From: David Howells <dhowells@redhat.com>
To: David Miller <davem@davemloft.net>
Cc: dhowells@redhat.com, sparclinux@vger.kernel.org,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Fix generic hugetlb pte check return type.
Date: Thu, 03 Oct 2013 09:54:17 +0100 [thread overview]
Message-ID: <20301.1380790457@warthog.procyon.org.uk> (raw)
In-Reply-To: <20131002.142509.1450460988268165850.davem@davemloft.net>
David Miller <davem@davemloft.net> wrote:
> The include/asm-generic/hugetlb.h stubs that just vector huge_pte_*()
> calls to the pte_*() implementations won't work in certain situations.
>
> x86 and sparc, for example, return "unsigned long" from the bit
> checks, and just go "return pte_val(pte) & PTE_BIT_FOO;"
>
> But since huge_pte_*() returns 'int', if any high bits on 64-bit are
> relevant, they get chopped off.
>
> The net effect is that we can loop forever trying to COW a huge page,
> because the huge_pte_write() check signals false all the time.
>
> Reported-by: Gurudas Pai <gurudas.pai@oracle.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: David Howells <dhowells@redhat.com>
prev parent reply other threads:[~2013-10-03 8:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-02 18:25 [PATCH] Fix generic hugetlb pte check return type David Miller
2013-10-02 18:25 ` David Miller
2013-10-02 22:34 ` David Rientjes
2013-10-02 22:34 ` David Rientjes
2013-10-02 23:59 ` David Miller
2013-10-03 8:54 ` David Howells [this message]
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