netdev - Re: [PATCH][PPPOL2TP]: Fix SMP oops in pppol2tp driver

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Message-ID: <47C2B266.8070604@katalix.com>
Date:	Mon, 25 Feb 2008 12:19:50 +0000
From:	James Chapman <jchapman@...alix.com>
To:	Jarek Poplawski <jarkao2@...il.com>
CC:	David Miller <davem@...emloft.net>,
	Paul Mackerras <paulus@...ba.org>, netdev@...r.kernel.org
Subject: Re: [PATCH][PPPOL2TP]: Fix SMP oops in pppol2tp driver

Jarek Poplawski wrote:
> Jarek Poplawski wrote, On 02/21/2008 01:08 PM:
> ...
> 
>> Another, probably simpler way would be to move almost all pppol2tp_xmit
> ...
> 
> Actually, the simplest off all seems to be now this old idea to maybe make
> sk_dst_lock globally softirq immune. At least I think it's worth of testing,
> to check for these other possible lockdep warnings. It should only need to
> change all write_ and read_lock(&sk->sk_dst_lock) in very few places:
> include/net/sock.h, include/net/ip6_route.h, and net/ipv6/ipv6_sockglue.c.
> This could be tested together with you full _bh locking patch (maybe except
> these other changes in pppol2tp_xmit).

I did this and all lockdep errors have now gone. Tests ran all weekend. 
See attached patch.

Is this an acceptable solution? If so, I'll prepare and send official 
patches.


-- 
James Chapman
Katalix Systems Ltd
http://www.katalix.com
Catalysts for your Embedded Linux software development


View attachment "sk_dst_lock-softirq-safe.patch" of type "text/x-diff" (2649 bytes)