[syzbot] [media?] general protection fault in mxl111sf_ep4_streaming_ctrl

[syzbot <syzbot+3df044e20e6ff1fb3cf5@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    551c722f4080 Merge tag 'rtc-7.3-fixes' of git://git.kernel..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=10a37b25580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9d4242cb1c54cdf7
dashboard link: https://syzkaller.appspot.com/bug?extid=3df044e20e6ff1fb3cf5
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14f983f5580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3df044e20e6ff1fb3cf5@syzkaller.appspotmail.com

usb 3-1: dvb_usb_v2: could not submit urb no. 0 - get them all back
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000061: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000308-0x000000000000030f]
CPU: 1 UID: 0 PID: 5922 Comm: syz-executor559 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:mxl111sf_ep4_streaming_ctrl+0x2c/0x1a0 drivers/media/usb/dvb-usb-v2/mxl111sf.c:399
Code: 1e fa 55 41 57 41 56 53 89 f3 49 89 fe 49 bf 00 00 00 00 00 fc ff df e8 02 5e 93 f9 49 81 c6 08 03 00 00 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 25 61 03 fa 4d 8b 36 49 83 c6 38
RSP: 0018:ffffc90002fc7b38 EFLAGS: 00010202
RAX: 0000000000000061 RBX: 0000000000000001 RCX: ffff88807ceb8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90002fc7c38 R08: ffffc90002fc7647 R09: 1ffff920005f8ec8
R10: dffffc0000000000 R11: ffffffff88348d10 R12: dffffc0000000000
R13: ffff88805a6753b8 R14: 0000000000000308 R15: dffffc0000000000
FS:  00007f91525696c0(0000) GS:ffff888124dc8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f09f0cd1140 CR3: 000000002f2ca000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 dvb_usb_start_feed+0x57a/0xc70 drivers/media/usb/dvb-usb-v2/dvb_usb_core.c:308
 dmx_ts_feed_start_filtering+0x129/0x220 drivers/media/dvb-core/dvb_demux.c:747
 dvb_dmxdev_start_feed drivers/media/dvb-core/dmxdev.c:658 [inline]
 dvb_dmxdev_filter_start+0x434/0x10d0 drivers/media/dvb-core/dmxdev.c:769
 dvb_demux_do_ioctl+0x48b/0x540 drivers/media/dvb-core/dmxdev.c:1099
 dvb_usercopy+0x199/0x2e0 drivers/media/dvb-core/dvbdev.c:996
 dvb_demux_ioctl+0x29/0x40 drivers/media/dvb-core/dmxdev.c:1208
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9153da4a8b
Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
RSP: 002b:00007f9152569060 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f9153da4a8b
RDX: 00007f91525690d0 RSI: 0000000040146f2c RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f91525690f0
R13: 00007f9153e11fe6 R14: 0000001400000001 R15: 00007ffdf0c12528
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:mxl111sf_ep4_streaming_ctrl+0x2c/0x1a0 drivers/media/usb/dvb-usb-v2/mxl111sf.c:399
Code: 1e fa 55 41 57 41 56 53 89 f3 49 89 fe 49 bf 00 00 00 00 00 fc ff df e8 02 5e 93 f9 49 81 c6 08 03 00 00 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 25 61 03 fa 4d 8b 36 49 83 c6 38
RSP: 0018:ffffc90002fc7b38 EFLAGS: 00010202
RAX: 0000000000000061 RBX: 0000000000000001 RCX: ffff88807ceb8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90002fc7c38 R08: ffffc90002fc7647 R09: 1ffff920005f8ec8
R10: dffffc0000000000 R11: ffffffff88348d10 R12: dffffc0000000000
R13: ffff88805a6753b8 R14: 0000000000000308 R15: dffffc0000000000
FS:  00007f91525696c0(0000) GS:ffff888124cc8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564103601950 CR3: 000000002f2ca000 CR4: 00000000003526f0
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	fa                   	cli
   1:	55                   	push   %rbp
   2:	41 57                	push   %r15
   4:	41 56                	push   %r14
   6:	53                   	push   %rbx
   7:	89 f3                	mov    %esi,%ebx
   9:	49 89 fe             	mov    %rdi,%r14
   c:	49 bf 00 00 00 00 00 	movabs $0xdffffc0000000000,%r15
  13:	fc ff df
  16:	e8 02 5e 93 f9       	call   0xf9935e1d
  1b:	49 81 c6 08 03 00 00 	add    $0x308,%r14
  22:	4c 89 f0             	mov    %r14,%rax
  25:	48 c1 e8 03          	shr    $0x3,%rax
* 29:	42 80 3c 38 00       	cmpb   $0x0,(%rax,%r15,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	4c 89 f7             	mov    %r14,%rdi
  33:	e8 25 61 03 fa       	call   0xfa03615d
  38:	4d 8b 36             	mov    (%r14),%r14
  3b:	49 83 c6 38          	add    $0x38,%r14


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