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

[syzbot]

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=b444c4be6da4c7d1dd99
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
CC: [dwlsa...@gmail.com linux-...@vger.kernel.org linux...@vger.kernel.org mch...@kernel.org]

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+b444c4...@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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