From: Peter Zijlstra <peterz@infradead.org>
To: Stephane Eranian <eranian@google.com>
Cc: linux-kernel@vger.kernel.org, asharma@fb.com, mingo@elte.hu
Subject: Re: [PATCH] perf/x86: fix broken LBR fixup code
Date: Mon, 11 Jun 2012 15:47:44 +0200 [thread overview]
Message-ID: <1339422464.30462.17.camel@twins> (raw)
In-Reply-To: <20120611134426.GA7542@quad>
On Mon, 2012-06-11 at 15:44 +0200, Stephane Eranian wrote:
> I noticed that the LBR fixups were not working anymore
> on programs where they used to. I tracked this down to
> a recent change to copy_from_user_nmi().
>
> commit db0dc75d6403b6663c0eab4c6ccb672eb9b2ed72
> Author: Arun Sharma <asharma@fb.com>
> Date: Fri Apr 20 15:41:36 2012 -0700
>
> perf/x86: Check user address explicitly in copy_from_user_nmi()
>
> This commit added a call to __range_not_ok() to the
> copy_from_user_nmi() routine. The problem is that the logic
> of the test must be reversed. __range_not_ok() returns 0 if the
> range is VALID. We want to return early from copy_from_user_nmi()
> if the range is NOT valid.
D'0h.. Thanks!
next prev parent reply other threads:[~2012-06-11 13:47 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-11 13:44 [PATCH] perf/x86: fix broken LBR fixup code Stephane Eranian
2012-06-11 13:47 ` Peter Zijlstra [this message]
2012-06-11 19:41 ` Arun Sharma
2012-06-14 8:40 ` [tip:perf/urgent] perf/x86: Fix " tip-bot for Stephane Eranian
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=1339422464.30462.17.camel@twins \
--to=peterz@infradead.org \
--cc=asharma@fb.com \
--cc=eranian@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
/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