Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1945988AbWJZXVJ (ORCPT ); Thu, 26 Oct 2006 19:21:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1945989AbWJZXVI (ORCPT ); Thu, 26 Oct 2006 19:21:08 -0400 Received: from host-233-54.several.ru ([213.234.233.54]:60805 "EHLO mail.screens.ru") by vger.kernel.org with ESMTP id S1945984AbWJZXVE (ORCPT ); Thu, 26 Oct 2006 19:21:04 -0400 Date: Fri, 27 Oct 2006 03:20:52 +0400 From: Oleg Nesterov To: Andrew Morton Cc: Shailabh Nagar , Balbir Singh , Jay Lan , linux-kernel@vger.kernel.org Subject: [PATCH 1/6] fill_tgid: fix task_struct leak and possible oops Message-ID: <20061026232052.GA520@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: 1620 Lines: 49 1. fill_tgid() forgets to do put_task_struct(first). 2. release_task(first) can happen after fill_tgid() drops tasklist_lock, it is unsafe to dereference first->signal. This is a temporary fix, imho the locking should be reworked. Signed-off-by: Oleg Nesterov --- STATS/kernel/taskstats.c~1_fix_sig 2006-10-22 18:24:03.000000000 +0400 +++ STATS/kernel/taskstats.c 2006-10-26 23:44:32.000000000 +0400 @@ -237,14 +237,17 @@ static int fill_tgid(pid_t tgid, struct } else get_task_struct(first); - /* Start with stats from dead tasks */ - spin_lock_irqsave(&first->signal->stats_lock, flags); - if (first->signal->stats) - memcpy(stats, first->signal->stats, sizeof(*stats)); - spin_unlock_irqrestore(&first->signal->stats_lock, flags); tsk = first; read_lock(&tasklist_lock); + /* Start with stats from dead tasks */ + if (first->signal) { + spin_lock_irqsave(&first->signal->stats_lock, flags); + if (first->signal->stats) + memcpy(stats, first->signal->stats, sizeof(*stats)); + spin_unlock_irqrestore(&first->signal->stats_lock, flags); + } + do { if (tsk->exit_state == EXIT_ZOMBIE && thread_group_leader(tsk)) continue; @@ -264,7 +267,7 @@ static int fill_tgid(pid_t tgid, struct * Accounting subsytems can also add calls here to modify * fields of taskstats. */ - + put_task_struct(first); return 0; } - 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/