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Date: Fri, 07 Feb 2014 16:22:56 -0800 From: ebiederm@...ssion.com (Eric W. Biederman) To: David Miller <davem@...emloft.net> Cc: eric.dumazet@...il.com, netdev@...r.kernel.org, rientjes@...gle.com, linux-kernel@...r.kernel.org Subject: Re: [PATCH] net: use __GFP_NORETRY for high order allocations David Miller <davem@...emloft.net> writes: > From: Eric Dumazet <eric.dumazet@...il.com> > Date: Thu, 06 Feb 2014 10:42:42 -0800 > >> From: Eric Dumazet <edumazet@...gle.com> >> >> sock_alloc_send_pskb() & sk_page_frag_refill() >> have a loop trying high order allocations to prepare >> skb with low number of fragments as this increases performance. >> >> Problem is that under memory pressure/fragmentation, this can >> trigger OOM while the intent was only to try the high order >> allocations, then fallback to order-0 allocations. >> >> We had various reports from unexpected regressions. >> >> According to David, setting __GFP_NORETRY should be fine, >> as the asynchronous compaction is still enabled, and this >> will prevent OOM from kicking as in : > ... >> Signed-off-by: Eric Dumazet <edumazet@...gle.com> >> Acked-by: David Rientjes <rientjes@...gle.com> > > Applied, do we want this for -stable? The first hunk goes back to 3.12 and the second hunk goes back to 3.8. I think so. The change is safe and this class of problem can cause an external attack to trigger an OOM on your box, by controlling the packet flow. Eric -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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