From: Thomas Renninger <trenn@suse.de>
To: Valdis.Kletnieks@vt.edu
Cc: roel kluin <roel.kluin@gmail.com>,
ak@linux.intel.com, lenb@kernel.org, linux-acpi@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH ?] ACPI: pr->id is unsigned
Date: Tue, 16 Sep 2008 10:45:31 +0200 [thread overview]
Message-ID: <200809161045.35078.trenn@suse.de> (raw)
In-Reply-To: <128370.1221510405@turing-police.cc.vt.edu>
On Monday 15 September 2008 22:26:45 Valdis.Kletnieks@vt.edu wrote:
> On Mon, 15 Sep 2008 21:32:20 EDT, roel kluin said:
> > since pr->id is unsigned, shouldn't something like
> > the patch below be applied?
> >
> > + BUG_ON((pr->id >= nr_cpu_ids) || ((unsigned long)pr->id < 0));
>
> Under what conditions will the clause "(unsigned long)pr->id < 0)" be true,
> and when will it be false? What will any sane optimizing compiler do?
>
> And *sometimes*, the *real* bug is that pr->id should be a signed quantity,
> not an unsigned one, and the cast is just papering over the issue.
>
> In other words, the original line is almost certainly buggy. However, this
> isn't the right fix. Somebody who actually understands the code will have
> to decide what *should* be happening here (that's beyond my understanding
> of that code)...
Just removing "pr->id < 0" condition should be the right fix.
For such an easy patch in the ACPI subsystem it's enough to only post to
the linux-acpi mailing list, no need to bother the whole world.
Thanks for finding this, do you mind to repost a new version?
Thomas
prev parent reply other threads:[~2008-09-16 8:45 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-16 1:32 [PATCH ?] ACPI: pr->id is unsigned roel kluin
2008-09-15 20:26 ` Valdis.Kletnieks
2008-09-16 8:45 ` Thomas Renninger [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=200809161045.35078.trenn@suse.de \
--to=trenn@suse.de \
--cc=Valdis.Kletnieks@vt.edu \
--cc=ak@linux.intel.com \
--cc=lenb@kernel.org \
--cc=linux-acpi@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=roel.kluin@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).