linux-kernel - Re: [PATCH] netfilter: per-cpu spin-lock with recursion (v0.8)

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

Message-ID: <49E86539.9070408@trash.net>
Date:	Fri, 17 Apr 2009 13:17:13 +0200
From:	Patrick McHardy <kaber@...sh.net>
To:	Eric Dumazet <dada1@...mosbay.com>
CC:	Stephen Hemminger <shemminger@...tta.com>,
	paulmck@...ux.vnet.ibm.com, David Miller <davem@...emloft.net>,
	torvalds@...ux-foundation.org, jeff.chua.linux@...il.com,
	paulus@...ba.org, mingo@...e.hu, laijs@...fujitsu.com,
	jengelh@...ozas.de, r000n@...0n.net, linux-kernel@...r.kernel.org,
	netfilter-devel@...r.kernel.org, netdev@...r.kernel.org,
	benh@...nel.crashing.org
Subject: Re: [PATCH] netfilter: per-cpu spin-lock with recursion (v0.8)

Eric Dumazet wrote:
> Stephen Hemminger a écrit :
>> This version of x_tables (ip/ip6/arp) locking uses a per-cpu
>> recursive lock that can be nested. It is sort of like existing kernel_lock,
>> rwlock_t and even old 2.4 brlock.
>>
>> ...
> I like this version 8 of the patch, as it mixes all ideas we had,
> but have two questions.
> 
> Previous netfilter code (and 2.6.30-rc2 one too) disable BH, not only preemption.
> 
> I see xt_table_info_lock_all(void) does block BH, so this one is safe.
> 
> I let Patrick or other tell us if its safe to run ipt_do_table()
> with preemption disabled but BH enabled, I really dont know.

No, on jumps the return position is stored in the per-cpu copy
of the ruleset and we must prevent BH context corrupting the
value of something running in process context.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/