From: David Howells <dhowells@redhat.com>
To: Hannes Hering <hannes.hering@linux.vnet.ibm.com>
Cc: themann@de.ibm.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, ossrosch@linux.vnet.ibm.com,
linuxppc-dev@ozlabs.org, raisch@de.ibm.com, ossthema@de.ibm.com,
osstklei@de.ibm.com, David Miller <davem@davemloft.net>
Subject: Re: [PATCH 2.6.30-rc5] ehea: fix invalid pointer access
Date: Tue, 05 May 2009 13:19:54 +0100 [thread overview]
Message-ID: <26110.1241525994@redhat.com> (raw)
In-Reply-To: <200905051319.05806.hannes.hering@linux.vnet.ibm.com>
Hannes Hering <hannes.hering@linux.vnet.ibm.com> wrote:
> this is an ehea driver problem, which is occuring when the receive queue runs
> empty. The faulting code is more specifically the following line:
>
> pref = (skb_array[x]->data);
In that case, you might want to move the prefetchw() calls in the following:
pref = skb_array[x];
- prefetchw(pref);
- prefetchw(pref + EHEA_CACHE_LINE);
+ if (pref) {
+ prefetchw(pref);
+ prefetchw(pref + EHEA_CACHE_LINE);
to before the if-statement. That way the CPU can be attempting the prefetch
whilst it's chewing over the test and branch. prefetching shouldn't fault on
a bad address.
David
WARNING: multiple messages have this Message-ID (diff)
From: David Howells <dhowells@redhat.com>
To: Hannes Hering <hannes.hering@linux.vnet.ibm.com>
Cc: dhowells@redhat.com, David Miller <davem@davemloft.net>,
themann@de.ibm.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, raisch@de.ibm.com,
ossrosch@linux.vnet.ibm.com, linuxppc-dev@ozlabs.org,
ossthema@de.ibm.com, osstklei@de.ibm.com
Subject: Re: [PATCH 2.6.30-rc5] ehea: fix invalid pointer access
Date: Tue, 05 May 2009 13:19:54 +0100 [thread overview]
Message-ID: <26110.1241525994@redhat.com> (raw)
In-Reply-To: <200905051319.05806.hannes.hering@linux.vnet.ibm.com>
Hannes Hering <hannes.hering@linux.vnet.ibm.com> wrote:
> this is an ehea driver problem, which is occuring when the receive queue runs
> empty. The faulting code is more specifically the following line:
>
> pref = (skb_array[x]->data);
In that case, you might want to move the prefetchw() calls in the following:
pref = skb_array[x];
- prefetchw(pref);
- prefetchw(pref + EHEA_CACHE_LINE);
+ if (pref) {
+ prefetchw(pref);
+ prefetchw(pref + EHEA_CACHE_LINE);
to before the if-statement. That way the CPU can be attempting the prefetch
whilst it's chewing over the test and branch. prefetching shouldn't fault on
a bad address.
David
next prev parent reply other threads:[~2009-05-05 12:22 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-04 16:02 [PATCH 2.6.30-rc5] ehea: fix invalid pointer access Hannes Hering
2009-05-04 16:02 ` Hannes Hering
2009-05-04 18:07 ` David Miller
2009-05-04 18:07 ` David Miller
2009-05-05 9:11 ` David Howells
2009-05-05 9:11 ` David Howells
2009-05-05 11:19 ` Hannes Hering
2009-05-05 11:19 ` Hannes Hering
2009-05-05 12:19 ` David Howells [this message]
2009-05-05 12:19 ` David Howells
2009-05-05 13:45 ` Hannes Hering
2009-05-05 13:45 ` Hannes Hering
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