Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753681AbYHWGry (ORCPT ); Sat, 23 Aug 2008 02:47:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751286AbYHWGrp (ORCPT ); Sat, 23 Aug 2008 02:47:45 -0400 Received: from terminus.zytor.com ([198.137.202.10]:59070 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1749667AbYHWGro (ORCPT ); Sat, 23 Aug 2008 02:47:44 -0400 Message-ID: <48AFB1C2.5020806@zytor.com> Date: Fri, 22 Aug 2008 23:44:18 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.16 (X11/20080723) MIME-Version: 1.0 To: Jeremy Fitzhardinge CC: Andi Kleen , "H. Peter Anvin" , Dave Jones , Vegard Nossum , the arch/x86 maintainers , Linux Kernel Mailing List , Rusty Russell Subject: Re: latest -git: WARNING: at arch/x86/kernel/ipi.c:123 send_IPI_mask_bitmask+0xc3/0xe0() References: <19f34abd0808191251x4eb61c50n13ecf7c90f0f3d9f@mail.gmail.com> <20080820013930.GN9807@one.firstfloor.org> <19f34abd0808192326jc10e758m99e76bbd5714c5b8@mail.gmail.com> <20080822003659.GA7581@redhat.com> <48AE20B8.9000204@kernel.org> <20080822022841.GG23334@one.firstfloor.org> <48AE5BB8.5080701@zytor.com> <20080822093518.GK23334@one.firstfloor.org> <48AEEC4F.3060003@zytor.com> <48AFB14F.7090407@goop.org> In-Reply-To: <48AFB14F.7090407@goop.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1072 Lines: 25 Jeremy Fitzhardinge wrote: > H. Peter Anvin wrote: >> Well, smp_call_function_single already does all necessary locking; it >> makes more sense for it to check that what it's about to call still >> exists while inside the lock, instead of requiring the higher layers >> to guarantee that cannot happen on it. This is simply a matter of the >> cost of checking at this point being quite low. > > It does, already doesn't it? Hm, smp_call_function_mask() ands the > provided mask with the online mask, but it doesn't look like > smp_call_function_single() does the equivalent. It doesn't, and that's how this bug was introduced. It's a trivial add (see test patch already posted) and should hardly matter in terms of execution time. I'll write up a clean patch with all the error propagation tomorrow or Sunday. -hpa -- 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/