From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932915Ab3GVQTX (ORCPT ); Mon, 22 Jul 2013 12:19:23 -0400 Received: from mail-pb0-f48.google.com ([209.85.160.48]:36797 "EHLO mail-pb0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932848Ab3GVQMC (ORCPT ); Mon, 22 Jul 2013 12:12:02 -0400 From: Peng Tao To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, Hiroya Nozaki , Peng Tao , Andreas Dilger Subject: [PATCH 27/48] staging/lustre/ptlrpc: Race between start and stop service threads Date: Tue, 23 Jul 2013 00:06:48 +0800 Message-Id: <1374509230-3324-28-git-send-email-bergwolf@gmail.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1374509230-3324-1-git-send-email-bergwolf@gmail.com> References: <1374509230-3324-1-git-send-email-bergwolf@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hiroya Nozaki When ptlrpc_start_thread fails to create a new thread, it will finalize and free a struct ptlrpc_thread created and used here. Considering this, it can be a problem when ptlrpc_svcpt_stop_thread is driven and handles the struct ptlrpc_thread right after or right before failure of cfs_create_thread. Because this situation let the both of ptlrpc_start_thread and ptlrpc_svcpt_stop_threads access the freed ptlrpc_thread and cause OS panic. Or, it may happen that ptlrpc_svcpt_stop_threads waits forever holding an already-freed waitq. This patch adds an error handling into ptlrpc_start_thread to fix this problem. Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-2889 Lustre-change: http://review.whamcloud.com/5552 Signed-off-by: Hiroya Nozaki Reviewed-by: Liang Zhen Reviewed-by: Nikitas Angelinas Reviewed-by: Keith Mannthey Reviewed-by: Oleg Drokin Signed-off-by: Peng Tao Signed-off-by: Andreas Dilger --- drivers/staging/lustre/lustre/ptlrpc/service.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/staging/lustre/lustre/ptlrpc/service.c b/drivers/staging/lustre/lustre/ptlrpc/service.c index 6871711..87bd638 100644 --- a/drivers/staging/lustre/lustre/ptlrpc/service.c +++ b/drivers/staging/lustre/lustre/ptlrpc/service.c @@ -2765,11 +2765,19 @@ int ptlrpc_start_thread(struct ptlrpc_service_part *svcpt, int wait) CERROR("cannot start thread '%s': rc %d\n", thread->t_name, rc); spin_lock(&svcpt->scp_lock); - list_del(&thread->t_link); --svcpt->scp_nthrs_starting; - spin_unlock(&svcpt->scp_lock); - - OBD_FREE(thread, sizeof(*thread)); + if (thread_is_stopping(thread)) { + /* this ptlrpc_thread is being hanled + * by ptlrpc_svcpt_stop_threads now + */ + thread_add_flags(thread, SVC_STOPPED); + wake_up(&thread->t_ctl_waitq); + spin_unlock(&svcpt->scp_lock); + } else { + list_del(&thread->t_link); + spin_unlock(&svcpt->scp_lock); + OBD_FREE_PTR(thread); + } RETURN(rc); } -- 1.7.9.5