From: Aleksa Sarai <asarai@suse.de>
To: Tejun Heo <tj@kernel.org>, Nick Desaulniers <nick.desaulniers@gmail.com>
Cc: Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
cgroups@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Matthias Kaehlcke <mka@chromium.org>,
Michael Davidson <md@google.com>,
Greg Hackmann <ghackmann@google.com>,
android-llvm@google.com
Subject: Re: [PATCH] cgroup: reorder flexible array members of struct cgroup_root
Date: Sun, 22 Oct 2017 02:59:33 +1100 [thread overview]
Message-ID: <85d7f6eb-7869-551d-01b1-fa1712f4bd40@suse.de> (raw)
In-Reply-To: <20171021153253.GG1302522@devbig577.frc2.facebook.com>
> Here, not necessarily but I don't want to move it for a bogus reason.
> Why would we disallow embedding structs with flexible members in the
> middle when it can be done and is useful? If we want to discuss
> whether we want to avoid such usages in the kernel (but why?), sure,
> let's have that discussion but we can't decide that on "clang warns on
> it by default".
There was a talk a few years ago by the clang folks[1] saying that while
trying to build a kernel with clang, they discovered that several places
in the kernel uses "VLAIS" (variable Length Arrays In Structs") and
argued that this is a violation of the C specification, despite it being
a GNU extension. They also submitted several patches that removed this
code (even working around a user-space visible usage of VLAIS).
[1]:
https://www.linuxplumbersconf.org/2013/ocw/system/presentations/1221/original/VLAIS.pdf
--
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
https://www.cyphar.com/
next prev parent reply other threads:[~2017-10-21 15:59 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-17 6:33 Nick Desaulniers
2017-10-17 6:40 ` Nick Desaulniers
2017-10-17 6:45 ` Nick Desaulniers
2017-10-18 13:30 ` Tejun Heo
2017-10-20 7:15 ` Nick Desaulniers
2017-10-21 15:32 ` Tejun Heo
2017-10-21 15:59 ` Aleksa Sarai [this message]
2017-10-21 16:03 ` Tejun Heo
2017-10-21 19:08 ` Nick Desaulniers
2017-10-25 21:54 ` Matthias Kaehlcke
2017-10-26 14:32 ` Tejun Heo
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