From: Valdis.Kletnieks@vt.edu
To: roel kluin <roel.kluin@gmail.com>
Cc: 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: Mon, 15 Sep 2008 16:26:45 -0400 [thread overview]
Message-ID: <128370.1221510405@turing-police.cc.vt.edu> (raw)
In-Reply-To: Your message of "Mon, 15 Sep 2008 21:32:20 EDT." <48CF0CA4.3090701@gmail.com>
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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)...
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next prev parent reply other threads:[~2008-09-15 20:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-16 1:32 roel kluin
2008-09-15 20:26 ` Valdis.Kletnieks [this message]
2008-09-16 8:45 ` Thomas Renninger
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