general protection fault in keyspan_break_ctl

Status: upstream: reported C repro on 2026/10/20 05:37
Reported-by: syzbot+1b5083cc6d1661cbf5c4@syzkaller.appspotmail.com
First crash: 7d16h, last: 7d15h
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in keyspan_break_ctl prio:high usb 8 syz, C 43 24d 61d 26/29 upstream: reported C repro on 2026/08/27 18:53
linux-6.1 BUG: unable to handle kernel paging request in keyspan_break_ctl 8 syz, C 10 7d12h 16d 0/3 upstream: reported C repro on 2026/10/11 16:26
linux-6.6 general protection fault in keyspan_break_ctl 2 syz, C 7 16d 16d 0/2 upstream: reported C repro on 2026/10/11 02:07

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000013: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]
CPU: 0 PID: 4452 Comm: syz.2.19 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:keyspan_break_ctl+0x7f/0xc0 drivers/usb/serial/keyspan.c:-1
Code: 67 3e 9e fb 41 be 9c 00 00 00 4d 03 37 bf ff ff ff ff 89 ee e8 b2 fc 58 fb 45 31 ff 83 fd ff 41 0f 94 c7 4c 89 f0 48 c1 e8 03 <42> 0f b6 04 20 84 c0 75 15 45 89 3e 48 89 df 31 f6 5b 41 5c 41 5e
RSP: 0018:ffffc9000343fe00 EFLAGS: 00010203
RAX: 0000000000000013 RBX: ffff88807167e000 RCX: ffff88802a791dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000ffffffff
RBP: 0000000000000000 R08: ffffffff91015177 R09: 1ffffffff2202a2e
R10: dffffc0000000000 R11: fffffbfff2202a2f R12: dffffc0000000000
R13: dffffc0000000000 R14: 000000000000009c R15: 0000000000000000
FS:  000055557dc9e500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f863698fa08 CR3: 000000005bd4f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 serial_break+0xaf/0xf0 drivers/usb/serial/usb-serial.c:538
 send_break+0x212/0x2f0 drivers/tty/tty_io.c:2516
 tty_ioctl+0xb41/0xc30 drivers/tty/tty_io.c:-1
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1792b46559
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd7c800ec8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f1792dcdfa0 RCX: 00007f1792b46559
RDX: 0000000000000007 RSI: 0000000000005425 RDI: 0000000000000004
RBP: 00007f1792bddad8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1792dcdfac R14: 00007f1792dcdfa0 R15: 00007f1792dcdfa0
 </TASK>
Modules linked in:
---[ end trace c21756b5862f1416 ]---
RIP: 0010:keyspan_break_ctl+0x7f/0xc0 drivers/usb/serial/keyspan.c:-1
Code: 67 3e 9e fb 41 be 9c 00 00 00 4d 03 37 bf ff ff ff ff 89 ee e8 b2 fc 58 fb 45 31 ff 83 fd ff 41 0f 94 c7 4c 89 f0 48 c1 e8 03 <42> 0f b6 04 20 84 c0 75 15 45 89 3e 48 89 df 31 f6 5b 41 5c 41 5e
RSP: 0018:ffffc9000343fe00 EFLAGS: 00010203
RAX: 0000000000000013 RBX: ffff88807167e000 RCX: ffff88802a791dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000ffffffff
RBP: 0000000000000000 R08: ffffffff91015177 R09: 1ffffffff2202a2e
R10: dffffc0000000000 R11: fffffbfff2202a2f R12: dffffc0000000000
R13: dffffc0000000000 R14: 000000000000009c R15: 0000000000000000
FS:  000055557dc9e500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f863698fa08 CR3: 000000005bd4f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	67 3e 9e             	addr32 ds sahf
   3:	fb                   	sti
   4:	41 be 9c 00 00 00    	mov    $0x9c,%r14d
   a:	4d 03 37             	add    (%r15),%r14
   d:	bf ff ff ff ff       	mov    $0xffffffff,%edi
  12:	89 ee                	mov    %ebp,%esi
  14:	e8 b2 fc 58 fb       	call   0xfb58fccb
  19:	45 31 ff             	xor    %r15d,%r15d
  1c:	83 fd ff             	cmp    $0xffffffff,%ebp
  1f:	41 0f 94 c7          	sete   %r15b
  23:	4c 89 f0             	mov    %r14,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 20       	movzbl (%rax,%r12,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	75 15                	jne    0x48
  33:	45 89 3e             	mov    %r15d,(%r14)
  36:	48 89 df             	mov    %rbx,%rdi
  39:	31 f6                	xor    %esi,%esi
  3b:	5b                   	pop    %rbx
  3c:	41 5c                	pop    %r12
  3e:	41 5e                	pop    %r14

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/20 06:18 linux-5.15.y 792fbe1537d8 72cdc28d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in keyspan_break_ctl
2026/10/20 05:36 linux-5.15.y 792fbe1537d8 72cdc28d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in keyspan_break_ctl
* Struck through repros no longer work on HEAD.