==================================================================
BUG: KFENCE: use-after-free read in dvb_device_open+0xc4/0x340

Use-after-free read at 0xffff88823c43af18 (in kfence-#28):
 dvb_device_open+0xc4/0x340
 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

kfence-#28: 0xffff88823c43af00-0xffff88823c43afd7, size=216, cache=kmalloc-256

allocated by task 1 on cpu 0 at 12.753931s (71.332260s ago):
 dvb_register_device+0x309/0x1dd0
 dvb_register_frontend+0x603/0x900
 vidtv_bridge_probe+0x9d5/0xf60
 platform_probe+0xf9/0x190
 really_probe+0x254/0xae0
 __driver_probe_device+0x1e8/0x360
 driver_probe_device+0x4f/0x240
 __driver_attach+0x339/0x600
 bus_for_each_dev+0x23b/0x2c0
 bus_add_driver+0x345/0x670
 driver_register+0x23a/0x320
 vidtv_bridge_init+0x3d/0x60
 do_one_initcall+0x250/0x870
 do_initcall_level+0x10a/0x1a0
 do_initcalls+0x59/0xa0
 kernel_init_freeable+0x29d/0x3e0
 kernel_init+0x1d/0x1d0
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30

freed by task 6062 on cpu 0 at 76.517964s (7.599957s ago):
 dvb_device_open+0x2b8/0x340
 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

CPU: 1 UID: 0 PID: 6180 Comm: syz.0.129 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
RIP: 0010:dvb_device_open+0xc4/0x340
Code: e8 01 5c 2b fa 4d 8b 3f 4d 85 ff 0f 84 09 01 00 00 4d 8d 67 18 4c 89 e0 48 c1 e8 03 80 3c 18 00 74 08 4c 89 e7 e8 dc 5b 2b fa <4d> 8b 2c 24 4d 85 ed 0f 84 ea 00 00 00 4c 89 e8 48 c1 e8 03 80 3c
RSP: 0018:ffffc90006d77870 EFLAGS: 00010246
RAX: 1ffff110478875e3 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000008 RDI: 00000000ffffffff
RBP: ffff8881bf2ad000 R08: ffffffff8fb1deaf R09: 1ffffffff1f63bd5
R10: dffffc0000000000 R11: fffffbfff1f63bd6 R12: ffff88823c43af18
R13: dffffc0000000000 R14: ffff8881073a3790 R15: ffff88823c43af00
FS:  00007fe4eeb9a6c0(0000) GS:ffff8882a8f5c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff88823c43af18 CR3: 000000011460c000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 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: 0033:0x7fe4edd5e90e
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:00007fe4eeb99b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fe4eeb9a6c0 RCX: 00007fe4edd5e90e
RDX: 0000000000040002 RSI: 00007fe4eeb99c00 RDI: ffffffffffffff9c
RBP: 00007fe4eeb99c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007fe4ee026128 R14: 00007fe4ee026090 R15: 00007ffca91adc08
 </TASK>
==================================================================
