From: David Laight <David.Laight@ACULAB.COM>
To: 'Mathieu Desnoyers' <mathieu.desnoyers@efficios.com>,
Kees Cook <keescook@chromium.org>
Cc: William Cohen <wcohen@redhat.com>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
Laura Abbott <labbott@redhat.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Russell King <rmk+kernel@armlinux.org.uk>,
linux-kernel <linux-kernel@vger.kernel.org>,
"lttng@reliableembeddedsystems.com"
<lttng@reliableembeddedsystems.com>,
lttng-dev <lttng-dev@lists.lttng.org>
Subject: RE: optimized kprobes illegal instructions in v4.19 stable kernels
Date: Wed, 6 Feb 2019 11:48:44 +0000 [thread overview]
Message-ID: <76948cf5011e454494107cea61c6930c@AcuMS.aculab.com> (raw)
In-Reply-To: <342740659.2887.1549307721609.JavaMail.zimbra@efficios.com>
From: Mathieu Desnoyers
> Sent: 04 February 2019 19:15
> I notice this commit as a possible culprit of the illegal instructions my lttng
> users are noticing on arm32 when using kprobes on a v4.19.13 Linux kernel
> in a Yocto environment [1]. They were able to reproduce the issue with perf
> as well.
>
> commit e46daee53bb50bde38805f1823a182979724c229
> Author: Kees Cook <keescook@chromium.org>
> Date: Tue Oct 30 22:12:56 2018 +0100
>
> ARM: 8806/1: kprobes: Fix false positive with FORTIFY_SOURCE
>
> I *think* the intent there was to do
>
> - memcpy(code, &optprobe_template_entry,
> + memcpy(code, (unsigned long *)&optprobe_template_entry,
>
> But if you look at the commit, the "&" seems to have been stripped away,
> which happens to change the behavior significantly.
Which is why you shouldn't add casts to shut up compiler warnings ....
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
prev parent reply other threads:[~2019-02-06 11:48 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-04 19:15 BUG: " Mathieu Desnoyers
2019-02-05 15:06 ` Kees Cook
2019-02-06 4:41 ` Masami Hiramatsu
2019-02-18 12:26 ` Greg KH
2019-02-18 14:11 ` Masami Hiramatsu
2019-02-18 14:55 ` Mathieu Desnoyers
2019-02-21 20:02 ` Mathieu Desnoyers
2019-02-22 0:10 ` Russell King - ARM Linux admin
2019-02-22 0:17 ` Mathieu Desnoyers
2019-02-22 6:25 ` Greg Kroah-Hartman
2019-02-22 8:29 ` Greg Kroah-Hartman
2019-02-22 20:18 ` Mathieu Desnoyers
2019-02-06 11:48 ` David Laight [this message]
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