[syzbot] [media?] general protection fault in vidtv_psi_ts_psi_write_into

[syzbot <syzbot+814c351d094f4f1a1b86@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    7f98ab9da046 Merge tag 'for-6.19-rc4-tag' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10082a8a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8bfa57a8c0ab3aa8
dashboard link: https://syzkaller.appspot.com/bug?extid=814c351d094f4f1a1b86
compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/940981af530c/disk-7f98ab9d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7221a482bfe3/vmlinux-7f98ab9d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6861da47f819/bzImage-7f98ab9d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+814c351d094f4f1a1b86@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 5922 Comm: kworker/1:6 Tainted: G          I  L      syzkaller #0 PREEMPT(full) 
Tainted: [I]=FIRMWARE_WORKAROUND, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events vidtv_mux_tick
RIP: 0010:vidtv_psi_ts_psi_write_into+0x4d7/0xbf0 drivers/media/test-drivers/vidtv/vidtv_psi.c:197
Code: 00 4c 8d 7b 20 4c 8b 0b 4c 89 f8 48 c1 e8 03 80 3c 28 00 0f 85 22 05 00 00 48 8b 43 20 48 89 c1 48 89 c6 48 c1 e9 03 83 e6 07 <0f> b6 0c 29 40 38 f1 7f 08 84 c9 0f 85 97 05 00 00 0f b6 08 0f b6
RSP: 0018:ffffc900044af2f0 EFLAGS: 00010202
RAX: 0000000000000002 RBX: ffffc900044af400 RCX: 0000000000000000
RDX: 0000000000016034 RSI: 0000000000000002 RDI: 0000000000000005
RBP: dffffc0000000000 R08: 0000000000000005 R09: ffffc9000bb99000
R10: 0000000000000000 R11: ffffc900044af42c R12: 0000000000000008
R13: 0000000000000000 R14: 0000000000000178 R15: ffffc900044af420
FS:  0000000000000000(0000) GS:ffff8881249fc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000047b24000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 vidtv_psi_table_header_write_into+0x1af/0x240 drivers/media/test-drivers/vidtv/vidtv_psi.c:799
 vidtv_psi_pmt_write_into+0x3a9/0x9e0 drivers/media/test-drivers/vidtv/vidtv_psi.c:1231
 vidtv_mux_push_si+0xc04/0xec0 drivers/media/test-drivers/vidtv/vidtv_mux.c:196
 vidtv_mux_tick+0xe8d/0x14e0 drivers/media/test-drivers/vidtv/vidtv_mux.c:408
 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:vidtv_psi_ts_psi_write_into+0x4d7/0xbf0 drivers/media/test-drivers/vidtv/vidtv_psi.c:197
Code: 00 4c 8d 7b 20 4c 8b 0b 4c 89 f8 48 c1 e8 03 80 3c 28 00 0f 85 22 05 00 00 48 8b 43 20 48 89 c1 48 89 c6 48 c1 e9 03 83 e6 07 <0f> b6 0c 29 40 38 f1 7f 08 84 c9 0f 85 97 05 00 00 0f b6 08 0f b6
RSP: 0018:ffffc900044af2f0 EFLAGS: 00010202
RAX: 0000000000000002 RBX: ffffc900044af400 RCX: 0000000000000000
RDX: 0000000000016034 RSI: 0000000000000002 RDI: 0000000000000005
RBP: dffffc0000000000 R08: 0000000000000005 R09: ffffc9000bb99000
R10: 0000000000000000 R11: ffffc900044af42c R12: 0000000000000008
R13: 0000000000000000 R14: 0000000000000178 R15: ffffc900044af420
FS:  0000000000000000(0000) GS:ffff8881249fc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31d08ff8 CR3: 000000002fa6a000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	00 4c 8d 7b          	add    %cl,0x7b(%rbp,%rcx,4)
   4:	20 4c 8b 0b          	and    %cl,0xb(%rbx,%rcx,4)
   8:	4c 89 f8             	mov    %r15,%rax
   b:	48 c1 e8 03          	shr    $0x3,%rax
   f:	80 3c 28 00          	cmpb   $0x0,(%rax,%rbp,1)
  13:	0f 85 22 05 00 00    	jne    0x53b
  19:	48 8b 43 20          	mov    0x20(%rbx),%rax
  1d:	48 89 c1             	mov    %rax,%rcx
  20:	48 89 c6             	mov    %rax,%rsi
  23:	48 c1 e9 03          	shr    $0x3,%rcx
  27:	83 e6 07             	and    $0x7,%esi
* 2a:	0f b6 0c 29          	movzbl (%rcx,%rbp,1),%ecx <-- trapping instruction
  2e:	40 38 f1             	cmp    %sil,%cl
  31:	7f 08                	jg     0x3b
  33:	84 c9                	test   %cl,%cl
  35:	0f 85 97 05 00 00    	jne    0x5d2
  3b:	0f b6 08             	movzbl (%rax),%ecx
  3e:	0f                   	.byte 0xf
  3f:	b6                   	.byte 0xb6


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