linux-kernel - Re: [PATCH] Avoid indefinite wait in smp_call_function

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: <20110315184629.GB3620@n2100.arm.linux.org.uk>
Date:	Tue, 15 Mar 2011 18:46:29 +0000
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Catalin Marinas <catalin.marinas@....com>
Cc:	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Saeed Bishara <saeed.bishara@...il.com>,
	Jens Axboe <jens.axboe@...cle.com>
Subject: Re: [PATCH] Avoid indefinite wait in smp_call_function_many() if
	cpumask is modified

On Tue, Mar 15, 2011 at 06:20:56PM +0000, Catalin Marinas wrote:
> On ARM processors (and not only) with software broadcasting of the TLB
> maintenance operations, smp_call_function_many() is given a
> mm_cpumask(mm) as argument. This cpumask may be modified (bits cleared)
> during the smp_call_function_many() execution as a result of other
> events like ASID roll-over.

We shouldn't be modifying a mask which has been passed into one of these
functions.  Having masks change beneath a function which is actively
using it and can wait is an obvious recipe for problems and races.
--
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/