==================================================================
BUG: KASAN: slab-use-after-free in __lock_acquire+0x2de0/0x3cb0 kernel/locking/lockdep.c:5007
Read of size 8 at addr ffff88802bae8c18 by task syz.2.161/5998

CPU: 3 UID: 0 PID: 5998 Comm: syz.2.161 Not tainted 6.11.0-rc6-syzkaller-00048-gc7fb1692dc01 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 __lock_acquire+0x2de0/0x3cb0 kernel/locking/lockdep.c:5007
 lock_acquire kernel/locking/lockdep.c:5759 [inline]
 lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5724
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
 p9_tag_remove net/9p/client.c:397 [inline]
 p9_req_put net/9p/client.c:405 [inline]
 p9_req_put+0xaf/0x250 net/9p/client.c:402
 req_done+0x1e7/0x2f0 net/9p/trans_virtio.c:147
 vring_interrupt drivers/virtio/virtio_ring.c:2595 [inline]
 vring_interrupt+0x31b/0x400 drivers/virtio/virtio_ring.c:2570
 __handle_irq_event_percpu+0x229/0x7c0 kernel/irq/handle.c:158
 handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
 handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210
 handle_edge_irq+0x263/0xd10 kernel/irq/chip.c:831
 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
 handle_irq arch/x86/kernel/irq.c:247 [inline]
 call_irq_handler arch/x86/kernel/irq.c:259 [inline]
 __common_interrupt+0xdf/0x250 arch/x86/kernel/irq.c:285
 common_interrupt+0x52/0xd0 arch/x86/kernel/irq.c:278
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
RIP: 0010:handle_softirqs+0x1da/0x8f0 kernel/softirq.c:540
Code: 89 44 24 18 48 89 6c 24 10 48 c7 c7 e0 76 4b 8b e8 2b dd c6 09 65 66 c7 05 39 d5 b3 7e 00 00 e8 3c 06 43 00 fb bb ff ff ff ff <49> c7 c6 c0 a0 a0 8d 41 0f bc dc 83 c3 01 0f 85 a7 00 00 00 e9 b4
RSP: 0018:ffffc90000908f30 EFLAGS: 00000216
RAX: 0000000000000460 RBX: 00000000ffffffff RCX: 1ffffffff2027fe1
RDX: 0000000000000000 RSI: ffffffff8b4cd740 RDI: ffffffff8bb0f980
RBP: ffff888027bca440 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff9014435f R11: 0000000000000000 R12: 0000000000000002
R13: 000000000000000a R14: 0000000000000001 R15: 0000000000000000
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:finish_task_switch.isra.0+0x220/0xcc0 kernel/sched/core.c:5062
Code: a9 0a 00 00 44 8b 0d 87 23 b8 0e 45 85 c9 0f 85 c0 01 00 00 48 89 df e8 ae f8 ff ff e8 49 b9 36 00 fb 65 48 8b 1d 10 88 a7 7e <48> 8d bb f8 15 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1
RSP: 0018:ffffc900036d7718 EFLAGS: 00000202
RAX: 000000000000045b RBX: ffff888027bca440 RCX: 1ffffffff2027fe1
RDX: 0000000000000000 RSI: ffffffff8b4cd740 RDI: ffffffff8bb0f980
RBP: ffffc900036d7760 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff9014435f R11: 0000000000000000 R12: ffff88806a93fb58
R13: ffff88802837a440 R14: ffff88802406d580 R15: ffff88806a83edc0
 context_switch kernel/sched/core.c:5191 [inline]
 __schedule+0xe3f/0x5490 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6621
 schedule_timeout+0x258/0x2a0 kernel/time/timer.c:2557
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common+0x3de/0x5f0 kernel/sched/completion.c:116
 rdmsr_safe_on_cpu+0x1de/0x210 arch/x86/lib/msr-smp.c:181
 msr_read+0x1a4/0x250 arch/x86/kernel/msr.c:66
 vfs_read+0x1d4/0xbd0 fs/read_write.c:474
 ksys_read+0x12f/0x260 fs/read_write.c:619
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9dcf17cef9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9dcfefa038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f9dcf335f80 RCX: 00007f9dcf17cef9
RDX: 0000000000018ff8 RSI: 0000000020019680 RDI: 0000000000000005
RBP: 00007f9dcf1ef01e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f9dcf335f80 R15: 00007ffe05c3a8c8
 </TASK>

