BUG: unable to handle kernel paging request in keyspan_break_ctl

Status: upstream: reported C repro on 2026/10/11 16:26
Reported-by: syzbot+40bb1b64d79808a9a165@syzkaller.appspotmail.com
First crash: 1d10h, last: 1d08h
▶ ▼ Similar bugs (2)
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 9d10h 46d 24/29 upstream: reported C repro on 2026/08/27 18:53
linux-6.6 general protection fault in keyspan_break_ctl 2 syz, C 7 1d09h 2d00h 0/2 upstream: reported C repro on 2026/10/11 02:07

Sample crash report:
Unable to handle kernel paging request at virtual address dfff800000000013
KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]
Mem abort info:
  ESR = 0x0000000096000006
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x06: level 2 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000006
  CM = 0, WnR = 0
[dfff800000000013] address between user and kernel address ranges
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 4544 Comm: syz.1.22 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2026
pstate: 02400005 (nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : keyspan_break_ctl+0x80/0xcc drivers/usb/serial/keyspan.c:-1
lr : keyspan_break_ctl+0x6c/0xcc drivers/usb/serial/keyspan.c:609
sp : ffff800021ee7c20
x29: ffff800021ee7c20 x28: 0000000000000000 x27: 1fffe0001bf9f000
x26: dfff800000000000 x25: ffff80000db3de60 x24: 1fffe0001ba7e203
x23: ffff0000dd3f1018 x22: 0000000000000000 x21: dfff800000000000
x20: 0000000000000000 x19: ffff0000ddabe000 x18: 1fffe00033c1c97e
x17: ffff80001641d000 x16: ffff8000082dd38c x15: 0000000040000000
x14: 0000000000000010 x13: 1ffff000043dcf28 x12: 0000000000000000
x11: ff0080000db9c100 x10: 0000000000000007 x9 : 0000000000000013
x8 : 000000000000009c x7 : 0000000000000000 x6 : 000000000000003f
x5 : 0000000000000040 x4 : 0000000000000000 x3 : 0000000000000000
x2 : 0000000000000006 x1 : 0000000000000000 x0 : 00000000ffffffff
Call trace:
 keyspan_break_ctl+0x80/0xcc drivers/usb/serial/keyspan.c:-1
 serial_break+0xb0/0xf8 drivers/usb/serial/usb-serial.c:541
 send_break+0x1d4/0x288 drivers/tty/tty_io.c:2484
 tty_ioctl+0xc3c/0xd88 drivers/tty/tty_io.c:-1
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: 3100069f d343fd09 1200090a 11000d4a (38f56929) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	3100069f 	cmn	w20, #0x1
   4:	d343fd09 	lsr	x9, x8, #3
   8:	1200090a 	and	w10, w8, #0x7
   c:	11000d4a 	add	w10, w10, #0x3
* 10:	38f56929 	ldrsb	w9, [x9, x21] <-- trapping instruction

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/11 17:15 linux-6.1.y a500ba24937a 4f92358f .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in keyspan_break_ctl
2026/10/11 16:47 linux-6.1.y a500ba24937a 4f92358f .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in keyspan_break_ctl
2026/10/11 16:25 linux-6.1.y a500ba24937a 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in keyspan_break_ctl
2026/10/11 18:25 linux-6.1.y a500ba24937a 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan general protection fault in keyspan_break_ctl
2026/10/11 18:25 linux-6.1.y a500ba24937a 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan general protection fault in keyspan_break_ctl
* Struck through repros no longer work on HEAD.