From: Paul Mackerras <paulus@samba.org>
To: Carl Love <cel@us.ibm.com>
Cc: linuxppc-dev <linuxppc-dev@ozlabs.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Maynard Johnson <maynardj@us.ibm.com>
Subject: Re: [PATCH] Fix for OProfile callgraph for Power 64 bit user apps
Date: Thu, 15 May 2008 20:47:06 +1000 [thread overview]
Message-ID: <18476.5290.709729.582063@cargo.ozlabs.ibm.com> (raw)
In-Reply-To: <1210183924.7726.28.camel@carll-linux-desktop>
Carl Love writes:
> The following patch fixes the 64 bit user code backtrace
> which currently may hang the system.
What exactly is wrong with it?
Having now taken a much closer look, I now don't think Nate Case's
patch addresses this, since it only affects constant size arguments
<= 8 to copy_{to,from}_user_inatomic.
However, I don't see why your patch fixes anything. It means we do
two access_ok calls and two __copy_from_user_inatomic calls, for 8
bytes, at sp and at sp + 16, rather than doing one access_ok and
__copy_from_user_inatomic for 24 bytes at sp. Why does that make any
difference (apart from being slower)?
Paul.
next prev parent reply other threads:[~2008-05-15 11:17 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-07 18:12 [PATCH] Fix for OProfile callgraph for Power 64 bit user apps Carl Love
2008-05-15 10:47 ` Paul Mackerras [this message]
2008-05-15 18:01 ` Carl Love
2008-05-16 16:32 ` Carl Love
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