==================================================================
BUG: KFENCE: use-after-free read in dvb_device_open+0xc4/0x350

Use-after-free read at 0xffff88823c43c018 (in kfence-#29):
 dvb_device_open+0xc4/0x350
 chrdev_open+0x4cd/0x5e0
 do_dentry_open+0x785/0x14e0
 vfs_open+0x3b/0x340
 path_openat+0x2e08/0x3860
 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

kfence-#29: 0xffff88823c43c000-0xffff88823c43c0d7, size=216, cache=kmalloc-256

allocated by task 1 on cpu 1 at 18.280351s (60.281379s ago):
 dvb_register_device+0x2fd/0x21e0
 dvb_register_frontend+0x61b/0x920
 vidtv_bridge_probe+0x9aa/0xf80
 platform_probe+0xf9/0x190
 really_probe+0x267/0xaf0
 __driver_probe_device+0x1ef/0x380
 driver_probe_device+0x4f/0x240
 __driver_attach+0x34c/0x640
 bus_for_each_dev+0x23b/0x2c0
 bus_add_driver+0x345/0x670
 driver_register+0x23a/0x320
 vidtv_bridge_init+0x28/0x50
 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
 ret_from_fork_asm+0x1a/0x30

freed by task 6179 on cpu 1 at 76.358562s (2.236879s ago):
 dvb_device_open+0x2cd/0x350
 chrdev_open+0x4cd/0x5e0
 do_dentry_open+0x785/0x14e0
 vfs_open+0x3b/0x340
 path_openat+0x2e08/0x3860
 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

CPU: 1 UID: 0 PID: 6218 Comm: syz.2.102 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+0xc4/0x350
Code: e8 f1 56 4b fa 4d 8b 3f 4d 85 ff 0f 84 64 01 00 00 4d 8d 67 18 4c 89 e0 48 c1 e8 03 80 3c 18 00 74 08 4c 89 e7 e8 cc 56 4b fa <4d> 8b 2c 24 4d 85 ed 0f 84 45 01 00 00 4c 89 e8 48 c1 e8 03 80 3c
RSP: 0018:ffffc9000373f770 EFLAGS: 00010246
RAX: 1ffff11047887803 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000008 RDI: 00000000ffffffff
RBP: ffff8881783db400 R08: ffffffff8f8cad0f R09: 1ffffffff1f195a1
R10: dffffc0000000000 R11: fffffbfff1f195a2 R12: ffff88823c43c018
R13: dffffc0000000000 R14: ffff8881053ac398 R15: ffff88823c43c000
FS:  00007ff55853e6c0(0000) GS:ffff8882a9291000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff88823c43c018 CR3: 0000000177a64000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 chrdev_open+0x4cd/0x5e0
 do_dentry_open+0x785/0x14e0
 vfs_open+0x3b/0x340
 path_openat+0x2e08/0x3860
 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: 0033:0x7ff55755d60e
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:00007ff55853db28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ff55853e6c0 RCX: 00007ff55755d60e
RDX: 0000000000000002 RSI: 00007ff55853dc00 RDI: ffffffffffffff9c
RBP: 00007ff55853dc00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007ff557816038 R14: 00007ff557815fa0 R15: 00007ffcb84fb418
 </TASK>
==================================================================
