ret_from_fork+0x514/0xb70 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 PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 10 Comm: kworker/0:1 Not tainted syzkaller #0 PREEMPT_{RT,(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+0x517/0x1840 drivers/media/test-drivers/vidtv/vidtv_s302m.c:414
Code: eb 0a e8 4c f3 ef f9 48 8b 5c 24 10 48 8b 44 24 18 42 80 3c 20 00 74 08 48 89 df e8 03 66 59 fa 4c 8b 33 4c 89 f0 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 6c 12 00 00 41 c7 06 5b 04 00 00 48 8b
RSP: 0018:ffffc900000f74a0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8880347ff128 RCX: ffff88801ca83e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900000f7630 R08: 0000000000000dc0 R09: 00000000ffffffff
R10: dffffc0000000000 R11: fffffbfff1c6134f R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880347ff168
FS:  0000000000000000(0000) GS:ffff888125c41000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f993a7a2e9c CR3: 000000003f7ee000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 vidtv_mux_poll_encoders drivers/media/test-drivers/vidtv/vidtv_mux.c:339 [inline]
 vidtv_mux_tick+0x135c/0x24b0 drivers/media/test-drivers/vidtv/vidtv_mux.c:416
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 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+0x517/0x1840 drivers/media/test-drivers/vidtv/vidtv_s302m.c:414
Code: eb 0a e8 4c f3 ef f9 48 8b 5c 24 10 48 8b 44 24 18 42 80 3c 20 00 74 08 48 89 df e8 03 66 59 fa 4c 8b 33 4c 89 f0 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 6c 12 00 00 41 c7 06 5b 04 00 00 48 8b
RSP: 0018:ffffc900000f74a0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8880347ff128 RCX: ffff88801ca83e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900000f7630 R08: 0000000000000dc0 R09: 00000000ffffffff
R10: dffffc0000000000 R11: fffffbfff1c6134f R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880347ff168
FS:  0000000000000000(0000) GS:ffff888125c41000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f993a7a2e9c CR3: 000000003f7ee000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	eb 0a                	jmp    0xc
   2:	e8 4c f3 ef f9       	call   0xf9eff353
   7:	48 8b 5c 24 10       	mov    0x10(%rsp),%rbx
   c:	48 8b 44 24 18       	mov    0x18(%rsp),%rax
  11:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1)
  16:	74 08                	je     0x20
  18:	48 89 df             	mov    %rbx,%rdi
  1b:	e8 03 66 59 fa       	call   0xfa596623
  20:	4c 8b 33             	mov    (%rbx),%r14
  23:	4c 89 f0             	mov    %r14,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 20       	movzbl (%rax,%r12,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 6c 12 00 00    	jne    0x12a3
  37:	41 c7 06 5b 04 00 00 	movl   $0x45b,(%r14)
  3e:	48                   	rex.W
  3f:	8b                   	.byte 0x8b