From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: [PATCH RT] sched: drop is_special_task_state() check from __set_current_state_no_track() Date: Wed, 1 Aug 2018 09:19:42 -0400 Message-ID: <20180801091942.46292953@gandalf.local.home> References: <20180801090524.7hmzfdx7r4bivekq@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: linux-rt-users@vger.kernel.org, tglx@linutronix.de, linux-kernel@vger.kernel.org, Peter Zijlstra To: Sebastian Andrzej Siewior Return-path: In-Reply-To: <20180801090524.7hmzfdx7r4bivekq@linutronix.de> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org On Wed, 1 Aug 2018 11:05:25 +0200 Sebastian Andrzej Siewior wrote: > The is_special_task_state() check in __set_current_state_no_track() > has been wrongly placed. __set_current_state_no_track() is used in RT > while a sleeping lock is acquired. It is used at the begin of the wait > loop with TASK_UNINTERRUPTIBLE and while leaving it and restoring the > original state. The latter part triggers the warning. > > Drop the special state check. This is only used within the sleeping lock > implementation and the assignment happens while the PI lock is held. > While at it, drop set_current_state_no_track() because it has no users. > > Signed-off-by: Sebastian Andrzej Siewior > --- > include/linux/sched.h | 8 -------- > 1 file changed, 8 deletions(-) > > diff --git a/include/linux/sched.h b/include/linux/sched.h > index a0c1c0cae992..b20264e17b02 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -132,16 +132,9 @@ struct task_group; > > #define __set_current_state_no_track(state_value) \ > do { \ > - WARN_ON_ONCE(is_special_task_state(state_value));\ > current->state = (state_value); \ > } while (0) I don't think we need to keep the do { } while with a single line. It is now equivalent to the non-debug version of __set_current_state() which is defined as: #define __set_current_state(state_value) \ current->state = (state_value) -- Steve > > -#define set_current_state_no_track(state_value) \ > - do { \ > - WARN_ON_ONCE(is_special_task_state(state_value));\ > - smp_store_mb(current->state, (state_value)); \ > - } while (0) > - > #define set_special_state(state_value) \ > do { \ > unsigned long flags; /* may shadow */ \ > @@ -196,7 +189,6 @@ struct task_group; > smp_store_mb(current->state, (state_value)) > > #define __set_current_state_no_track(state_value) __set_current_state(state_value) > -#define set_current_state_no_track(state_value) set_current_state(state_value) > > /* > * set_special_state() should be used for those states when the blocking task