linux-kernel - Re: [tip:x86/pat] generic-ipi: Allow cpus not yet online to call smp_call

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] [day] [month] [year] [list]

Message-Id: <1251223013.2612.11.camel@sbs-t61>
Date:	Tue, 25 Aug 2009 10:56:53 -0700
From:	Suresh Siddha <suresh.b.siddha@...el.com>
To:	Nick Piggin <npiggin@...e.de>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"mingo@...hat.com" <mingo@...hat.com>,
	"hpa@...or.com" <hpa@...or.com>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"linux-tip-commits@...r.kernel.org" 
	<linux-tip-commits@...r.kernel.org>
Subject: Re: [tip:x86/pat] generic-ipi: Allow cpus not yet online to call
 smp_call_function with irqs disabled

On Mon, 2009-08-24 at 21:29 -0700, Nick Piggin wrote:
> On Mon, Aug 24, 2009 at 01:15:43PM -0700, Suresh B wrote:
> > On Sun, 2009-08-23 at 22:40 -0700, Nick Piggin wrote:
> > > Also, I would say that we should just restrict this to wait==1 case
> > > because in that case the stack can trivially be used for data. In
> > > the wait==0 case, it is more complex. In the current implementation
> > > it should be OK (it uses per-cpu data), but we've used kmalloc
> > > there in the past, which probably wouldn't work either.
> > 
> > In future if we add any kmalloc, we already have checks in kmalloc()
> > that can be easily caught. I would like to make this change as generic
> > as possible.
> 
> Why? You think there will be much demand for it?

In the current mtrr case, we currently use wait==0

Also unless there are issues, I would like to keep it open. So that it
will encourage more usages and expose any other bugs that we perhaps
overlooked.

With all the recent generic-ipi changes, even for online cpu's, we
should be able to allow smp_call_function() with interrupts disabled for
wait==0 case, right?

thanks,
suresh

--
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/