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BUG: KASAN: slab-use-after-free in v4l2_open+0x397/0x3a0
Read of size 4 at addr ffff8881111ec860 by task v4l_id/8293

CPU: 0 UID: 0 PID: 8293 Comm: v4l_id Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 print_address_description+0x55/0x1e0
 print_report+0x58/0x70
 kasan_report+0x117/0x150
 v4l2_open+0x397/0x3a0
 chrdev_open+0x4d9/0x600
 do_dentry_open+0x816/0x1380
 vfs_open+0x3b/0x340
 path_openat+0x2e44/0x3830
 do_file_open+0x23e/0x4a0
 do_sys_openat2+0x115/0x200
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcffa7169a4
Code: 24 20 48 8d 44 24 30 48 89 44 24 28 64 8b 04 25 18 00 00 00 85 c0 75 2c 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 76 60 48 8b 15 55 a4 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffc41ccc820 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ffc41ccca38 RCX: 00007fcffa7169a4
RDX: 0000000000000000 RSI: 00007ffc41ccdf1a RDI: 00000000ffffff9c
RBP: 00007ffc41ccdf1a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc41ccca50 R14: 000055acf5b62670 R15: 00007fcffabaca80
 </TASK>

Allocated by task 5673:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_cache_noprof+0x32d/0x660
 em28xx_v4l2_init+0x103/0x3300
 em28xx_init_extension+0x120/0x1d0
 process_scheduled_works+0xa8e/0x14e0
 worker_thread+0xa47/0xfb0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30

Freed by task 5673:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x40/0x50
 __kasan_slab_free+0x5c/0x80
 kfree+0x1c5/0x640
 em28xx_v4l2_init+0x1919/0x3300
 em28xx_init_extension+0x120/0x1d0
 process_scheduled_works+0xa8e/0x14e0
 worker_thread+0xa47/0xfb0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30

The buggy address belongs to the object at ffff8881111ec000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 2144 bytes inside of
 freed 8192-byte region [ffff8881111ec000, ffff8881111ee000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1111e8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x17ff00000000040(head|node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000040 ffff888100042280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 017ff00000000040 ffff888100042280 dead000000000100 dead000000000122
head: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 017ff00000000003 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 19965, tgid 19965 (syz-executor), ts 573989437278
 post_alloc_hook+0x1f9/0x250
 get_page_from_freelist+0x220d/0x2280
 __alloc_frozen_pages_noprof+0x1a6/0x390
 allocate_slab+0x79/0x5e0
 refill_objects+0x2d5/0x350
 __pcs_replace_empty_main+0x2bf/0x6b0
 __kvmalloc_node_noprof+0x66b/0x860
 pfifo_fast_init+0x372/0x6c0
 qdisc_create_dflt+0x13b/0x4e0
 dev_activate+0x37a/0x1150
 __dev_open+0x699/0x850
 __dev_change_flags+0x329/0x820
 netif_change_flags+0x7c/0x1b0
 do_setlink+0xdd6/0x4670
 rtnl_newlink+0x15c2/0x1bd0
 rtnetlink_rcv_msg+0x802/0xc00
page last free pid 19965 tgid 19965 ts 573917712563 stack trace:
 __free_frozen_pages+0xc1e/0xd10
 __slab_free+0x274/0x2c0
 qlist_free_all+0x99/0x100
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 __kmalloc_cache_noprof+0x2ab/0x660
 __kthread_create_on_node+0x115/0x3d0
 kthread_create_on_node+0xeb/0x140
 netif_napi_add_weight_locked+0x699/0x940
 wg_peer_create+0x52d/0x860
 wg_set_device_doit+0xf3a/0x2120
 genl_family_rcv_msg_doit+0x233/0x340
 genl_rcv_msg+0x614/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x7bb/0x940

Memory state around the buggy address:
 ffff8881111ec700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881111ec780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881111ec800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff8881111ec880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881111ec900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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