Re: Linux portability bugs

From: Chuck Ebbert
Date: Sun Dec 10 2006 - 23:49:41 EST


In-Reply-To: <a2705a960612012239j697f2799t27bec643f33c9e12@xxxxxxxxxxxxxx>

On Fri, 1 Dec 2006 22:39:01 -0800, mariusn wrote:

> I am a graduate student at University of Washington, building a tool
> automatically discover portability bugs in system-level code written
> in C. My definition of "portability" is at the data layout level,
> accounting for differences in alignment, padding, and generally layout
> policies on various platforms. E.g., one might perform a pointer cast
> that only works as intended when doubles are 4-byte aligned, which is
> the case with gcc/ia-32 (default options) but not with gcc/sparc (due
> to sparc's limited support for accessing doubles on non-8-byte
> boundaries).
>
> I am looking for advice on how/where to look for these kinds of bugs
> in the kernel and related software. This (dated) document
> (http://netwinder.osuosl.org/users/b/brianbr/public_html/alignment.html
> ) describes exactly these sorts of issues in the context of Linux/ARM
> and mentions things like the kernel, binutils, cpio, X11, Orbit, as
> sources of these sorts of bugs. I am having a bit of a hard time
> locating change logs and otherwise related information on where these
> bugs occurred, patches that addressed them, etc.

Look for "compat" in the patch title and comments, like this one:

http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=46c5ea3c9ae7fbc6e52a13c92e59d4fc7f4ca80a
--
Chuck
"Even supernovas have their duller moments."

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