general protection fault in keyspan_break_ctl

Status: upstream: reported C repro on 2026/08/27 18:53
Subsystems: usb
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+473d7477c523b41d4046@syzkaller.appspotmail.com
First crash: 10d, last: 1d03h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
ba2efeaa assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ general protection fault in keyspan_break_ctl 2026/08/26 00:00 2026/08/26 00:00 2026/08/26 00:08 ee98d2fd
Discussions (3)
Title Replies (including bot) Last reply
[PATCH] USB: serial: fix ioctl hangup race 1 (1) 2026/09/03 16:31
[syzbot] [usb?] general protection fault in keyspan_break_ctl 1 (7) 2026/09/03 14:55
[PATCH v2 0/2] tty: fix break race 4 (4) 2026/09/03 06:22
Last patch testing requests (4)
Created Duration User Patch Repo Result
2026/09/03 03:42 19m adrianox@gmail.com patch upstream OK job log log
2026/09/03 03:25 14m adrianox@gmail.com upstream report job log log
2026/09/03 02:25 14m adrianox@gmail.com patch upstream report job log log
2026/08/28 01:28 22m kartikey406@gmail.com patch upstream error job log

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000013: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]
CPU: 3 UID: 0 PID: 6034 Comm: syz.1.25 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:keyspan_break_ctl+0x8e/0xe0 drivers/usb/serial/keyspan.c:608
Code: ff ff ff e8 74 88 43 fa 83 fb ff 48 b8 00 00 00 00 00 fc ff df 49 8d bc 24 9c 00 00 00 0f 94 c3 48 89 fa 0f b6 db 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 1d 41
RSP: 0018:ffffc90004bafc50 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff87c7ae2c
RDX: 0000000000000013 RSI: 00000000ffffffff RDI: 000000000000009c
RBP: ffff888069322000 R08: 0000000000000005 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88802abe3020 R14: ffff88802abe30c8 R15: 0000000000000007
FS:  0000000000000000(0000) GS:ffff888096c67000(0063) knlGS:00000000566da480
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f715d600 CR3: 000000005e275000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 serial_break+0xcb/0x160 drivers/usb/serial/usb-serial.c:538
 send_break drivers/tty/tty_io.c:2458 [inline]
 send_break+0x2ec/0x370 drivers/tty/tty_io.c:2441
 tty_ioctl+0xa2c/0x1640 drivers/tty/tty_io.c:2733
 tty_compat_ioctl+0x87/0x420 drivers/tty/tty_io.c:2931
 __do_compat_sys_ioctl fs/ioctl.c:695 [inline]
 __se_compat_sys_ioctl fs/ioctl.c:638 [inline]
 __ia32_compat_sys_ioctl+0x2cf/0x360 fs/ioctl.c:638
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
 __do_fast_syscall_32+0x13a/0x8b0 arch/x86/entry/syscall_32.c:291
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf6fdefec
Code: Unable to access opcode bytes at 0xf6fdefc2.
RSP: 002b:00000000ff97a24c EFLAGS: 00000292 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000005425
RDX: 0000000000000007 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:keyspan_break_ctl+0x8e/0xe0 drivers/usb/serial/keyspan.c:608
Code: ff ff ff e8 74 88 43 fa 83 fb ff 48 b8 00 00 00 00 00 fc ff df 49 8d bc 24 9c 00 00 00 0f 94 c3 48 89 fa 0f b6 db 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 1d 41
RSP: 0018:ffffc90004bafc50 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff87c7ae2c
RDX: 0000000000000013 RSI: 00000000ffffffff RDI: 000000000000009c
RBP: ffff888069322000 R08: 0000000000000005 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88802abe3020 R14: ffff88802abe30c8 R15: 0000000000000007
FS:  0000000000000000(0000) GS:ffff888096b67000(0063) knlGS:00000000566da480
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f72d9bcc CR3: 000000005e275000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	ff                   	ljmp   (bad)
   1:	e8 74 88 43 fa       	call   0xfa43887a
   6:	83 fb ff             	cmp    $0xffffffff,%ebx
   9:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  10:	fc ff df
  13:	49 8d bc 24 9c 00 00 	lea    0x9c(%r12),%rdi
  1a:	00
  1b:	0f 94 c3             	sete   %bl
  1e:	48 89 fa             	mov    %rdi,%rdx
  21:	0f b6 db             	movzbl %bl,%ebx
  24:	48 c1 ea 03          	shr    $0x3,%rdx
* 28:	0f b6 14 02          	movzbl (%rdx,%rax,1),%edx <-- trapping instruction
  2c:	48 89 f8             	mov    %rdi,%rax
  2f:	83 e0 07             	and    $0x7,%eax
  32:	83 c0 03             	add    $0x3,%eax
  35:	38 d0                	cmp    %dl,%al
  37:	7c 04                	jl     0x3d
  39:	84 d2                	test   %dl,%dl
  3b:	75 1d                	jne    0x5a
  3d:	41                   	rex.B

Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/03 15:24 upstream 940de590b839 d2e5fb95 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 general protection fault in keyspan_break_ctl
2026/09/03 14:55 upstream 940de590b839 d2e5fb95 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 general protection fault in keyspan_break_ctl
2026/08/25 08:47 upstream 818bebeb63dd 614e416a .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in keyspan_break_ctl
2026/08/25 01:27 upstream 818bebeb63dd 614e416a .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in keyspan_break_ctl
2026/08/25 01:09 upstream 818bebeb63dd 614e416a .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in keyspan_break_ctl
2026/08/25 04:58 linux-next 4b18edbd8e70 23caa175 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce general protection fault in keyspan_break_ctl
2026/08/25 01:28 linux-next 4b18edbd8e70 23caa175 .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce general protection fault in keyspan_break_ctl
2026/09/03 04:26 upstream 940de590b839 6a988719 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root general protection fault in keyspan_break_ctl
2026/08/25 07:34 upstream 818bebeb63dd 614e416a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in keyspan_break_ctl
2026/08/25 00:56 upstream 818bebeb63dd 614e416a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in keyspan_break_ctl
2026/08/25 00:47 linux-next 4b18edbd8e70 23caa175 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce general protection fault in keyspan_break_ctl
* Struck through repros no longer work on HEAD.