From: Greg KH <gregkh@linuxfoundation.org>
To: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: linux-kernel@vger.kernel.org, Kees Cook <keescook@chromium.org>,
"David S. Miller" <davem@davemloft.net>,
linux-crypto@vger.kernel.org, netdev@vger.kernel.org,
linux-usb@vger.kernel.org
Subject: Re: [PATCH] treewide: Replace zero-length arrays with flexible-array member
Date: Tue, 11 Feb 2020 10:32:29 -0800 [thread overview]
Message-ID: <20200211183229.GA1938663@kroah.com> (raw)
In-Reply-To: <20200211174126.GA29960@embeddedor>
On Tue, Feb 11, 2020 at 11:41:26AM -0600, Gustavo A. R. Silva wrote:
> The current codebase makes use of the zero-length array language
> extension to the C90 standard, but the preferred mechanism to declare
> variable-length types such as these ones is a flexible array member[1][2],
> introduced in C99:
>
> struct foo {
> int stuff;
> struct boo array[];
> };
>
> By making use of the mechanism above, we will get a compiler warning
> in case the flexible array does not occur last in the structure, which
> will help us prevent some kind of undefined behavior bugs from being
> unadvertenly introduced[3] to the codebase from now on.
>
> All these instances of code were found with the help of the following
> Coccinelle script:
>
> @@
> identifier S, member, array;
> type T1, T2;
> @@
>
> struct S {
> ...
> T1 member;
> T2 array[
> - 0
> ];
> };
>
> [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
> [2] https://github.com/KSPP/linux/issues/21
> [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
>
> NOTE: I'll carry this in my -next tree for the v5.6 merge window.
Why not carve this up into per-subsystem patches so that we can apply
them to our 5.7-rc1 trees and then you submit the "remaining" that don't
somehow get merged at that timeframe for 5.7-rc2?
thanks,
greg k-h
next prev parent reply other threads:[~2020-02-11 18:32 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-11 17:41 [PATCH] treewide: Replace zero-length arrays with flexible-array member Gustavo A. R. Silva
2020-02-11 18:32 ` Greg KH [this message]
2020-02-11 19:20 ` Gustavo A. R. Silva
2020-02-11 19:32 ` Kees Cook
2020-02-11 19:38 ` Greg KH
2020-02-11 19:54 ` Gustavo A. R. Silva
2020-02-11 20:12 ` Kees Cook
2020-02-11 20:30 ` Gustavo A. R. Silva
2020-02-11 19:35 ` Kees Cook
2020-02-11 20:16 ` Gustavo A. R. Silva
2020-02-12 8:00 ` Geert Uytterhoeven
2020-02-12 8:36 ` Kars de Jong
2020-02-13 11:09 ` Geert Uytterhoeven
2020-02-13 11:11 ` Ard Biesheuvel
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