Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762539AbYBSC1I (ORCPT ); Mon, 18 Feb 2008 21:27:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757243AbYBSC0z (ORCPT ); Mon, 18 Feb 2008 21:26:55 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:60347 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1757033AbYBSC0y (ORCPT ); Mon, 18 Feb 2008 21:26:54 -0500 Message-ID: <47BA3E05.8020805@cn.fujitsu.com> Date: Tue, 19 Feb 2008 10:25:09 +0800 From: Shi Weihua User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 To: tony.luck@intel.com CC: linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org Subject: Re: [PATCH 4/5] signal(ia64): add a signal stack overflow check References: <47B95D4F.8030003@cn.fujitsu.com> In-Reply-To: <47B95D4F.8030003@cn.fujitsu.com> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2416 Lines: 64 The similar check has been added to x86_32(i386) in commit id 83bd01024b1fdfc41d9b758e5669e80fca72df66. So we add this check to ia64 and improve it a liitle bit in that we need to check for stack overflow only when the signal is on stack. Signed-off-by: Shi Weihua --- The previous patch has a comment mistake. Now I correct it. --- --- linux-2.6.25-rc2.orig/arch/ia64/kernel/signal.c 2008-02-16 04:57:20.000000000 +0800 +++ linux-2.6.25-rc2/arch/ia64/kernel/signal.c 2008-02-19 09:57:05.000000000 +0800 @@ -342,15 +342,33 @@ setup_frame (int sig, struct k_sigaction new_sp = scr->pt.r12; tramp_addr = (unsigned long) __kernel_sigtramp; - if ((ka->sa.sa_flags & SA_ONSTACK) && sas_ss_flags(new_sp) == 0) { - new_sp = current->sas_ss_sp + current->sas_ss_size; - /* - * We need to check for the register stack being on the signal stack - * separately, because it's switched separately (memory stack is switched - * in the kernel, register stack is switched in the signal trampoline). - */ - if (!rbs_on_sig_stack(scr->pt.ar_bspstore)) - new_rbs = (current->sas_ss_sp + sizeof(long) - 1) & ~(sizeof(long) - 1); + if (ka->sa.sa_flags & SA_ONSTACK) { + int onstack = sas_ss_flags(new_sp); + + if (onstack == 0) { + new_sp = current->sas_ss_sp + current->sas_ss_size; + /* + * We need to check for the register stack being on the + * signal stack separately, because it's switched + * separately (memory stack is switched in the kernel, + * register stack is switched in the signal trampoline). + */ + if (!rbs_on_sig_stack(scr->pt.ar_bspstore)) + new_rbs = ALIGN(current->sas_ss_sp, + sizeof(long)); + } else if (onstack == SS_ONSTACK) { + unsigned long check_sp; + + /* + * If we are on the alternate signal stack and would + * overflow it, don't. Return an always-bogus address + * instead so we will die with SIGSEGV. + */ + check_sp = (new_sp - sizeof(*frame)) & -STACK_ALIGN; + if (!likely(on_sig_stack(check_sp))) + return force_sigsegv_info(sig, (void __user *) + check_sp); + } } frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN); -- 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/