From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161261AbWG1UHa (ORCPT ); Fri, 28 Jul 2006 16:07:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161263AbWG1UHa (ORCPT ); Fri, 28 Jul 2006 16:07:30 -0400 Received: from ra.tuxdriver.com ([70.61.120.52]:33291 "EHLO ra.tuxdriver.com") by vger.kernel.org with ESMTP id S1161261AbWG1UH3 (ORCPT ); Fri, 28 Jul 2006 16:07:29 -0400 Date: Fri, 28 Jul 2006 16:07:13 -0400 From: nhorman@tuxdriver.com Message-Id: <200607282007.k6SK7DhX009584@ra.tuxdriver.com> To: kernel-janitors@osdl.org, linux-kernel@vger.kernel.org, nhorman@tuxdriver.com, schwidefsky@de.ibm.com Subject: [KJ] audit return code handling for kernel_thread [2/11] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Audit/Cleanup of kernel_thread calls, specifically checking of return codes. Problems seemed to fall into 3 main categories: 1) callers of kernel_thread were inconsistent about meaning of a zero return code. Some callers considered a zero return code to mean success, others took it to mean failure. a zero return code, while not actually possible in the current implementation, should be considered a success (pid 0 is/should be valid). fixed all callers to treat zero return as success 2) caller of kernel_thread saved return code of kernel_thread for later use without ever checking its value. Callers who did this tended to assume a non-zero return was success, and would often wait for a completion queue to be woken up, implying that an error (negative return code) from kernel_thread could lead to deadlock. Repaired by checking return code at call time, and setting saved return code to zero in the event of an error. 3) callers of kernel_thread never bothered to check the return code at all. This can lead to seemingly unrelated errors later in execution. Fixed by checking return code at call time and printing a warning message on failure. Regards Neil Signed-off-by: Neil Horman arch/s390/mm/cmm.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/arch/s390/mm/cmm.c +++ b/arch/s390/mm/cmm.c @@ -161,7 +161,10 @@ cmm_thread(void *dummy) static void cmm_start_thread(void) { - kernel_thread(cmm_thread, NULL, 0); + if (kernel_thread(cmm_thread, NULL, 0) < 0) { + printk(KERN_WARNING "Could not start cmm thread\n"); + clear_bit(0,&cmm_thread_active); + } } static void