From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH 0/8] tracing vs rcu vs nmi Date: Wed, 12 Feb 2020 11:01:06 +0100 Message-ID: <20200212100106.GA14914@hirez.programming.kicks-ass.net> References: <20200212093210.468391728@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from merlin.infradead.org ([205.233.59.134]:33092 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728745AbgBLKB3 (ORCPT ); Wed, 12 Feb 2020 05:01:29 -0500 Content-Disposition: inline In-Reply-To: <20200212093210.468391728@infradead.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, rostedt@goodmis.org, james.morse@arm.com, will@kernel.org, catalin.marinas@arm.com Cc: mingo@kernel.org, joel@joelfernandes.org, gregkh@linuxfoundation.org, gustavo@embeddedor.com, tglx@linutronix.de, paulmck@kernel.org, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com On Wed, Feb 12, 2020 at 10:32:10AM +0100, Peter Zijlstra wrote: > Hi all, > > These here patches are the result of Mathieu and Steve trying to get commit > 865e63b04e9b2 ("tracing: Add back in rcu_irq_enter/exit_irqson() for rcuidle > tracepoints") reverted again. > > One of the things discovered is that tracing MUST NOT happen before nmi_enter() > or after nmi_exit(). I've only fixed x86, but quickly gone through other > architectures and there is definitely more stuff to be fixed (simply grep for > nmi_enter in your arch). For ARM64: - apei_claim_sea() - __sdei_handler() - do_serror() - debug_exception_enter() / do_debug_exception() all look dodgy.