ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 10 Comm: kworker/0:1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: events vidtv_mux_tick
RIP: 0010:vidtv_s302m_encode+0x269/0x1860 drivers/media/test-drivers/vidtv/vidtv_s302m.c:414
Code: a8 aa f9 31 ff 89 de e8 f5 a2 aa f9 84 db 0f 85 37 0d 00 00 e8 d8 a8 aa f9 4c 89 e2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e e7 14 00 00 48 8b 44 24 08 41
RSP: 0018:ffffc900000f7830 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000400
RDX: 0000000000000000 RSI: ffffffff885fb948 RDI: ffff88813fe238c0
RBP: 0000000000000000 R08: 0000000000000dc0 R09: 00000000ffffffff
R10: ffffffff8edee6f3 R11: ffffffffffff0408 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff88801c727200 R15: ffff88802d9a1000
FS:  0000000000000000(0000) GS:ffff888123dd8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff6af97e10 CR3: 0000000076f29000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 vidtv_mux_poll_encoders drivers/media/test-drivers/vidtv/vidtv_mux.c:339 [inline]
 vidtv_mux_tick+0x4e4/0x1460 drivers/media/test-drivers/vidtv/vidtv_mux.c:416
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:vidtv_s302m_encode+0x269/0x1860 drivers/media/test-drivers/vidtv/vidtv_s302m.c:414
Code: a8 aa f9 31 ff 89 de e8 f5 a2 aa f9 84 db 0f 85 37 0d 00 00 e8 d8 a8 aa f9 4c 89 e2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e e7 14 00 00 48 8b 44 24 08 41
RSP: 0018:ffffc900000f7830 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000400
RDX: 0000000000000000 RSI: ffffffff885fb948 RDI: ffff88813fe238c0
RBP: 0000000000000000 R08: 0000000000000dc0 R09: 00000000ffffffff
R10: ffffffff8edee6f3 R11: ffffffffffff0408 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff88801c727200 R15: ffff88802d9a1000
FS:  0000000000000000(0000) GS:ffff888123dd8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a60e551be0 CR3: 000000000e994000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	a8 aa                	test   $0xaa,%al
   2:	f9                   	stc
   3:	31 ff                	xor    %edi,%edi
   5:	89 de                	mov    %ebx,%esi
   7:	e8 f5 a2 aa f9       	call   0xf9aaa301
   c:	84 db                	test   %bl,%bl
   e:	0f 85 37 0d 00 00    	jne    0xd4b
  14:	e8 d8 a8 aa f9       	call   0xf9aaa8f1
  19:	4c 89 e2             	mov    %r12,%rdx
  1c:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  23:	fc ff df
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	0f b6 04 02          	movzbl (%rdx,%rax,1),%eax <-- trapping instruction
  2e:	84 c0                	test   %al,%al
  30:	74 08                	je     0x3a
  32:	3c 03                	cmp    $0x3,%al
  34:	0f 8e e7 14 00 00    	jle    0x1521
  3a:	48 8b 44 24 08       	mov    0x8(%rsp),%rax
  3f:	41                   	rex.B