From: "H. Peter Anvin" <hpa@zytor.com>
To: mingo@redhat.com, hpa@zytor.com, levinsasha928@gmail.com,
linux-kernel@vger.kernel.org, tglx@linutronix.de
Cc: linux-tip-commits@vger.kernel.org
Subject: Re: [tip:timers/core] ntp: Fix integer overflow when setting time
Date: Thu, 15 Mar 2012 18:29:46 -0700 [thread overview]
Message-ID: <4F62978A.7000009@zytor.com> (raw)
In-Reply-To: <tip-a078c6d0e6288fad6d83fb6d5edd91ddb7b6ab33@git.kernel.org>
On 03/15/2012 02:53 PM, tip-bot for Sasha Levin wrote:
> Commit-ID: a078c6d0e6288fad6d83fb6d5edd91ddb7b6ab33
> Gitweb: http://git.kernel.org/tip/a078c6d0e6288fad6d83fb6d5edd91ddb7b6ab33
> Author: Sasha Levin <levinsasha928@gmail.com>
> AuthorDate: Thu, 15 Mar 2012 12:36:14 -0400
> Committer: Thomas Gleixner <tglx@linutronix.de>
> CommitDate: Thu, 15 Mar 2012 21:41:34 +0100
>
> ntp: Fix integer overflow when setting time
>
> 'long secs' is passed as divisor to div_s64, which accepts a 32bit
> divisor. On 64bit machines that value is trimmed back from 8 bytes
> back to 4, causing a divide by zero when the number is bigger than
> (1 << 32) - 1 and all 32 lower bits are 0.
>
> Use div64_long() instead.
>
Perhaps we should use the same kind of multiply-and-shift tricks we're
doing for jiffies conversion? If nothing else it ought to perform better.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2012-03-16 1:29 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-15 16:36 [PATCH 1/2] math: Introduce div64_long Sasha Levin
2012-03-15 16:36 ` [PATCH 2/2] ntp: Fix integer overflow when setting time Sasha Levin
2012-03-15 21:53 ` [tip:timers/core] " tip-bot for Sasha Levin
2012-03-16 1:29 ` H. Peter Anvin [this message]
2012-03-16 9:48 ` Thomas Gleixner
2012-03-16 14:42 ` H. Peter Anvin
2012-03-15 21:52 ` [tip:timers/core] math: Introduce div64_long tip-bot for Sasha Levin
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=4F62978A.7000009@zytor.com \
--to=hpa@zytor.com \
--cc=levinsasha928@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tip-commits@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=tglx@linutronix.de \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.