Allocated by task 5999:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387
 kmalloc_noprof include/linux/slab.h:681 [inline]
 p9_client_create+0xcf/0x1210 net/9p/client.c:983
 v9fs_session_init+0x1f8/0x1a80 fs/9p/v9fs.c:410
 v9fs_mount+0xc6/0xa50 fs/9p/vfs_super.c:122
 legacy_get_tree+0x109/0x220 fs/fs_context.c:662
 vfs_get_tree+0x8f/0x380 fs/super.c:1800
 do_new_mount fs/namespace.c:3472 [inline]
 path_mount+0x14e6/0x1f20 fs/namespace.c:3799
 do_mount fs/namespace.c:3812 [inline]
 __do_sys_mount fs/namespace.c:4020 [inline]
 __se_sys_mount fs/namespace.c:3997 [inline]
 __x64_sys_mount+0x294/0x320 fs/namespace.c:3997
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5999:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579
 poison_slab_object+0xf7/0x160 mm/kasan/common.c:240
 __kasan_slab_free+0x32/0x50 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2256 [inline]
 slab_free mm/slub.c:4477 [inline]
 kfree+0x12a/0x3b0 mm/slub.c:4598
 p9_client_create+0xaaa/0x1210 net/9p/client.c:1054
 v9fs_session_init+0x1f8/0x1a80 fs/9p/v9fs.c:410
 v9fs_mount+0xc6/0xa50 fs/9p/vfs_super.c:122
 legacy_get_tree+0x109/0x220 fs/fs_context.c:662
 vfs_get_tree+0x8f/0x380 fs/super.c:1800
 do_new_mount fs/namespace.c:3472 [inline]
 path_mount+0x14e6/0x1f20 fs/namespace.c:3799
 do_mount fs/namespace.c:3812 [inline]
 __do_sys_mount fs/namespace.c:4020 [inline]
 __se_sys_mount fs/namespace.c:3997 [inline]
 __x64_sys_mount+0x294/0x320 fs/namespace.c:3997
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802bae8c00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 24 bytes inside of
 freed 512-byte region [ffff88802bae8c00, ffff88802bae8e00)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2bae8
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: 0xfdffffff(slab)
raw: 00fff00000000040 ffff88801ac42c80 ffffea0000c5b100 dead000000000002
raw: 0000000000000000 0000000080100010 00000001fdffffff 0000000000000000
head: 00fff00000000040 ffff88801ac42c80 ffffea0000c5b100 dead000000000002
head: 0000000000000000 0000000080100010 00000001fdffffff 0000000000000000
head: 00fff00000000002 ffffea0000aeba01 ffffffffffffffff 0000000000000000
head: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x152820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 45, tgid 45 (kworker/u32:2), ts 95259668288, free_ts 95203768860
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1500
 prep_new_page mm/page_alloc.c:1508 [inline]
 get_page_from_freelist+0x1351/0x2e50 mm/page_alloc.c:3446
 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4702
 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
 alloc_slab_page+0x4e/0xf0 mm/slub.c:2325
 allocate_slab mm/slub.c:2488 [inline]
 new_slab+0x84/0x260 mm/slub.c:2541
 ___slab_alloc+0xdac/0x1870 mm/slub.c:3727
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3817
 __slab_alloc_node mm/slub.c:3870 [inline]
 slab_alloc_node mm/slub.c:4029 [inline]
 __kmalloc_cache_noprof+0x2b4/0x300 mm/slub.c:4188
 kmalloc_noprof include/linux/slab.h:681 [inline]
 batadv_forw_packet_alloc+0x3ac/0x4e0 net/batman-adv/send.c:519
 batadv_iv_ogm_aggregate_new+0x132/0x4a0 net/batman-adv/bat_iv_ogm.c:562
 batadv_iv_ogm_queue_add net/batman-adv/bat_iv_ogm.c:670 [inline]
 batadv_iv_ogm_schedule_buff+0xe6d/0x14d0 net/batman-adv/bat_iv_ogm.c:849
 batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:868 [inline]
 batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:861 [inline]
 batadv_iv_send_outstanding_bat_ogm_packet+0x31e/0x8d0 net/batman-adv/bat_iv_ogm.c:1712
 process_one_work+0x9c5/0x1b40 kernel/workqueue.c:3231
 process_scheduled_works kernel/workqueue.c:3312 [inline]
 worker_thread+0x6c8/0xed0 kernel/workqueue.c:3389
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
page last free pid 5428 tgid 5427 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1101 [inline]
 free_unref_page+0x64a/0xe40 mm/page_alloc.c:2619
 stack_depot_save_flags+0x2da/0x8f0 lib/stackdepot.c:666
 kasan_save_stack+0x42/0x60 mm/kasan/common.c:48
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579
 poison_slab_object+0xf7/0x160 mm/kasan/common.c:240
 __kasan_slab_free+0x32/0x50 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2256 [inline]
 slab_free mm/slub.c:4477 [inline]
 kfree+0x12a/0x3b0 mm/slub.c:4598
 memcg_list_lru_alloc+0x472/0xa90 mm/list_lru.c:551
 __memcg_slab_post_alloc_hook+0x12c/0x9c0 mm/memcontrol.c:3005
 memcg_slab_post_alloc_hook mm/slub.c:2164 [inline]
 slab_post_alloc_hook mm/slub.c:4002 [inline]
 slab_alloc_node mm/slub.c:4041 [inline]
 kmem_cache_alloc_lru_noprof+0x2c1/0x2f0 mm/slub.c:4060
 __d_alloc+0x31/0xaa0 fs/dcache.c:1636
 d_alloc+0x4a/0x1e0 fs/dcache.c:1716
 d_alloc_parallel+0xe9/0x12b0 fs/dcache.c:2476
 __lookup_slow+0x194/0x460 fs/namei.c:1703
 lookup_one_len+0x181/0x1b0 fs/namei.c:2837

Memory state around the buggy address:
 ffff88802bae8b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802bae8b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802bae8c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88802bae8c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802bae8d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	89 44 24 18          	mov    %eax,0x18(%rsp)
   4:	48 89 6c 24 10       	mov    %rbp,0x10(%rsp)
   9:	48 c7 c7 e0 76 4b 8b 	mov    $0xffffffff8b4b76e0,%rdi
  10:	e8 2b dd c6 09       	call   0x9c6dd40
  15:	65 66 c7 05 39 d5 b3 	movw   $0x0,%gs:0x7eb3d539(%rip)        # 0x7eb3d558
  1c:	7e 00 00
  1f:	e8 3c 06 43 00       	call   0x430660
  24:	fb                   	sti
  25:	bb ff ff ff ff       	mov    $0xffffffff,%ebx
* 2a:	49 c7 c6 c0 a0 a0 8d 	mov    $0xffffffff8da0a0c0,%r14 <-- trapping instruction
  31:	41 0f bc dc          	bsf    %r12d,%ebx
  35:	83 c3 01             	add    $0x1,%ebx
  38:	0f 85 a7 00 00 00    	jne    0xe5
  3e:	e9                   	.byte 0xe9
  3f:	b4                   	.byte 0xb4