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

Use-after-free read at 0xffff88823c44c018 (in kfence-#37):
 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-#37: 0xffff88823c44ce00-0xffff88823c44cfff, size=512, cache=kmalloc-cg-512

allocated by task 5048 on cpu 0 at 1549.316616s (5.033870s ago):
 __alloc_skb+0x2c1/0x7d0
 alloc_skb_with_frags+0xc8/0x760
 sock_alloc_send_pskb+0x878/0x990
 unix_dgram_sendmsg+0x460/0x18d0
 __sys_sendto+0x672/0x710
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

freed by task 5041 on cpu 0 at 1549.316726s (5.050509s ago):
 skb_release_data+0x828/0xa60
 __kfree_skb+0x5d/0x210
 __unix_dgram_recvmsg+0x9df/0xd60
 sock_recvmsg+0x172/0x1b0
 sock_read_iter+0x251/0x320
 vfs_read+0x582/0xa70
 ksys_read+0x150/0x270
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 12027 Comm: syz.1.13270 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 47 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 9c 47 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:ffffc9000755f770 EFLAGS: 00010246
RAX: 1ffff11047889803 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000008 RDI: 00000000ffffffff
RBP: ffff8881122d6800 R08: ffffffff8f8cab8f R09: 1ffffffff1f19571
R10: dffffc0000000000 R11: fffffbfff1f19572 R12: ffff88823c44c018
R13: dffffc0000000000 R14: ffff88816cb4a570 R15: ffff88823c44c000
FS:  00007f29de2516c0(0000) GS:ffff88818dc90000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff88823c44c018 CR3: 000000011303e000 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: 0033:0x7f29dd35d60e
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:00007f29de250b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f29de2516c0 RCX: 00007f29dd35d60e
RDX: 0000000000000000 RSI: 00007f29de250c00 RDI: ffffffffffffff9c
RBP: 00007f29de250c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f29dd616038 R14: 00007f29dd615fa0 R15: 00007ffea668a388
 </TASK>
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