From: Jiri Slaby <jirislaby@kernel.org>
To: Dianne Skoll <dianne@skoll.ca>,
linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: N_HDLC line discipline: Race condition
Date: Wed, 15 May 2024 12:33:24 +0200 [thread overview]
Message-ID: <c937cd80-ecd5-4d41-ad72-668661898039@kernel.org> (raw)
In-Reply-To: <20240425140127.6504ade1@gato.skoll.ca>
Hi,
On 25. 04. 24, 20:01, Dianne Skoll wrote:
> I have (somewhat) narrowed down when the kernel bug appeared by installing
> Debian 10, 11 and 12 in KVM virtual machines.
>
> The bug is NOT present in Debian 10, kernel version 4.19.67.
I can repro even with 4.19:
posix_openpt = 3
grantpt(3) = 0
unlockpt(3) = 0
ptsname(3) = /dev/pts/2
open(/dev/pts/2) = 4
ioctl(3, TIOCSETD) = 0
ioctl(4, TIOCSETD) = 0
write(3, Hello , 6) = 6
write(3, world, 5) = 5
read(4, buf, 2048) = 6
buf = |Hello |
read(4, buf, 2048) = 5
buf = |world|
read(4, buf, 2048) = -1
write(3, Hello , 6) = 6
write(3, world, 5) = 5
read(4, buf, 2048) = 11
buf = |Hello world|
HAHA! Try #2: The two writes were combined in a single read!
Could you recheck?
> The bug IS present in Debian 11, kernel version 5.10.209
>
> The bug IS present in Debian 12, kernel version 6.1.85
>
> So I guess it was introduced sometime between 4.19.67 and 5.10.209. I'll
> take a look to see if I can do a git bisect.
Were you able to do so?
thanks,
--
js
suse labs
next prev parent reply other threads:[~2024-05-15 10:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-24 21:31 N_HDLC line discipline: Race condition Dianne Skoll
2024-04-25 18:01 ` Dianne Skoll
2024-05-15 10:33 ` Jiri Slaby [this message]
2024-05-15 13:42 ` Dianne Skoll
2024-05-15 15:44 ` Dianne Skoll
2024-05-21 10:47 ` Jiri Slaby
2024-05-21 14:15 ` Dianne Skoll
2024-05-23 8:01 ` Jiri Slaby
2024-05-23 12:44 ` Dianne Skoll
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