Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753907Ab1COWg5 (ORCPT ); Tue, 15 Mar 2011 18:36:57 -0400 Received: from mail-iw0-f174.google.com ([209.85.214.174]:42270 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752597Ab1COWg4 convert rfc822-to-8bit (ORCPT ); Tue, 15 Mar 2011 18:36:56 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=gO7yiV5/FOBbPhEgVWBM6xEaJ8wSXfOFxx/x+f4TczWa+HklZrsNTBjegiE0Bf3FaX QdHaVe+TfSPhAbOJQwRI0pD+frlEId2cXtMnkiEaMSx7VsHkSR9uSDjaNquet0kGecbl yr4GgAy9hrrOR25B93aFs7gV5BO5VvmPRtfiE= MIME-Version: 1.0 In-Reply-To: <20110315184629.GB3620@n2100.arm.linux.org.uk> References: <20110315181941.26948.65323.stgit@e102109-lin.cambridge.arm.com> <20110315184629.GB3620@n2100.arm.linux.org.uk> Date: Tue, 15 Mar 2011 22:36:55 +0000 X-Google-Sender-Auth: vQP3fmO17QiJ_-Nhh9RP63-9g-A Message-ID: Subject: Re: [PATCH] Avoid indefinite wait in smp_call_function_many() if cpumask is modified From: Catalin Marinas To: Russell King - ARM Linux Cc: Catalin Marinas , "linux-kernel@vger.kernel.org" , Andrew Morton , Saeed Bishara , Jens Axboe Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1117 Lines: 26 On Tuesday, 15 March 2011, Russell King - ARM Linux wrote: > 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. It's not that bad since the mask is copied inside the function. Anyway, it looks like such patch has been around for more than a month, so I'm not pushing it anymore. Catalin -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/