From: Jani Nikula <jani.nikula@intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Arnd Bergmann <arnd@arndb.de>
Cc: "Sudip Mukherjee" <sudipm.mukherjee@gmail.com>,
"Russell King" <linux@armlinux.org.uk>,
"Viresh Kumar" <vireshk@kernel.org>,
"Shiraz Hashim" <shiraz.linux.kernel@gmail.com>,
"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
"Maxime Ripard" <mripard@kernel.org>,
"Thomas Zimmermann" <tzimmermann@suse.de>,
"David Airlie" <airlied@linux.ie>,
"Daniel Vetter" <daniel@ffwll.ch>,
dri-devel <dri-devel@lists.freedesktop.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"Linux ARM" <linux-arm-kernel@lists.infradead.org>,
"SoC Team" <soc@kernel.org>
Subject: Re: mainline build failure due to f1e4c916f97f ("drm/edid: add EDID block count and size helpers")
Date: Mon, 30 May 2022 12:31:17 +0300 [thread overview]
Message-ID: <87a6aztli2.fsf@intel.com> (raw)
In-Reply-To: <CAHk-=whfmwzjF4eBPYS6pHFqHVzJF3m=2h=gRWSRyHks8V=ABA@mail.gmail.com>
On Sat, 28 May 2022, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Sat, May 28, 2022 at 11:59 AM Arnd Bergmann <arnd@arndb.de> wrote:
>>
>> It's CONFIG_ARM_AEABI, which is normally set everywhere. Without this
>> option, you the kernel is built for the old 'OABI' that forces all non-packed
>> struct members to be at least 16-bit aligned.
>
> Looks like forced word (32 bit) alignment to me.
>
> I wonder how many other structures that messes up, but I committed the
> EDID fix for now.
Thanks for the fix, and the thorough commit message!
> This has presumably been broken for a long time, but maybe the
> affected targets don't typically use EDID and kernel modesetting, and
> only use some fixed display setup instead.
>
> Those structure definitions go back a _loong_ time (from a quick 'git
> blame' I see November 2008).
>
> But despite that, I did not mark my fix 'cc:stable' because I don't
> know if any of those machines affected by this bad arm ABI issue could
> possibly care.
>
> At least my tree hopefully now builds on them, with the BUILD_BUG_ON()
> that uncovered this.
Indeed the bug is ancient. I just threw in the BUILD_BUG_ON() on a whim
as an extra sanity check when doing pointer arithmetics on struct edid
*.
If there are affected machines, buffer overflows are the real danger due
to edid->extensions indicating the number of extensions.
BR,
Jani.
--
Jani Nikula, Intel Open Source Graphics Center
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-05-30 9:33 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <YpCUzStDnSgQLNFN@debian>
[not found] ` <CAHk-=wg0uGAX5DYZq+tY2KeUAR8DtR91YE1y9CkPMKkKOyE4jg@mail.gmail.com>
[not found] ` <CADVatmNGPbSdRNQuwJEWAaPtqb3vBYRjvsuBpoRUnhEHj=X5GQ@mail.gmail.com>
[not found] ` <CAHk-=wisQd8yiPX=SsK3eFiakKo713hq4SyqPWsJ-oyAmLFefQ@mail.gmail.com>
[not found] ` <YpIR67FMtTGCwARZ@debian>
[not found] ` <CAHk-=wjuyHE=1wLgHncub8FfgeyYqfWYsy4-YrhAvq9991h_Aw@mail.gmail.com>
2022-05-28 18:08 ` mainline build failure due to f1e4c916f97f ("drm/edid: add EDID block count and size helpers") Linus Torvalds
2022-05-28 18:58 ` Arnd Bergmann
2022-05-28 20:31 ` Linus Torvalds
2022-05-28 21:08 ` Arnd Bergmann
2022-05-30 9:31 ` Jani Nikula [this message]
2022-05-30 9:33 ` Jani Nikula
2022-05-30 12:43 ` Arnd Bergmann
2022-05-30 13:10 ` Jani Nikula
2022-05-30 13:35 ` Arnd Bergmann
2022-05-30 14:08 ` Jani Nikula
2022-05-30 14:26 ` Arnd Bergmann
2022-05-31 6:26 ` Julia Lawall
2022-05-31 8:04 ` Arnd Bergmann
2022-05-31 16:41 ` Linus Torvalds
2022-06-01 22:28 ` Keisuke Nishimura
2022-06-02 1:08 ` Linus Torvalds
2022-06-02 7:38 ` Arnd Bergmann
2022-06-02 11:21 ` Tetsuo Handa
2022-06-02 12:11 ` Arnd Bergmann
2022-06-02 13:18 ` Ard Biesheuvel
2022-06-02 12:19 ` Christoph Hellwig
2022-06-06 10:51 ` Keisuke Nishimura
2022-05-30 16:56 ` Russell King (Oracle)
2022-05-30 16:54 ` Russell King (Oracle)
2022-05-30 16:53 ` Russell King (Oracle)
2022-05-28 20:32 ` Russell King (Oracle)
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