Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752924AbaJBTWI (ORCPT ); Thu, 2 Oct 2014 15:22:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58793 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751789AbaJBTWF (ORCPT ); Thu, 2 Oct 2014 15:22:05 -0400 Date: Thu, 2 Oct 2014 21:18:46 +0200 From: Oleg Nesterov To: Peter Zijlstra Cc: Peter Hurley , Fengguang Wu , Jet Chen , Su Tao , Yuanhan Liu , LKP , linux-kernel@vger.kernel.org, Marcel Holtmann Subject: Re: [rfcomm_run] WARNING: CPU: 1 PID: 79 at kernel/sched/core.c:7156 __might_sleep() Message-ID: <20141002191846.GB30606@redhat.com> References: <20140930080228.GD9561@wfg-t540p.sh.intel.com> <20141002110927.GE2849@worktop.programming.kicks-ass.net> <20141002123150.GC6324@worktop.programming.kicks-ass.net> <20141002124247.GD6324@worktop.programming.kicks-ass.net> <542D57D0.4030904@hurleysoftware.com> <20141002135250.GB10583@worktop.programming.kicks-ass.net> <20141002135805.GF6324@worktop.programming.kicks-ass.net> <542D5E3B.6000309@hurleysoftware.com> <20141002165739.GC10583@worktop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141002165739.GC10583@worktop.programming.kicks-ass.net> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ah, somehow I missed this email, I already replied to the previous one. On 10/02, Peter Zijlstra wrote: > > In any case, if we change wait_woken() like the below, then we can > simplify the loops by taking out their signal_pending checks and using > the wait_woken() return value instead. Yes, but let me repeat, > +++ b/kernel/sched/wait.c > @@ -326,8 +326,14 @@ long wait_woken(wait_queue_t *wait, unsi > * woken_wake_function() such that if we observe WQ_FLAG_WOKEN we must > * also observe all state before the wakeup. > */ > - if (!(wait->flags & WQ_FLAG_WOKEN)) > - timeout = schedule_timeout(timeout); > + if (!(wait->flags & WQ_FLAG_WOKEN)) { > + if (___wait_is_interruptible(mode)) { ___wait_is_interruptible() is pointless, signal_pending_state() does the same checks. Not to mention it will always return T in this case, note that __builtin_constant_p(state) == F. > + if (signal_pending_state(mode, current)) > + timeout = -ERESTARTSYS; OK, but unless I missed something this looks overcomplicated. You can simply do this at the start of wait_woken(). Not need to play with current->state, no need to clear WQ_FLAG_WOKEN. Oleg. -- 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/