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BUG: KASAN: slab-use-after-free in v4l2_fh_open+0xc7/0x430
Read of size 8 at addr ffff888121c30738 by task v4l_id/10199

CPU: 0 UID: 0 PID: 10199 Comm: v4l_id Not tainted 6.16.0-rc7-syzkaller-dirty #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/0x230
 kasan_report+0x118/0x150
 v4l2_fh_open+0xc7/0x430
 em28xx_v4l2_open+0x157/0x9a0
 v4l2_open+0x20f/0x360
 chrdev_open+0x4cc/0x5e0
 do_dentry_open+0xdf3/0x1970
 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/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5fc778c9a4
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:00007ffe4f2873d0 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ffe4f2875e8 RCX: 00007f5fc778c9a4
RDX: 0000000000000000 RSI: 00007ffe4f288f1c RDI: 00000000ffffff9c
RBP: 00007ffe4f288f1c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe4f287600 R14: 0000558428818670 R15: 00007f5fc794fa80
 </TASK>

Allocated by task 790:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_cache_noprof+0x230/0x3d0
 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+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30

Freed by task 790:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x62/0x70
 kfree+0x18e/0x440
 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+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30

The buggy address belongs to the object at ffff888121c30000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 1848 bytes inside of
 freed 8192-byte region [ffff888121c30000, ffff888121c32000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x121c30
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000040 ffff88801a442280 ffffea000440d600 0000000000000002
raw: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000
head: 057ff00000000040 ffff88801a442280 ffffea000440d600 0000000000000002
head: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000
head: 057ff00000000003 ffffea0004870c01 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 9894, tgid 9892 (syz.4.486), ts 171321237384, free_ts 171232054073
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x21e4/0x22c0
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 allocate_slab+0x8a/0x3b0
 ___slab_alloc+0xbfc/0x1480
 __kmalloc_noprof+0x305/0x4f0
 mb_cache_create+0x15f/0x540
 ext4_fill_super+0x4465/0x6080
 get_tree_bdev_flags+0x40e/0x4d0
 vfs_get_tree+0x92/0x2b0
 do_new_mount+0x24a/0xa40
 __se_sys_mount+0x317/0x410
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 24 tgid 24 stack trace:
 __free_frozen_pages+0xc71/0xe70
 __put_partials+0x161/0x1c0
 put_cpu_partial+0x17c/0x250
 __slab_free+0x2f7/0x400
 qlist_free_all+0x97/0x140
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0
 __alloc_skb+0x112/0x2d0
 mld_newpack+0x13c/0xc40
 add_grhead+0x5a/0x2a0
 add_grec+0x13b2/0x1670
 mld_send_initial_cr+0x22d/0x4c0
 mld_dad_work+0x45/0x520
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0

Memory state around the buggy address:
 ffff888121c30600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888121c30680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888121c30700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff888121c30780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888121c30800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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