linux-kernel - Re: [PATCH] Allow memory hotplug and hibernation in the same kernel

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]

Date:	Sat, 14 Nov 2009 01:08:49 +0100
From:	Andi Kleen <andi@...stfloor.org>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Andi Kleen <andi@...stfloor.org>, linux-mm@...ck.org,
	gerald.schaefer@...ibm.com, rjw@...k.pl,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Allow memory hotplug and hibernation in the same kernel

On Fri, Nov 13, 2009 at 03:51:02PM -0800, Andrew Morton wrote:
> > ...
> >
> > +extern struct mutex pm_mutex;
> 
> Am a bit worried by the new mutex.

It's not a new mutex, just the existing one already used by suspend.
I only extended it's coverage to two more code paths.

> 
> > -extern struct mutex pm_mutex;
> > +static inline void lock_hibernation(void) {}
> > +static inline void unlock_hibernation(void) {}
> > +
> > +#else
> > +
> > +/* Let some subsystems like memory hotadd exclude hibernation */
> > +
> > +static inline void lock_hibernation(void)
> > +{
> > +	mutex_lock(&pm_mutex);
> > +}
> > +
> > +static inline void unlock_hibernation(void)
> > +{
> > +	mutex_unlock(&pm_mutex);
> > +}
> > +#endif
> 
> Has this been carefully reviewed and lockdep-tested to ensure that we
> didn't introduce any ab/ba nasties?

It's a "outer" global mutex for both, so I don't expect ABBA issues.

I tested hotadd/hotremove with lockdep and nothing showed up.

-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only.
--
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/