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  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:	Mon, 19 Dec 2011 05:03:45 +0100
From:	Marek Vasut <marek.vasut@...il.com>
To:	Shawn Guo <shawn.guo@...escale.com>
Cc:	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	Wolfgang Denk <wd@...x.de>, Stefano Babic <sbabic@...x.de>,
	Shawn Guo <shawn.guo@...aro.org>,
	Huang Shijie <b32955@...escale.com>,
	Sascha Hauer <s.hauer@...gutronix.de>
Subject: Re: [PATCH] MXS: Convert mutexes in clock.c to spinlocks

> On Sun, Dec 18, 2011 at 03:06:13PM +0100, Marek Vasut wrote:
> > The mutexes can't be safely used under certain circumstances. I noticed
> > this
> 
> > issue during some network instability at home:
> Yes, this is a known issue.  And there was some discussion[1] about
> why mutex is needed.

Thanks for pointing this out, I was unaware of it.

> But I really have not thought about why we can
> not use spinlock only, since using mutex only leads to the issue we
> are seeing here, and using spinlock in enable/disable and mutex in
> rate/parent will not work, because the mxs clocks have enable/disable
> and rate/parent functions access the same register.  I know it's not
> good to hold spinlock in rate/parent functions for a long time, but
> do we have a way around rather than using spinlock for both sets of
> functions?

Yea, spinlock is not good either. On the other hand, is it really held for so 
long ?

M
--
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