Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964857AbWJWPxl (ORCPT ); Mon, 23 Oct 2006 11:53:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964879AbWJWPxl (ORCPT ); Mon, 23 Oct 2006 11:53:41 -0400 Received: from taganka54-host.corbina.net ([213.234.233.54]:35542 "EHLO mail.screens.ru") by vger.kernel.org with ESMTP id S964857AbWJWPxk (ORCPT ); Mon, 23 Oct 2006 11:53:40 -0400 Date: Mon, 23 Oct 2006 19:53:20 +0400 From: Oleg Nesterov To: Andrew Morton Cc: Janak Desai , Peter Zijlstra , Alan Cox , linux-kernel@vger.kernel.org Subject: [PATCH] sys_unshare: remove a broken CLONE_SIGHAND code Message-ID: <20061023155320.GA4208@oleg> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2290 Lines: 67 sys_unshare(CLONE_SIGHAND) is broken, the code under 'if (new_sigh)' is never executed but very wrong. Just remove it to avoid a confusion, task_lock() has nothing to do with ->sighand changing. Also, change the comment in unshare_sighand(). Yes, CLONE_THREAD implies CLONE_SIGHAND, but still it looks confusing. Also, we don't need to check current->sighand != NULL. Signed-off-by: Oleg Nesterov --- rc2-mm2/kernel/fork.c~ 2006-10-22 19:28:17.000000000 +0400 +++ rc2-mm2/kernel/fork.c 2006-10-23 19:23:19.000000000 +0400 @@ -1523,15 +1523,13 @@ static int unshare_mnt_namespace(unsigne } /* - * Unsharing of sighand for tasks created with CLONE_SIGHAND is not - * supported yet + * Unsharing of sighand is not supported yet */ static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) { struct sighand_struct *sigh = current->sighand; - if ((unshare_flags & CLONE_SIGHAND) && - (sigh && atomic_read(&sigh->count) > 1)) + if ((unshare_flags & CLONE_SIGHAND) && atomic_read(&sigh->count) > 1) return -EINVAL; else return 0; @@ -1605,7 +1603,7 @@ asmlinkage long sys_unshare(unsigned lon int err = 0; struct fs_struct *fs, *new_fs = NULL; struct mnt_namespace *ns, *new_ns = NULL; - struct sighand_struct *sigh, *new_sigh = NULL; + struct sighand_struct *new_sigh = NULL; struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; struct files_struct *fd, *new_fd = NULL; struct sem_undo_list *new_ulist = NULL; @@ -1650,7 +1648,7 @@ asmlinkage long sys_unshare(unsigned lon } } - if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist || + if (new_fs || new_ns || new_mm || new_fd || new_ulist || new_uts || new_ipc) { task_lock(current); @@ -1672,12 +1670,6 @@ asmlinkage long sys_unshare(unsigned lon new_ns = ns; } - if (new_sigh) { - sigh = current->sighand; - rcu_assign_pointer(current->sighand, new_sigh); - new_sigh = sigh; - } - if (new_mm) { mm = current->mm; active_mm = current->active_mm; - 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/