount fs/namespace.c:4325 [inline]
 __do_sys_mount fs/namespace.c:4543 [inline]
 __se_sys_mount fs/namespace.c:4520 [inline]
 __ia32_sys_mount+0x292/0x310 fs/namespace.c:4520
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
 __do_fast_syscall_32+0x13a/0x8b0 arch/x86/entry/syscall_32.c:291
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Freed by task 9249:
 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:264 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:296
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2748 [inline]
 slab_free mm/slub.c:6509 [inline]
 kfree+0x22b/0x6d0 mm/slub.c:6802
 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:1932
 fc_mount fs/namespace.c:1278 [inline]
 do_new_mount_fc fs/namespace.c:3885 [inline]
 do_new_mount fs/namespace.c:3961 [inline]
 path_mount+0x7d0/0x2850 fs/namespace.c:4312
 do_mount fs/namespace.c:4325 [inline]
 __do_sys_mount fs/namespace.c:4543 [inline]
 __se_sys_mount fs/namespace.c:4520 [inline]
 __ia32_sys_mount+0x292/0x310 fs/namespace.c:4520
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
 __do_fast_syscall_32+0x13a/0x8b0 arch/x86/entry/syscall_32.c:291
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

The buggy address belongs to the object at ffff88802aec7000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 24 bytes inside of
 freed 512-byte region [ffff88802aec7000, ffff88802aec7200)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2aec4
head: order:2 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 ffff88801d042c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801d042c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000002 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 1160, tgid 1160 (kworker/u33:11), ts 39643542377
 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:7418
 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]
 __do_kmalloc_node mm/slub.c:5413 [inline]
 __kmalloc_noprof+0x67c/0x840 mm/slub.c:5439
 _kmalloc_noprof include/linux/slab.h:995 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 fib6_info_alloc+0x40/0x160 net/ipv6/ip6_fib.c:155
 ip6_route_info_create+0x14c/0xad0 net/ipv6/route.c:3839
 ip6_route_add+0x4b/0x1d0 net/ipv6/route.c:3968
 addrconf_add_mroute+0x1de/0x350 net/ipv6/addrconf.c:2568
 addrconf_add_dev+0x14e/0x1a0 net/ipv6/addrconf.c:2586
 addrconf_dev_config net/ipv6/addrconf.c:3508 [inline]
 addrconf_init_auto_addrs+0x10e/0x780 net/ipv6/addrconf.c:3596
 addrconf_notify+0xa10/0x1ba0 net/ipv6/addrconf.c:3776
 notifier_call_chain+0x99/0x3f0 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2275
page last free pid 112 tgid 112 ts 39425849708 stack trace:
 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
 shrink_folio_list+0x455c/0x5e40 mm/vmscan.c:1511
 evict_folios+0x348/0x1650 mm/vmscan.c:4910
 try_to_shrink_lruvec+0x366/0x830 mm/vmscan.c:5076
 shrink_one+0x307/0x850 mm/vmscan.c:5117
 shrink_many mm/vmscan.c:5180 [inline]
 lru_gen_shrink_node mm/vmscan.c:5258 [inline]
 shrink_node+0x2b20/0x4320 mm/vmscan.c:6247
 kswapd_shrink_node mm/vmscan.c:7101 [inline]
 balance_pgdat+0xb20/0x1f00 mm/vmscan.c:7279
 kswapd+0x556/0xb50 mm/vmscan.c:7555
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff88802aec6f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802aec6f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802aec7000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88802aec7080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802aec7100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	0f 1f 00             	nopl   (%rax)
   5:	90                   	nop
   6:	90                   	nop
   7:	90                   	nop
   8:	90                   	nop
   9:	90                   	nop
   a:	90                   	nop
   b:	90                   	nop
   c:	90                   	nop
   d:	90                   	nop
   e:	90                   	nop
   f:	90                   	nop
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	0f 1f 40 d6          	nopl   -0x2a(%rax)
  19:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  20:	fc ff df
  23:	48 c1 ef 03          	shr    $0x3,%rdi
  27:	48 01 c7             	add    %rax,%rdi
* 2a:	0f b6 07             	movzbl (%rdi),%eax <-- trapping instruction
  2d:	3c 07                	cmp    $0x7,%al
  2f:	0f 96 c0             	setbe  %al
  32:	e9 4e c3 56 09       	jmp    0x956c385
  37:	66                   	data16
  38:	66                   	data16
  39:	2e                   	cs
  3a:	0f                   	.byte 0xf
  3b:	1f                   	(bad)
  3c:	84 00                	test   %al,(%rax)