* Re: [syzbot] [usb?] general protection fault in keyspan_break_ctl
2026-09-03 2:24 [PATCH] tty: fix break race Adriano Cordova
@ 2026-09-03 2:41 ` syzbot
0 siblings, 0 replies; 2+ messages in thread
From: syzbot @ 2026-09-03 2:41 UTC (permalink / raw)
To: adrianox, johan, linux-kernel, stable, syzkaller-bugs
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
general protection fault in keyspan_break_ctl
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: 6463 Comm: syz.3.20 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 24 67 42 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:ffffc9000334fca8 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffffff87c9835c
RDX: 0000000000000013 RSI: 00000000ffffffff RDI: 000000000000009c
RBP: ffff888059412000 R08: 0000000000000005 R09: 00000000ffffffff
R10: 00000000ffffffff R11: 0000000000000000 R12: 0000000000000000
R13: ffff888038a76e00 R14: ffff88802aef6020 R15: ffff88802aef60c8
FS: 00007f62980d46c0(0000) GS:ffff8880d5e61000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f41412c8d58 CR3: 0000000025cea000 CR4: 0000000000352ef0
Call Trace:
<TASK>
serial_break+0xcb/0x160 drivers/usb/serial/usb-serial.c:538
send_break drivers/tty/tty_io.c:2456 [inline]
send_break+0x194/0x3b0 drivers/tty/tty_io.c:2442
tty_ioctl+0xa2f/0x1640 drivers/tty/tty_io.c:2737
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl fs/ioctl.c:583 [inline]
__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f629719e0d9
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:00007f62980d4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f6297425fa0 RCX: 00007f629719e0d9
RDX: 0000000000000000 RSI: 0000000000005425 RDI: 0000000000000004
RBP: 00007f6297235024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6297426038 R14: 00007f6297425fa0 R15: 00007ffcf04a40e8
</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 24 67 42 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:ffffc9000334fca8 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffffff87c9835c
RDX: 0000000000000013 RSI: 00000000ffffffff RDI: 000000000000009c
RBP: ffff888059412000 R08: 0000000000000005 R09: 00000000ffffffff
R10: 00000000ffffffff R11: 0000000000000000 R12: 0000000000000000
R13: ffff888038a76e00 R14: ffff88802aef6020 R15: ffff88802aef60c8
FS: 00007f62980d46c0(0000) GS:ffff8880d5d61000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055aeb7ddb480 CR3: 0000000025cea000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess), 2 bytes skipped:
0: ff ljmp (bad)
1: e8 24 67 42 fa call 0xfa42672a
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
Tested on:
commit: 940de590 Merge tag 'hardening-v7.3-rc2' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10641f79580000
kernel config: https://syzkaller.appspot.com/x/.config?x=8c5c3949d762a91f
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
patch: https://syzkaller.appspot.com/x/patch.diff?x=10f81f79580000
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [syzbot] [usb?] general protection fault in keyspan_break_ctl
[not found] <6a9087a4.4d659fcc.734b4.0013.GAE@google.com>
@ 2026-09-03 14:55 ` syzbot
0 siblings, 0 replies; 2+ messages in thread
From: syzbot @ 2026-09-03 14:55 UTC (permalink / raw)
To: adrianox, gregkh, jirislaby, johan, kartikey406, linux-kernel,
linux-serial, linux-usb, stable, syzkaller-bugs
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.
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2026-09-03 14:55 UTC | newest]
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[not found] <6a9087a4.4d659fcc.734b4.0013.GAE@google.com>
2026-09-03 14:55 ` [syzbot] [usb?] general protection fault in keyspan_break_ctl syzbot
2026-09-03 2:24 [PATCH] tty: fix break race Adriano Cordova
2026-09-03 2:41 ` [syzbot] [usb?] general protection fault in keyspan_break_ctl syzbot
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