From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S270653AbTGNSRK (ORCPT ); Mon, 14 Jul 2003 14:17:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S270662AbTGNSRK (ORCPT ); Mon, 14 Jul 2003 14:17:10 -0400 Received: from d12lmsgate-4.de.ibm.com ([194.196.100.237]:47063 "EHLO d12lmsgate-4.de.ibm.com") by vger.kernel.org with ESMTP id S270653AbTGNSRI (ORCPT ); Mon, 14 Jul 2003 14:17:08 -0400 Importance: Normal Sensitivity: Subject: Re: sizeof (siginfo_t) problem To: jakub@redhat.com Cc: linux-kernel@vger.kernel.org X-Mailer: Lotus Notes Release 5.0.3 (Intl) 21 March 2000 Message-ID: From: "Ulrich Weigand" Date: Mon, 14 Jul 2003 20:31:34 +0200 X-MIMETrack: Serialize by Router on D12ML028/12/M/IBM(Release 5.0.9a |January 7, 2002) at 14/07/2003 20:31:39 MIME-Version: 1.0 Content-type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jakub Jelinek wrote: >I have noticed this on s390x in a different place: >MD_FALLBACK_FRAME_STATE_FOR in gcc, in order to unwind through >signal frames, needs to locate ucontext, and looking at >stack pointer + 8 + sizeof(siginfo_t) (which works on s390 32-bit) >did not work at all, everything was shifted by 8 bytes. The MD_FALLBACK_FRAME_STATE_FOR macro does not use sizeof(siginfo_t) at all, but hardcodes 128. (This has always been the case, and was done to avoid the need to include signal.h.) This is still broken with the current kernel behaviour, though. It is strange that I didn't notice the problem earlier; apparently most of the places where unwinding through signal frames is required use non-RT frames ... >This though means that the kernel siginfo_t change cannot be done >just in asm-*/siginfo.h headers - at least places where siginfo_t >is present within some structures ever visible to userland a dummy >8 byte pad needs to be inserted. As userspace expects a size of 128 bytes, and with the change the size now *is* 128 bytes, why would a pad be required? Mit freundlichen Gruessen / Best Regards Ulrich Weigand -- Dr. Ulrich Weigand Linux for S/390 Design & Development IBM Deutschland Entwicklung GmbH, Schoenaicher Str. 220, 71032 Boeblingen Phone: +49-7031/16-3727 --- Email: Ulrich.Weigand@de.ibm.com