linux-kernel - Re: [PATCH v2 00/26] genirq: fix use of irq_find

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: <alpine.DEB.2.10.1408262333420.3323@nanos>
Date:	Tue, 26 Aug 2014 23:34:51 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Marc Zyngier <marc.zyngier@....com>
cc:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-omap@...r.kernel.org, linux@...ts.openrisc.net,
	linux@....linux.org.uk, shawn.guo@...escale.com,
	kernel@...gutronix.de, tony@...mide.com, catalin.marinas@....com,
	will.deacon@....com, jonas@...thpole.se, jason@...edaemon.net,
	shc_work@...l.ru, baohua@...nel.org,
	maxime.ripard@...e-electrons.com, khilman@...aro.org,
	sboyd@...eaurora.org, lorenzo.pieralisi@....com,
	larry.bassel@...aro.org, mark.rutland@....com,
	sudeep.holla@....com, stefan.kristiansson@...nalahti.fi,
	vkale@....com, schwidefsky@...ibm.com
Subject: Re: [PATCH v2 00/26] genirq: fix use of irq_find_mapping outside of
 legal RCU context

On Tue, 26 Aug 2014, Marc Zyngier wrote:

> A number of irqchip drivers are directly calling irq_find_mapping,
> which may use a rcu_read_lock call when walking the radix tree.
> 
> Turns out that if you hit that point with CONFIG_PROVE_RCU enabled,
> the kernel will shout at you, as using RCU in this context may be
> illegal (specially if coming from the idle state, where RCU would be
> in a quiescent state).
> 
> A possible fix would be to wrap calls to irq_find_mapping into a
> RCU_NONIDLE macro, but that really looks ugly.
> 
> This patch series introduce another generic IRQ entry point
> (handle_domain_irq), which has the exact same behaviour as handle_IRQ
> (as defined on arm, arm64 and openrisc), except that it also takes a
> irq_domain pointer. This allows the logical IRQ lookup to be done
> inside the irq_{enter,exit} section, which contains a
> rcu_irq_{enter,exit}, making it safe.

Looks good. Should this be routed to the genirq tree?

Thanks,

	tglx
--
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/