From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:3201:214:fdff:fe10:1be6]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 40MGZR1S74zDr5X for ; Thu, 12 Apr 2018 19:58:35 +1000 (AEST) Date: Thu, 12 Apr 2018 10:58:11 +0100 From: Russell King - ARM Linux To: "Dmitry V. Levin" Cc: "Eric W. Biederman" , linux-sparc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Linus Torvalds , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: sparc/ppc/arm compat siginfo ABI regressions: sending SIGFPE via kill() returns wrong values in si_pid and si_uid Message-ID: <20180412095811.GC16141@n2100.armlinux.org.uk> References: <20180409152253.GD10489@altlinux.org> <20180412013435.GA21219@altlinux.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20180412013435.GA21219@altlinux.org> Sender: Russell King - ARM Linux List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Apr 12, 2018 at 04:34:35AM +0300, Dmitry V. Levin wrote: > A similar commit v4.16-rc1~159^2~37 > ("signal/arm: Document conflicts with SI_USER and SIGFPE") must have > introduced a similar ABI regression to compat arm. So, could you explain how can this change cause a regression? +#define FPE_FIXME 0 - vfp_raise_sigfpe(0, regs); + vfp_raise_sigfpe(FPE_FIXME, regs); I think you're talking garbage here - look at the damned change. It subsitutes a definition for a constant, and vfp_raise_sigfpe() ends up receiving exactly the same value bother before and after the change. The change is rather incomplete though because it should have also changed: int si_code = 0; as well. So, the commit log is accurate in this case: it _is_ about documenting the conflicting cases between SI_USER and SIGFPE and that bit of the change has no ABI effect. What does slightly annoy me is the creation of uapi/asm/siginfo.h to contain a definition that _isn't_ to be exposed as part of the UAPI. If it's not part of the UAPI, it doesn't belong in a UAPI header, period. In any case, I don't think that is exposed to userspace. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up