Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752563AbaAQQXZ (ORCPT ); Fri, 17 Jan 2014 11:23:25 -0500 Received: from mx1.redhat.com ([209.132.183.28]:47271 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751540AbaAQQXV (ORCPT ); Fri, 17 Jan 2014 11:23:21 -0500 Date: Fri, 17 Jan 2014 11:22:52 -0500 From: Kyle McMartin To: Will Deacon Cc: "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Catalin Marinas Subject: Re: [PATCH] arm64: fix strnlen_user when count <= strlen Message-ID: <20140117162252.GR18705@redacted.bos.redhat.com> References: <20140116234817.GP18705@redacted.bos.redhat.com> <20140117105107.GC16003@mudshark.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140117105107.GC16003@mudshark.cambridge.arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 17, 2014 at 10:51:07AM +0000, Will Deacon wrote: > Actually, I have removed strnlen_user for 3.14. Could you try your test case > with our for-next branch please? > > git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core > This will work fine, I believe (I can't easily test on HW since we're dependent on $vendor drivers that aren't upstream yet) but in my testing yesterday I parroted the x86 word-at-a-time.h and lib/strnlen_user.c and that seemed to work. > As for the issue you spotted, we probably need a fix for that to go into > stable kernels. Does the following (smaller patch) work for you? > This gets the count == 0 case wrong still, I believe. === count = 0 === strnlen_user = 0 __strnlen_user = 1 (Where strnlen_user is the lib/strnlen_user.c implementation.) Testing if (n <= 0) return 0; before __strnlen_user fixes it though. Given this is called in, I think, only two places in the kernel, maybe we should just backport the switch to generic for stable? I can't imagine it conflicting with anything. regards, Kyle > Will > > --->8 > > diff --git a/arch/arm64/lib/strnlen_user.S b/arch/arm64/lib/strnlen_user.S > index 7f7b176a5646..73f3335a2a45 100644 > --- a/arch/arm64/lib/strnlen_user.S > +++ b/arch/arm64/lib/strnlen_user.S > @@ -37,6 +37,7 @@ ENTRY(__strnlen_user) > USER(9f, ldrb w3, [x0], #1 ) > cbnz w3, 1b > 2: sub x0, x0, x2 > + cinc x0, x0, mi > ret > ENDPROC(__strnlen_user) > -- 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/