From: Christoph Hellwig <hch@lst.de>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, tony.luck@intel.com,
ralf@linux-mips.org, kyle@mcmartin.ca, benh@kernel.crashing.org,
schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com,
davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com,
hpa@zytor.com, viro@zeniv.linux.org.uk
Subject: Re: [PATCH 4/6] improve sys_personality for compat architectures
Date: Tue, 2 Feb 2010 17:31:45 +0100 [thread overview]
Message-ID: <20100202163145.GA30659@lst.de> (raw)
In-Reply-To: <201002021536.51928.arnd@arndb.de>
On Tue, Feb 02, 2010 at 03:36:51PM +0100, Arnd Bergmann wrote:
> > - return (long)old;
> > + return (long)(old == PER_LINUX32 ? PER_LINUX : old);
> > }
>
> What does this do for a native 64 bit process setting PER_LINUX32?
> It looks to me like it could never set it back to the original
> value, or am I missing something here?
>
> It's what the arch specific code does already, but it seems a bit
> strange anyway.
Indeed, this prevents a process from going back to 64bit. And while
the setarch tool in util-linux also allows going back to 64-bit the
typical use case seems to be going into 32-bit mode.
But if the consensus is that we should fix this properly I can
replace the patch with one introducing a compat_sys_personality
which only gets used for compat tasks.
next prev parent reply other threads:[~2010-02-02 16:32 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-01 18:56 [PATCH 4/6] improve sys_personality for compat architectures Christoph Hellwig
2010-02-02 14:36 ` Arnd Bergmann
2010-02-02 16:31 ` Christoph Hellwig [this message]
2010-02-03 17:06 ` Arnd Bergmann
2010-02-03 17:13 ` David Miller
2010-02-03 20:04 ` H. Peter Anvin
2010-02-04 7:38 ` Arnd Bergmann
2010-02-04 16:00 ` Christoph Hellwig
2010-03-05 19:49 ` Andrew Morton
2010-03-09 12:58 ` Christoph Hellwig
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