linux-kernel - Re: [patch 2/2] x86, fpu: lazy allocation of FPU area

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Message-ID: <20080304175528.GD28006@linux-os.sc.intel.com>
Date:	Tue, 4 Mar 2008 09:55:28 -0800
From:	Suresh Siddha <suresh.b.siddha@...el.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Suresh Siddha <suresh.b.siddha@...el.com>,
	Christoph Hellwig <hch@...radead.org>, hpa@...or.com,
	tglx@...utronix.de, andi@...stfloor.org,
	linux-kernel@...r.kernel.org,
	Arjan van de Ven <arjan@...ux.intel.com>
Subject: Re: [patch 2/2] x86, fpu: lazy allocation of FPU area - v3

On Tue, Mar 04, 2008 at 11:32:20AM +0100, Ingo Molnar wrote:
> 
> * Suresh Siddha <suresh.b.siddha@...el.com> wrote:
> 
> > On Mon, Mar 03, 2008 at 08:20:12PM -0500, Christoph Hellwig wrote:
> > > On Mon, Mar 03, 2008 at 03:02:46PM -0800, Suresh Siddha wrote:
> > > > +	/*
> > > > +	 * Memory allocation at the first usage of the FPU and other state.
> > > > +	 */
> > > > +	if (!tsk->thread.xstate)
> > > > +		tsk->thread.xstate = kmem_cache_alloc(task_xstate_cachep, GFP_KERNEL);
> > >
> > >  Also don't we need some kind of error handling here?
> > 
> > Currently it uses SLAB_PANIC.
> 
> but SLAB_PANIC only covers kmem_cache_create() failures. 
> 
> kmem_cache_alloc() can fail (return NULL) and not handling it is a bug.

oops. you are correct. Will send a sigsegv in the failure case then. Thanks.
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