From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161263AbWG1UIK (ORCPT ); Fri, 28 Jul 2006 16:08:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161270AbWG1UIK (ORCPT ); Fri, 28 Jul 2006 16:08:10 -0400 Received: from ra.tuxdriver.com ([70.61.120.52]:40459 "EHLO ra.tuxdriver.com") by vger.kernel.org with ESMTP id S1161267AbWG1UIE (ORCPT ); Fri, 28 Jul 2006 16:08:04 -0400 Date: Fri, 28 Jul 2006 16:07:49 -0400 From: nhorman@tuxdriver.com Message-Id: <200607282007.k6SK7nln009654@ra.tuxdriver.com> To: kernel-janitors@osdl.org, linux-kernel@vger.kernel.org, nhorman@tuxdriver.com, paulus@au.ibm.com Subject: [KJ] audit return code handling for kernel_thread [7/11] 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 drivers/macintosh/mediabay.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/macintosh/mediabay.c +++ b/drivers/macintosh/mediabay.c @@ -699,7 +699,8 @@ static int __devinit media_bay_attach(st /* Startup kernel thread */ if (i == 0) - kernel_thread(media_bay_task, NULL, CLONE_KERNEL); + if (kernel_thread(media_bay_task, NULL, CLONE_KERNEL) < 0) + printk(KERN_WARNING "Could not start media bay task\n"); return 0;