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 Content-Length: 1664 Lines: 45 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); -- 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/