From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.92] helo=mail.sourceforge.net) by sc8-sf-list1-new.sourceforge.net with esmtp (Exim 4.43) id 1J2YV8-0001ba-6Z for user-mode-linux-devel@lists.sourceforge.net; Wed, 12 Dec 2007 12:48:18 -0800 Received: from saraswathi.solana.com ([198.99.130.12]) by mail.sourceforge.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.44) id 1J2YV6-0006rb-IN for user-mode-linux-devel@lists.sourceforge.net; Wed, 12 Dec 2007 12:48:18 -0800 Date: Wed, 12 Dec 2007 15:47:58 -0500 From: Jeff Dike Message-ID: <20071212204758.GA9124@c2.user-mode-linux.org> Mime-Version: 1.0 Content-Disposition: inline Subject: [uml-devel] [PATCH 2/6] UML - don't kill pid 0 List-Id: The user-mode Linux development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: user-mode-linux-devel-bounces@lists.sourceforge.net Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net To: Andrew Morton Cc: LKML , uml-devel A bit of defensive programming - during development, it ocassionally happens that a call to init_new_context is missed, resulting in context holding a host pid of zero. When that address space is torn down, destroy_context does a kill(0), which instantly kills the whole UML without any errors whatsoever. This patch add a check for pids less than 2, to also catch 1 and negative pids. Signed-off-by: Jeff Dike --- arch/um/kernel/skas/mmu.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) Index: linux-2.6-git/arch/um/kernel/skas/mmu.c =================================================================== --- linux-2.6-git.orig/arch/um/kernel/skas/mmu.c 2007-12-12 15:06:14.000000000 -0500 +++ linux-2.6-git/arch/um/kernel/skas/mmu.c 2007-12-12 15:12:11.000000000 -0500 @@ -164,8 +164,20 @@ void destroy_context(struct mm_struct *m if (proc_mm) os_close_file(mmu->id.u.mm_fd); - else + else { + /* + * If init_new_context wasn't called, this will be + * zero, resulting in a kill(0), which will result in the + * whole UML suddenly dying. Also, cover negative and + * 1 cases, since they shouldn't happen either. + */ + if (mmu->id.u.pid < 2) { + printk(KERN_ERR "corrupt mm_context - pid = %d\n", + mmu->id.u.pid); + return; + } os_kill_ptraced_process(mmu->id.u.pid, 1); + } if (skas_needs_stub) free_page(mmu->id.stack); ------------------------------------------------------------------------- SF.Net email is sponsored by: Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761002AbXLLUth (ORCPT ); Wed, 12 Dec 2007 15:49:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760010AbXLLUs4 (ORCPT ); Wed, 12 Dec 2007 15:48:56 -0500 Received: from saraswathi.solana.com ([198.99.130.12]:40747 "EHLO saraswathi.solana.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759566AbXLLUsz (ORCPT ); Wed, 12 Dec 2007 15:48:55 -0500 Date: Wed, 12 Dec 2007 15:47:58 -0500 From: Jeff Dike To: Andrew Morton Cc: LKML , uml-devel Subject: [PATCH 2/6] UML - don't kill pid 0 Message-ID: <20071212204758.GA9124@c2.user-mode-linux.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A bit of defensive programming - during development, it ocassionally happens that a call to init_new_context is missed, resulting in context holding a host pid of zero. When that address space is torn down, destroy_context does a kill(0), which instantly kills the whole UML without any errors whatsoever. This patch add a check for pids less than 2, to also catch 1 and negative pids. Signed-off-by: Jeff Dike --- arch/um/kernel/skas/mmu.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) Index: linux-2.6-git/arch/um/kernel/skas/mmu.c =================================================================== --- linux-2.6-git.orig/arch/um/kernel/skas/mmu.c 2007-12-12 15:06:14.000000000 -0500 +++ linux-2.6-git/arch/um/kernel/skas/mmu.c 2007-12-12 15:12:11.000000000 -0500 @@ -164,8 +164,20 @@ void destroy_context(struct mm_struct *m if (proc_mm) os_close_file(mmu->id.u.mm_fd); - else + else { + /* + * If init_new_context wasn't called, this will be + * zero, resulting in a kill(0), which will result in the + * whole UML suddenly dying. Also, cover negative and + * 1 cases, since they shouldn't happen either. + */ + if (mmu->id.u.pid < 2) { + printk(KERN_ERR "corrupt mm_context - pid = %d\n", + mmu->id.u.pid); + return; + } os_kill_ptraced_process(mmu->id.u.pid, 1); + } if (skas_needs_stub) free_page(mmu->id.stack);