From: yao zhao <dragonlinux@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Changli Gao <xiaosuo@gmail.com>,
Simon Horman <horms@verge.net.au>,
lvs-devel@vger.kernel.org, netdev@vger.kernel.org,
netfilter-devel@vger.kernel.org,
Stephen Hemminger <shemminger@vyatta.com>,
Wensong Zhang <wensong@linux-vs.org>,
Julian Anastasov <ja@ssi.bg>,
Paul E McKenney <paulmck@linux.vnet.ibm.com>
Subject: Re: [rfc] IPVS: convert scheduler management to RCU
Date: Fri, 20 Aug 2010 13:54:11 -0400 [thread overview]
Message-ID: <AANLkTin8SXBtnKsaWdb64h2UVCZ57zHFOoZUWbbz_7HM@mail.gmail.com> (raw)
In-Reply-To: <1282318337.2484.219.camel@edumazet-laptop>
On Fri, Aug 20, 2010 at 11:32 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> Le vendredi 20 août 2010 à 11:04 -0400, yao zhao a écrit :
>
>> The code here is deleting a global from the list, am I right? I didn't
>> see any called case.
>> what are you going to do more? free it? write_unlock_bh should make the mb.
>
>
> If you dont wait _after_ delete from list and following actions
> (kfree() without a call_rcu(), or module unload, or whatever), a reader
> might access your data/code and crash the box.
>
> spin_unlock_bh() wont help you at all, since only writers are freezed by
> the lock (since readers only hold rcu_lock)
>
> Documentation/RCU/whatisRCU.txt line 705
>
> Documentation/RCU/checklist.txt 15)
>
>
>
>
I read the code again and that global is in a module then you are right.
If that global is not in a module then you don't need it at all, as in
that global only functions pointer or name... which never be changed.
yao
next prev parent reply other threads:[~2010-08-20 17:54 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-20 13:33 [rfc] IPVS: convert scheduler management to RCU Simon Horman
2010-08-20 13:44 ` Changli Gao
2010-08-20 14:00 ` Simon Horman
2010-08-20 14:05 ` Eric Dumazet
2010-08-20 14:16 ` yao zhao
2010-08-20 14:32 ` Eric Dumazet
2010-08-20 15:04 ` yao zhao
2010-08-20 15:32 ` Eric Dumazet
2010-08-20 17:54 ` yao zhao [this message]
2010-08-20 14:33 ` Simon Horman
2010-08-20 14:31 ` Simon Horman
2010-08-20 13:59 ` Simon Horman
2010-08-20 19:29 ` Paul E. McKenney
2010-08-21 3:28 ` Simon Horman
2010-08-20 18:03 ` Julian Anastasov
2010-08-21 3:30 ` Simon Horman
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