From: syzbot <syzbot+473d7477c523b41d4046@syzkaller.appspotmail.com>
To: adrianox@gmail.com, gregkh@linuxfoundation.org,
jirislaby@kernel.org, johan@kernel.org, kartikey406@gmail.com,
linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
linux-usb@vger.kernel.org, stable@vger.kernel.org,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [usb?] general protection fault in keyspan_break_ctl
Date: Thu, 03 Sep 2026 07:55:52 -0700 [thread overview]
Message-ID: <6a998a78.e7659fcc.146146.000a.GAE@google.com> (raw)
In-Reply-To: <6a9087a4.4d659fcc.734b4.0013.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: 940de590b839 Merge tag 'hardening-v7.3-rc2' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13537c15580000
kernel config: https://syzkaller.appspot.com/x/.config?x=85bc5cc2fc7394d9
dashboard link: https://syzkaller.appspot.com/bug?extid=473d7477c523b41d4046
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
userspace arch: i386
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11f19f79580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15ed50f9580000
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-940de590.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f3f674f98efb/vmlinux-940de590.xz
kernel image: https://storage.googleapis.com/syzbot-assets/132222426e71/bzImage-940de590.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+473d7477c523b41d4046@syzkaller.appspotmail.com
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000013: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]
CPU: 0 UID: 0 PID: 6007 Comm: syz.2.19 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:ffffc900067ffc50 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff87c7ae2c
RDX: 0000000000000013 RSI: 00000000ffffffff RDI: 000000000000009c
RBP: ffff888013d9a000 R08: 0000000000000005 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88804a94d020 R14: ffff88804a94d0c8 R15: 0000000000000007
FS: 0000000000000000(0000) GS:ffff888096967000(0063) knlGS:0000000056ebd480
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000ffdb3ff0 CR3: 00000000529f7000 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: 0023:0xf702efec
Code: Unable to access opcode bytes at 0xf702efc2.
RSP: 002b:00000000ff93915c EFLAGS: 00000296 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:ffffc900067ffc50 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff87c7ae2c
RDX: 0000000000000013 RSI: 00000000ffffffff RDI: 000000000000009c
RBP: ffff888013d9a000 R08: 0000000000000005 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88804a94d020 R14: ffff88804a94d0c8 R15: 0000000000000007
FS: 0000000000000000(0000) GS:ffff888096a67000(0063) knlGS:0000000056ebd480
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f7349bcc CR3: 00000000529f7000 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
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
prev parent reply other threads:[~2026-09-03 14:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-27 18:53 [syzbot] [usb?] general protection fault in keyspan_break_ctl syzbot
2026-08-28 6:53 ` Johan Hovold
2026-09-03 14:55 ` syzbot [this message]
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