From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-2949743-1517976899-2-5223934733193571741 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.001, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='US-ASCII' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1517976899; b=KLWJl/GIa2RmNCyb2yzhJBRsp3ssXP6dOauGw7CnAJGS5vN 1SDUz60x2jCdmjY4rJpi7Qn9wQyoDA5W/Jycs5X+5wXoAWXdF5KF3i3JD3i7ovrw p3EJ5tqhi/rsUPB8ESofbD9mPrwwN/XQubvp4HCQlrgE6FzQvYnCzVivgS8PZLs8 tBWkXK+OnucJSGYAS+p+1ktiBPFdsM8T461lGarUpx3GqzW6AaVBnTiq9S/UJJBJ gleksPa48jmIZ3/7JXXTajZbhK1YVf7To2O8Jt+M2wujfj/V9Q415DnHke+I9mgK ypyG5DaImoJirckT956VvhUsEXFMYIl7dKNEDhg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:subject:message-id :in-reply-to:references:mime-version:content-type :content-transfer-encoding:sender:list-id; s=arctest; t= 1517976899; bh=cIOQFlhJ4Dmm0lA3yRuGIRuFFqTENNdxpd4KwZStdrc=; b=q T3lMz+8Uvjz2amSamCB1GABhX7WOlLqAGcoSe9+y30DV9cY9/0Rqj8PPt4ksqdN9 kSct0cgrKhToAxdiWrQYfRiBzHc6b6SYcm78SfHDM2NDERR5UvTmy1/YgfC4V0Ew 0w6yQ3h9pZ3Qk+2xJhFus3ASxLSs2907dv/T1wwThctMEx262ryVvHRRJRVVsI9K VTc0OuIaYDH3rnXBp/im6EydRj9wzG9oWeuaTPCN5yuR6jSd6IKtfFLcZeqYvJ+g 0tHRmaIy2ElH04xyZGvcExhcQcWtRYuuSl1ZjMK2a/Vgnti+L36c4XeENaNGW+4J Sg4GDmt93HWALwHCvdu6w== ARC-Authentication-Results: i=1; mx5.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=goodmis.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=goodmis.org header.result=pass header_is_org_domain=yes Authentication-Results: mx5.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=goodmis.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=goodmis.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753246AbeBGEOp (ORCPT ); Tue, 6 Feb 2018 23:14:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:45354 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752564AbeBGEOo (ORCPT ); Tue, 6 Feb 2018 23:14:44 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0E7352075D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Date: Tue, 6 Feb 2018 23:14:40 -0500 From: Steven Rostedt To: "tip-bot for Steven Rostedt (VMware)" Cc: pkondeti@codeaurora.org, hpa@zytor.com, linux-kernel@vger.kernel.org, rostedt@goodmis.org, efault@gmx.de, peterz@infradead.org, akpm@linux-foundation.org, torvalds@linux-foundation.org, mingo@kernel.org, tglx@linutronix.de, linux-tip-commits@vger.kernel.org, stable@vger.kernel.org Subject: Re: [tip:sched/urgent] sched/rt: Use container_of() to get root domain in rto_push_irq_work_func() Message-ID: <20180206231440.4bc7f636@vmware.local.home> In-Reply-To: References: X-Mailer: Claws Mail 3.15.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: I see this was just applied to Linus's tree. It probably should be tagged for stable as well. -- Steve On Tue, 6 Feb 2018 03:54:16 -0800 "tip-bot for Steven Rostedt (VMware)" wrote: > Commit-ID: ad0f1d9d65938aec72a698116cd73a980916895e > Gitweb: https://git.kernel.org/tip/ad0f1d9d65938aec72a698116cd73a980916895e > Author: Steven Rostedt (VMware) > AuthorDate: Tue, 23 Jan 2018 20:45:37 -0500 > Committer: Ingo Molnar > CommitDate: Tue, 6 Feb 2018 10:20:33 +0100 > > sched/rt: Use container_of() to get root domain in rto_push_irq_work_func() > > When the rto_push_irq_work_func() is called, it looks at the RT overloaded > bitmask in the root domain via the runqueue (rq->rd). The problem is that > during CPU up and down, nothing here stops rq->rd from changing between > taking the rq->rd->rto_lock and releasing it. That means the lock that is > released is not the same lock that was taken. > > Instead of using this_rq()->rd to get the root domain, as the irq work is > part of the root domain, we can simply get the root domain from the irq work > that is passed to the routine: > > container_of(work, struct root_domain, rto_push_work) > > This keeps the root domain consistent. > > Reported-by: Pavan Kondeti > Signed-off-by: Steven Rostedt (VMware) > Signed-off-by: Peter Zijlstra (Intel) > Cc: Andrew Morton > Cc: Linus Torvalds > Cc: Mike Galbraith > Cc: Peter Zijlstra > Cc: Thomas Gleixner > Fixes: 4bdced5c9a292 ("sched/rt: Simplify the IPI based RT balancing logic") > Link: http://lkml.kernel.org/r/CAEU1=PkiHO35Dzna8EQqNSKW1fr1y1zRQ5y66X117MG06sQtNA@mail.gmail.com > Signed-off-by: Ingo Molnar > --- > kernel/sched/rt.c | 15 ++++++++------- > 1 file changed, 8 insertions(+), 7 deletions(-) > > diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c > index 862a513..2fb627d 100644 > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -1907,9 +1907,8 @@ static void push_rt_tasks(struct rq *rq) > * the rt_loop_next will cause the iterator to perform another scan. > * > */ > -static int rto_next_cpu(struct rq *rq) > +static int rto_next_cpu(struct root_domain *rd) > { > - struct root_domain *rd = rq->rd; > int next; > int cpu; > > @@ -1985,7 +1984,7 @@ static void tell_cpu_to_push(struct rq *rq) > * Otherwise it is finishing up and an ipi needs to be sent. > */ > if (rq->rd->rto_cpu < 0) > - cpu = rto_next_cpu(rq); > + cpu = rto_next_cpu(rq->rd); > > raw_spin_unlock(&rq->rd->rto_lock); > > @@ -1998,6 +1997,8 @@ static void tell_cpu_to_push(struct rq *rq) > /* Called from hardirq context */ > void rto_push_irq_work_func(struct irq_work *work) > { > + struct root_domain *rd = > + container_of(work, struct root_domain, rto_push_work); > struct rq *rq; > int cpu; > > @@ -2013,18 +2014,18 @@ void rto_push_irq_work_func(struct irq_work *work) > raw_spin_unlock(&rq->lock); > } > > - raw_spin_lock(&rq->rd->rto_lock); > + raw_spin_lock(&rd->rto_lock); > > /* Pass the IPI to the next rt overloaded queue */ > - cpu = rto_next_cpu(rq); > + cpu = rto_next_cpu(rd); > > - raw_spin_unlock(&rq->rd->rto_lock); > + raw_spin_unlock(&rd->rto_lock); > > if (cpu < 0) > return; > > /* Try the next RT overloaded CPU */ > - irq_work_queue_on(&rq->rd->rto_push_work, cpu); > + irq_work_queue_on(&rd->rto_push_work, cpu); > } > #endif /* HAVE_RT_PUSH_IPI */ >