BUG: KASAN: slab-use-after-free in dvb_device_open+0xc4/0x360
Read of size 8 at addr ffff88816ebeec18 by task syz.4.8561/31569

CPU: 1 UID: 0 PID: 31569 Comm: syz.4.8561 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(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
 dvb_device_open+0xc4/0x360
 chrdev_open+0x4d0/0x5f0
 do_dentry_open+0x83d/0x13e0
 vfs_open+0x3b/0x350
 path_openat+0x2e43/0x38a0
 do_file_open+0x23e/0x4a0
 do_sys_openat2+0x113/0x200
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fae3512d60e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007fae333bdb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fae333be6c0 RCX: 00007fae3512d60e
RDX: 0000000000000002 RSI: 00007fae333bdc00 RDI: ffffffffffffff9c
RBP: 00007fae333bdc00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007fae353e6038 R14: 00007fae353e5fa0 R15: 00007ffea9295e08
 </TASK>

Allocated by task 31285:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_cache_noprof+0x3a6/0x690
 kernfs_fop_open+0x39a/0xcb0
 do_dentry_open+0x83d/0x13e0
 vfs_open+0x3b/0x350
 path_openat+0x2e43/0x38a0
 do_file_open+0x23e/0x4a0
 do_sys_openat2+0x113/0x200
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 31285:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5c/0x80
 kfree+0x1c5/0x6c0
 kernfs_fop_release+0x335/0x450
 __fput+0x461/0xa70
 fput_close_sync+0x11f/0x240
 __x64_sys_close+0x7e/0x110
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88816ebeec00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 24 bytes inside of
 freed 512-byte region [ffff88816ebeec00, ffff88816ebeee00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16ebec
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x500000000000040(head|node=1|zone=2)
page_type: f5(slab)
raw: 0500000000000040 ffff888100041c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0500000000000040 ffff888100041c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0500000000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff
head: 0000000000000000 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 1, tgid 1 (swapper/0), ts 16011280587, free_ts 0
 post_alloc_hook+0x1f9/0x250
 get_page_from_freelist+0x27d6/0x2850
 __alloc_frozen_pages_noprof+0x18d/0x380
 allocate_slab+0x74/0x5e0
 refill_objects+0x33c/0x3d0
 __pcs_replace_empty_main+0x373/0x720
 __kmalloc_cache_noprof+0x44e/0x690
 bus_add_driver+0x165/0x670
 driver_register+0x23a/0x320
 usb_register_driver+0x1e4/0x390
 do_one_initcall+0x250/0x870
 do_initcall_level+0x104/0x190
 do_initcalls+0x59/0xa0
 kernel_init_freeable+0x2a6/0x3e0
 kernel_init+0x1d/0x1d0
 ret_from_fork+0x514/0xb70
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88816ebeeb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88816ebeeb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88816ebeec00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88816ebeec80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88816ebeed00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
