Re: [PATCH 2/2] kmemleak: Ignore the aperture memory hole on x86_64

From: Ingo Molnar
Date: Mon Aug 31 2009 - 04:38:39 EST



* Catalin Marinas <catalin.marinas@xxxxxxx> wrote:

> On Sat, 2009-08-29 at 15:31 +0200, Ingo Molnar wrote:
> > * Catalin Marinas <catalin.marinas@xxxxxxx> wrote:
> > > --- a/arch/x86/kernel/aperture_64.c
> > > +++ b/arch/x86/kernel/aperture_64.c
> > > @@ -20,6 +20,7 @@
> > > #include <linux/bitops.h>
> > > #include <linux/ioport.h>
> > > #include <linux/suspend.h>
> > > +#include <linux/kmemleak.h>
> > > #include <asm/e820.h>
> > > #include <asm/io.h>
> > > #include <asm/iommu.h>
> > > @@ -94,6 +95,11 @@ static u32 __init allocate_aperture(void)
> > > * code for safe
> > > */
> > > p = __alloc_bootmem_nopanic(aper_size, aper_size, 512ULL<<20);
> > > + /*
> > > + * Kmemleak should not scan this block as it may not be mapped via the
> > > + * kernel direct mapping.
> > > + */
> > > + kmemleak_ignore(p);
> > > if (!p || __pa(p)+aper_size > 0xffffffff) {
> > > printk(KERN_ERR
> > > "Cannot allocate aperture memory hole (%p,%uK)\n",
> >
> > This sure does not look right for the rare but theoretically
> > possible !p case, does it?
>
> All the kmemleak_* callbacks check for (p && !IS_ERR(p)), just to
> simplify the calling site.

Indeed, i see. It's OK this way then.

Ingo
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