general protection fault in mxl111sf_ep6_streaming_ctrl

Status: upstream: reported C repro on 2026/09/26 22:23
Subsystems: media usb
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+c35815bad054e6ad396e@syzkaller.appspotmail.com
First crash: 22h16m, last: 15h07m
Cause bisection: failed (error log, bisect log)
  
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ID Workflow Result Correct Bug Created Started Finished Revision
5f617a01 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ❌ VMGuestTrigger: ✅ VMHostTrigger: ❌ ❓ general protection fault in mxl111sf_ep6_streaming_ctrl 2026/09/27 00:36 2026/09/27 00:36 2026/09/27 01:31 a3c7249d
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[PATCH v2] media: dvb-usb-v2: set active_fe before the demux goes live 1 (1) 2026/09/27 06:11
[PATCH] media: dvb-usb-v2: set active_fe before the demux goes live 2 (2) 2026/09/27 06:10
[syzbot] [media?] [usb?] general protection fault in mxl111sf_ep6_streaming_ctrl 0 (1) 2026/09/26 22:23

Sample crash report:
usb 1-1: 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 NOPTI
KASAN: null-ptr-deref in range [0x0000000000000308-0x000000000000030f]
CPU: 0 UID: 0 PID: 5651 Comm: syz-executor908 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
RIP: 0010:mxl111sf_ep6_streaming_ctrl+0x2e/0x2e0 drivers/media/usb/dvb-usb-v2/mxl111sf.c:348
Code: 55 41 57 41 56 41 54 53 89 f5 49 89 fe 49 bc 00 00 00 00 00 fc ff df e8 10 62 93 f9 49 8d 9e 08 03 00 00 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 53 66 03 fa 48 8b 1b 48 83 c3 38
RSP: 0018:ffffc900036b7b30 EFLAGS: 00010212
RAX: 0000000000000061 RBX: 0000000000000308 RCX: ffff88807faf0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffffc900036b7647 R09: 1ffff920006d6ec8
R10: dffffc0000000000 R11: ffffffff883479d0 R12: dffffc0000000000
R13: ffff8880798113b8 R14: 0000000000000000 R15: ffff8880798108d8
FS:  000055558749c400(0000) GS:ffff888124cca000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbf685aaa20 CR3: 0000000020716000 CR4: 0000000000350ef0
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: 0033:0x7fbf6855bcf9
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff0240de98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fbf6855bcf9
RDX: 0000200000000100 RSI: 0000000040146f2c RDI: 0000000000000004
RBP: 00000000000f4240 R08: 0000000000000000 R09: 0000000000000009
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000140fe
R13: 00007fff0240deac R14: 00007fff0240dec0 R15: 00007fff0240deb0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:mxl111sf_ep6_streaming_ctrl+0x2e/0x2e0 drivers/media/usb/dvb-usb-v2/mxl111sf.c:348
Code: 55 41 57 41 56 41 54 53 89 f5 49 89 fe 49 bc 00 00 00 00 00 fc ff df e8 10 62 93 f9 49 8d 9e 08 03 00 00 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 53 66 03 fa 48 8b 1b 48 83 c3 38
RSP: 0018:ffffc900036b7b30 EFLAGS: 00010212
RAX: 0000000000000061 RBX: 0000000000000308 RCX: ffff88807faf0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffffc900036b7647 R09: 1ffff920006d6ec8
R10: dffffc0000000000 R11: ffffffff883479d0 R12: dffffc0000000000
R13: ffff8880798113b8 R14: 0000000000000000 R15: ffff8880798108d8
FS:  000055558749c400(0000) GS:ffff888124dca000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff0240ce50 CR3: 0000000020716000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
   0:	55                   	push   %rbp
   1:	41 57                	push   %r15
   3:	41 56                	push   %r14
   5:	41 54                	push   %r12
   7:	53                   	push   %rbx
   8:	89 f5                	mov    %esi,%ebp
   a:	49 89 fe             	mov    %rdi,%r14
   d:	49 bc 00 00 00 00 00 	movabs $0xdffffc0000000000,%r12
  14:	fc ff df
  17:	e8 10 62 93 f9       	call   0xf993622c
  1c:	49 8d 9e 08 03 00 00 	lea    0x308(%r14),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 53 66 03 fa       	call   0xfa03668c
  39:	48 8b 1b             	mov    (%rbx),%rbx
  3c:	48 83 c3 38          	add    $0x38,%rbx

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/26 21:09 upstream 6812ce4e4379 a3c7249d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root general protection fault in mxl111sf_ep6_streaming_ctrl
2026/09/26 14:00 upstream 6812ce4e4379 a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root general protection fault in mxl111sf_ep6_streaming_ctrl
* Struck through repros no longer work on HEAD.