linux-kernel - Re: [patch 0/2] Run interrupt handlers always with interrupts disabled

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: <20100326092023.GH27394@elte.hu>
Date:	Fri, 26 Mar 2010 10:20:23 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Thomas Gleixner <tglx@...utronix.de>,
	Nicolas Pitre <nico@...xnic.net>,
	Linus Torvalds <torvalds@...l.org>,
	LKML <linux-kernel@...r.kernel.org>, linux-arch@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	Andi Kleen <andi@...stfloor.org>,
	David Miller <davem@...emloft.net>,
	Greg Kroah-Hartman <gregkh@...e.de>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Russell King <rmk@....linux.org.uk>
Subject: Re: [patch 0/2] Run interrupt handlers always with interrupts
 disabled


* Russell King <rmk@....linux.org.uk> wrote:

> On Fri, Mar 26, 2010 at 12:06:44AM -0000, Thomas Gleixner wrote:
> > The following patch series removes the IRQF_DISABLED functionality
> > from the core interrupt code and runs all interrupt handlers with
> > interrupts disabled.
> 
> As was covered in previous discussions, what about drivers such as SMC91x 
> which take a long time to retrieve packets from the hardware? Always running 
> handlers with IRQs disabled will kill things such as serial on these 
> platforms.

As long as it's rare (which it is) i dont see a problem: you can enable 
interrupts in the handler by using local_irq_enable(), like the IDE PIO 
drivers do. That way it's documented a bit better as well, because it shows 
the precise source of the latency, with a big comment explaining it, etc.

Thanks,

	Ingo
--
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/