netdev - Re: [PATCH] netpoll: use non-BH variant of RCU

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: <20100813143904.GA27261@gondor.apana.org.au>
Date:	Fri, 13 Aug 2010 10:39:04 -0400
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Cc:	David Miller <davem@...emloft.net>, linville@...driver.com,
	netdev@...r.kernel.org
Subject: Re: [PATCH] netpoll: use non-BH variant of RCU

On Thu, Aug 12, 2010 at 08:42:13AM -0700, Paul E. McKenney wrote:
>
> +/**
> + * rcu_read_lock_bh_irqsoff() - mark the beginning of an RCU-bh critical section
> + *
> + * This is equivalent of rcu_read_lock_bh(), but to be used where the
> + * caller either is in an irq handler or has irqs disabled.  Note that
> + * this function assumes that PREEMPT_RT kernels run irq handlers at
> + * higher priority than softirq handlers!
> + */
> +static inline void rcu_read_lock_bh_irqsoff(void)
> +{
> +	rcu_read_unlock_bh_irqsoff_check();
> +	__acquire(RCU_BH);
> +	rcu_read_acquire_bh();
> +}

Thanks for the patch Paul!

But this doesn't really solve the problem for netif_rx.  The reason
is that netif_rx can either be called with IRQs on OR off.  So we
need to take the right precautions in the case where IRQs are
enabled along with BH.

Cheers,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
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