netdev - Re: softlockups when trying to restore an nft set of 1M entries

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Sat, 14 Feb 2015 04:32:10 +0000
From:	Thomas Graf <tgraf@...g.ch>
To:	Josh Hunt <johunt@...mai.com>
Cc:	Pablo Neira Ayuso <pablo@...filter.org>,
	Patrick McHardy <kaber@...sh.net>,
	netfilter-devel@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: softlockups when trying to restore an nft set of 1M entries

On 02/13/15 at 05:59am, Josh Hunt wrote:
> except inside the set definition above I add 1M random ipv4 addresses.
> Running "nft -f <filename>" will reproduce the problem. I also saw this when
> trying to do a restore of 250k entries.
> 
> There are a few problems going on from what I can tell. The first is
> the set defaults to 4 buckets and during restores the # of buckets does not
> increase. I'm currently investigating to understand why we don't expand the
> set on restores. However my guess into why we're softlockuping here is that
> we're trying to shove 1M entries into 4 buckets :)

Agreed. If you grow from 4 to cover 1M entries you need countless
growth cycles and you end up creating huge chains which will make the
ongoing expands take even longer.

I think we need to implement Herbert's suggestion and have inserts
fail if a certain upper watermark is reached.

I'm also investigating if we can grow by n*2 instead of just *2.
--
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