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]
Message-ID: <1296549892_6451@mail4.comsite.net>
Date:	Tue, 01 Feb 2011 02:44:52 -0600
From:	Milton Miller <miltonm@....com>
To:	Jan Beulich <JBeulich@...ell.com>
Cc:	<linux-kernel@...r.kernel.org>
Subject: Re: calling smp_call_function_many() with non-stable CPU mask

> There are a couple of examples of smp_call_function_many() getting
> called with mm_cpumask() as the first argument. Since that mask
> generally can change while smp_call_function_many() is executing,
> it seems there might be a problem with the case where that mask
> becomes empty after the initial checks, but before the mask is made
> permanent (by copying into data->cpumask).
> 
> Shouldn't there be a check of data->refs being zero right after
> setting it (to avoid having csd_lock_wait() wait for a remote CPU
> to clear the lock flag, and to avoid adding the entry to
> call_function.queue)?
> 
> If that isn't considered necessary, is it then incorrect to pass
> in-flight CPU masks to smp_call_function_many() (and should
> this requirement then be documented somewhere, and the
> existing calls all be inspected for correctness)?
> 

Mike Galbraith just brought this up, and I supplied a patch, and even
a rediff on top of other changes:

http://lkml.indiana.edu/hypermail/linux/kernel/1101.3/02813.html
http://lkml.indiana.edu/hypermail/linux/kernel/1101.3/03172.html

http://lkml.indiana.edu/hypermail/linux/kernel/1102.0/00017.html


This doesn't address https://bugzilla.kernel.org/show_bug.cgi?id=23042 
which is x86 not expecting the mask to be cleared while its thinking
about the mask.

milton
--
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

Powered by Openwall GNU/*/Linux Powered by OpenVZ