lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Fri, 05 Oct 2012 14:51:49 +0200 From: Maxime Bizon <mbizon@...ebox.fr> To: Eric Dumazet <eric.dumazet@...il.com> Cc: David Madore <david+ml@...ore.org>, Francois Romieu <romieu@...zoreil.com>, netdev@...r.kernel.org, linux-kernel@...r.kernel.org, Hugh Dickins <hughd@...gle.com> Subject: Re: kernel 3.2.27 on arm: WARNING: at mm/page_alloc.c:2109 __alloc_pages_nodemask+0x1d4/0x68c() On Fri, 2012-10-05 at 14:22 +0200, Eric Dumazet wrote: > Yes, but the idea of the patch was to _avoid_ next pskb_expand_head() > calls... yes but we cannot be sure of that, the caller may not have a good idea of the headroom needed for the whole lifetime of the skb it's better to think we will reduce number of calls, not avoid them that's why I think doubling the size each time is dangerous, since we silently request bigger and bigger allocations if an skb takes an unoptimized path > Hmm, > > this changes nothing assuming current_end == skb_end_offset(skb) > and current_head = skb->head My idea was to leave skb->end at its last position even if we grow skb->head. Since we have a way to know the current allocation size of skb->head, further pskb_expand_head() calls to request tailroom would just push skb->tail & skb->end together if that fits in current ksize(). I've not looked at recent changes in mainline, since you changed how skb->head is managed, that may be totally impossible. Your proposed changed API change to expand_head will fill this anyway. > New convention would be : pass number of needed bytes after current > tail, not after current end. Fully agree on this -- Maxime -- 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
Powered by blists - more mailing lists