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BUG: KASAN: slab-use-after-free in v4l2_fh_open+0xac/0x420
Read of size 8 at addr ffff88801a9b8740 by task v4l_id/31174

CPU: 1 UID: 0 PID: 31174 Comm: v4l_id Not tainted syzkaller #0 PREEMPT(full) 
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+0x189/0x250
 print_report+0xca/0x240
 kasan_report+0x118/0x150
 v4l2_fh_open+0xac/0x420
 em28xx_v4l2_open+0x157/0x9a0
 v4l2_open+0x1bf/0x3a0
 chrdev_open+0x4cc/0x5e0
 do_dentry_open+0x953/0x13f0
 vfs_open+0x3b/0x340
 path_openat+0x2ee5/0x3830
 do_filp_open+0x1fa/0x410
 do_sys_openat2+0x121/0x1c0
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f01727169a4
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:00007ffdfb8a3660 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ffdfb8a3878 RCX: 00007f01727169a4
RDX: 0000000000000000 RSI: 00007ffdfb8a3f18 RDI: 00000000ffffff9c
RBP: 00007ffdfb8a3f18 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffdfb8a3890 R14: 000055f6d199e670 R15: 00007f0172c81a80
 </TASK>

Allocated by task 15051:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_cache_noprof+0x3d5/0x6f0
 em28xx_v4l2_init+0x10b/0x2e70
 em28xx_init_extension+0x120/0x1c0
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 ret_from_fork_asm+0x1a/0x30

Freed by task 15051:
 kasan_save_track+0x3e/0x80
 __kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5c/0x80
 kfree+0x19a/0x6d0
 em28xx_v4l2_init+0x1683/0x2e70
 em28xx_init_extension+0x120/0x1c0
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 ret_from_fork_asm+0x1a/0x30

The buggy address belongs to the object at ffff88801a9b8000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 1856 bytes inside of
 freed 8192-byte region [ffff88801a9b8000, ffff88801a9ba000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1a9b8
head: order:3 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 ffff888100042280 ffffea0000a55000 dead000000000002
raw: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff888100042280 ffffea0000a55000 dead000000000002
head: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea00006a6e01 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 27376, tgid 27375 (syz.8.5210), ts 811537260154, free_ts 810828065211
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x2365/0x2440
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 allocate_slab+0x96/0x3a0
 ___slab_alloc+0xe94/0x18a0
 __slab_alloc+0x65/0x100
 __kmalloc_noprof+0x471/0x7f0
 snd_seq_oss_readq_new+0x81/0x250
 snd_seq_oss_open+0x770/0xea0
 odev_open+0x67/0xd0
 chrdev_open+0x4cc/0x5e0
 do_dentry_open+0x953/0x13f0
 vfs_open+0x3b/0x340
 path_openat+0x2ee5/0x3830
 do_filp_open+0x1fa/0x410
page last free pid 27356 tgid 27355 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 __folio_put+0x21b/0x2c0
 skb_release_data+0x49a/0x7c0
 napi_consume_skb+0x158/0x1e0
 skb_defer_free_flush+0x18f/0x250
 net_rx_action+0x7b2/0xdf0
 handle_softirqs+0x286/0x870
 do_softirq+0xec/0x180
 __local_bh_enable_ip+0x17d/0x1c0
 netlink_insert+0xd3/0x1370
 netlink_autobind+0x22e/0x300
 netlink_sendmsg+0x523/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260

Memory state around the buggy address:
 ffff88801a9b8600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801a9b8680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801a9b8700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff88801a9b8780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801a9b8800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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