From: Jim Radford <radford@blackbean.org>
To: Nick Piggin <npiggin@suse.de>
Cc: linux-arch@vger.kernel.org,
linux-arm-kernel@lists.arm.linux.org.uk, rmk@arm.linux.org.uk,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [patch] mm: vmalloc fix lazy unmapping cache aliasing
Date: Wed, 19 Nov 2008 10:58:14 -0800 [thread overview]
Message-ID: <20081119185814.GA25025@blackbean.org> (raw)
In-Reply-To: <20081119045425.GB18697@wotan.suse.de>
On Wed, Nov 19, 2008 at 05:54:25AM +0100, Nick Piggin wrote:
> On Wed, Nov 19, 2008 at 05:53:38AM +0100, Nick Piggin wrote:
> > Jim Radford has reported that the vmap subsystem rewrite was sometimes causing
> > his VIVT ARM system to behave strangely (seemed like going into infinite loops
> > trying to fault in pages to userspace).
> > We determined that the problem was most likely due to a cache aliasing issue.
> > flush_cache_vunmap was only being called at the moment the page tables were
> > to be taken down, however with lazy unmapping, this can happen after the page
> > has subsequently been freed and allocated for something else. The dangling
> > alias may still have dirty data attached to it.
> > The fix for this problem is to do the cache flushing when the caller has
> > called vunmap -- it would be a bug for them to write anything else to the
> > mapping at that point.
> Added Jim to CC...
Thanks Nick. I just wanted to confirm that this latest version of the
patch works for me as well.
-Jim
next prev parent reply other threads:[~2008-11-19 19:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-19 4:53 [patch] mm: vmalloc fix lazy unmapping cache aliasing Nick Piggin
2008-11-19 4:54 ` Nick Piggin
2008-11-19 18:58 ` Jim Radford [this message]
2008-11-19 20:17 ` Russell King
2008-11-20 2:17 ` Nick Piggin
2008-11-20 18:43 ` Catalin Marinas
2008-11-20 18:43 ` Catalin Marinas
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