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:	Sat, 23 Jul 2011 11:50:30 +0200
From:	Arnd Bergmann <arnd@...db.de>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Cc:	Shawn Guo <shawn.guo@...escale.com>,
	ashishj3 <ashish.jangam@...tcummins.com>,
	Dajun <dajun.chen@...semi.com>, sameo@...nedhand.com,
	linaro-dev@...ts.linaro.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 01/11] MFD: DA9052 MFD core module v2

On Friday 22 July 2011, Mark Brown wrote:
> We went round this analysis already with the underlying I2C drivers
> (which also end up needing to take mutexes and so on) - it really does
> work out better to just make the I/O noninterruptible, the I/O is fast
> enough to not really be worth interrupting and the handling for actual
> I/O errors should normally be sufficiently different to that for user
> initiated aborts that it just adds complication.
> 
> For example, if the user interrupts while we're in the middle of some
> lengthy series of operations or wait what we really want to do is to
> tear down the high level thing we're doing in an orderly fashion.  If
> we allow the interrupt to be noticed as part of an I/O operation then
> what we often end up doing is failing that and we then have to work out
> why the I/O failed, if actually happened on a physical level and how we
> deal with that.  Usually none of these paths will be well tested.
> 
> The overall result is that the system generally becomes more complicated
> and less robust.

Yes, that makes sense. There are also cases where a mutex should really
be a spinlock (which is by definition not interruptible), or vice
versa. I don't know if this is one of them.

I agree that the safest solution here is to just make the mutex
uninterruptible.

	Arnd
--
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