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 for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Wed, 7 Mar 2007 06:48:16 -0800
From:	Bill Irwin <bill.irwin@...cle.com>
To:	Arjan van de Ven <arjan@...radead.org>
Cc:	Bill Irwin <bill.irwin@...cle.com>,
	Hugh Dickins <hugh@...itas.com>,
	Chuck Ebbert <cebbert@...hat.com>,
	Andi Kleen <andi@...stfloor.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: Wanted: simple, safe x86 stack overflow detection

On Tue, 2007-03-06 at 22:44 -0800, Bill Irwin wrote:
>> What do you see as the obstacle to eliminating nested IRQ's?

On Wed, Mar 07, 2007 at 04:34:52AM -0800, Arjan van de Ven wrote:
> political will, or maybe just the lack of convincing people so far

Political issues are significantly more difficult to resolve than
technical ones.


On Tue, 2007-03-06 at 22:44 -0800, Bill Irwin wrote:
>>  It doesn't
>> seem so far out to test for being on the interrupt stack and defer the
>> call to do_IRQ() until after the currently-running instance of do_IRQ()
>> has returned, or to move to per-irq stacks modulo special arrangements
>> for the per-cpu IRQ's. Or did you have other methods in mind?

On Wed, Mar 07, 2007 at 04:34:52AM -0800, Arjan van de Ven wrote:
> it's simpler...
> irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
> { 
>         irqreturn_t ret, retval = IRQ_NONE;
>         unsigned int status = 0;
> 
>         handle_dynamic_tick(action);
>    
>         if (!(action->flags & IRQF_DISABLED))
>                 local_irq_enable_in_hardirq();
> 
> just removing the if() and the explicit IRQ enabling already makes irqs no longer nest...

I can see why that would raise eyebrows. I can see getting bashed
mercilessly with interrupt latency concerns as a result here. Can you
suggest any defenses?


-- wli
-
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/

Powered by blists - more mailing lists