Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752997AbcCGQwZ (ORCPT ); Mon, 7 Mar 2016 11:52:25 -0500 Received: from smtp43.i.mail.ru ([94.100.177.103]:54318 "EHLO smtp43.i.mail.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752418AbcCGQwS (ORCPT ); Mon, 7 Mar 2016 11:52:18 -0500 From: Stas Sergeev To: stsp@list.ru Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Andy Lutomirski , Oleg Nesterov , Shuah Khan , Ingo Molnar Subject: [PATCH v6 0/4] make sigaltstack() compatible with swapcontext() Date: Mon, 7 Mar 2016 19:52:03 +0300 Message-Id: <1457369527-11452-1-git-send-email-stsp@list.ru> X-Mailer: git-send-email 2.7.2 X-Mras: Ok Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1949 Lines: 48 The following patches make it possible to use swapcontext() in a sighandler that works on sigaltstack. The approach is inspired by Andy Lutomirski's suggestion that sigaltstack should disarm itself after saving into uc_stack: https://lkml.org/lkml/2016/2/1/594 I add the SS_AUTODISARM flag that does exactly that. On sighandler exit, the sigaltstack is restored from uc_stack. Another possible name could be SS_ONESHOT, but, since it gets always re-enabled, I choose SS_AUTODISARM. Change since v5: - Fix description of patch 4/4 Change since v4: - Implement this Andy Lutomirski's suggestion: https://lkml.org/lkml/2016/3/6/158 that allows the run-time probing of the existence of the flags added in the future. [PATCH 1/4] [Cleanup] x86: signal: unify the sigaltstack check with A clean-up patch that unifies x86's sigaltstack handling with other arches. [PATCH 2/4] sigaltstack: preparations for adding new SS_xxx flags Andy's suggested changes [PATCH 3/4] sigaltstack: implement SS_AUTODISARM flag This patch implements SS_AUTODISARM flag [PATCH 4/4] selftests: Add test for This patch adds the selftest code for new functionality CC: linux-kernel@vger.kernel.org CC: linux-api@vger.kernel.org CC: Andy Lutomirski CC: Oleg Nesterov CC: Shuah Khan CC: Ingo Molnar Diffstat: arch/x86/kernel/signal.c | 23 +-- include/linux/sched.h | 8 + include/linux/signal.h | 4 include/uapi/linux/signal.h | 7 + kernel/fork.c | 2 kernel/signal.c | 26 ++-- tools/testing/selftests/Makefile | 1 tools/testing/selftests/sigaltstack/Makefile | 8 + tools/testing/selftests/sigaltstack/sas.c | 156 +++++++++++++++++++++++++++ 9 files changed, 208 insertions(+), 27 deletions(-)