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

Use-after-free read at 0xffff88823c412018 (in kfence-#8):
 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+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

kfence-#8: 0xffff88823c412f00-0xffff88823c412fef, size=240, cache=skbuff_head_cache

allocated by task 5804 on cpu 0 at 3539.640989s (6.844421s ago):
 __alloc_skb+0x1d0/0x7d0
 nsim_dev_trap_report_work+0x29a/0xb80
 process_scheduled_works+0xb6e/0x18c0
 worker_thread+0xa53/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30

freed by task 5804 on cpu 0 at 3539.641026s (6.858367s ago):
 nsim_dev_trap_report_work+0x7cf/0xb80
 process_scheduled_works+0xb6e/0x18c0
 worker_thread+0xa53/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30

CPU: 1 UID: 0 PID: 15623 Comm: syz.6.22500 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
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 c1 ee 4f 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 9c ee 4f 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:ffffc90007c8f770 EFLAGS: 00010246
RAX: 1ffff11047882403 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000008 RDI: 00000000ffffffff
RBP: ffff88801ffb9600 R08: ffffffff8f6bc6cf R09: 1ffffffff1ed78d9
R10: dffffc0000000000 R11: fffffbfff1ed78da R12: ffff88823c412018
R13: dffffc0000000000 R14: ffff88816e32f5f0 R15: ffff88823c412000
FS:  00007faa4f3076c0(0000) GS:ffff8882a9460000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff88823c412018 CR3: 00000001b829a000 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+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faa4e35cfce
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:00007faa4f306b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007faa4f3076c0 RCX: 00007faa4e35cfce
RDX: 0000000000000002 RSI: 00007faa4f306c00 RDI: ffffffffffffff9c
RBP: 00007faa4f306c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007faa4e616038 R14: 00007faa4e615fa0 R15: 00007ffc10da1a78
 </TASK>
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