From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: [PATCH v2 7/9] tracing: Employ trace_rcu_{enter,exit}() Date: Wed, 12 Feb 2020 22:01:46 +0100 Message-ID: <20200212210750.199269033@infradead.org> References: <20200212210139.382424693@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, rostedt@goodmis.org Cc: peterz@infradead.org, 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 List-Id: linux-arch.vger.kernel.org Replace the opencoded (and incomplete) RCU manipulations with the new helpers to ensure a regular RCU context when calling into __ftrace_trace_stack(). Signed-off-by: Peter Zijlstra (Intel) --- kernel/trace/trace.c | 19 +++---------------- 1 file changed, 3 insertions(+), 16 deletions(-) --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2989,24 +2989,11 @@ void __trace_stack(struct trace_array *t int pc) { struct trace_buffer *buffer = tr->array_buffer.buffer; + unsigned long rcu_flags; - if (rcu_is_watching()) { - __ftrace_trace_stack(buffer, flags, skip, pc, NULL); - return; - } - - /* - * When an NMI triggers, RCU is enabled via rcu_nmi_enter(), - * but if the above rcu_is_watching() failed, then the NMI - * triggered someplace critical, and rcu_irq_enter() should - * not be called from NMI. - */ - if (unlikely(in_nmi())) - return; - - rcu_irq_enter_irqsave(); + rcu_flags = trace_rcu_enter(); __ftrace_trace_stack(buffer, flags, skip, pc, NULL); - rcu_irq_exit_irqsave(); + trace_rcu_exit(rcu_flags); } /** From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from merlin.infradead.org ([205.233.59.134]:33538 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729205AbgBLVOT (ORCPT ); Wed, 12 Feb 2020 16:14:19 -0500 Message-ID: <20200212210750.199269033@infradead.org> Date: Wed, 12 Feb 2020 22:01:46 +0100 From: Peter Zijlstra Subject: [PATCH v2 7/9] tracing: Employ trace_rcu_{enter,exit}() References: <20200212210139.382424693@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, rostedt@goodmis.org Cc: peterz@infradead.org, 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 Message-ID: <20200212210146.vweHi-Nf2V-NRn2cwAeZwQigLcUTv6-eVtkYCq6udtk@z> Replace the opencoded (and incomplete) RCU manipulations with the new helpers to ensure a regular RCU context when calling into __ftrace_trace_stack(). Signed-off-by: Peter Zijlstra (Intel) --- kernel/trace/trace.c | 19 +++---------------- 1 file changed, 3 insertions(+), 16 deletions(-) --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2989,24 +2989,11 @@ void __trace_stack(struct trace_array *t int pc) { struct trace_buffer *buffer = tr->array_buffer.buffer; + unsigned long rcu_flags; - if (rcu_is_watching()) { - __ftrace_trace_stack(buffer, flags, skip, pc, NULL); - return; - } - - /* - * When an NMI triggers, RCU is enabled via rcu_nmi_enter(), - * but if the above rcu_is_watching() failed, then the NMI - * triggered someplace critical, and rcu_irq_enter() should - * not be called from NMI. - */ - if (unlikely(in_nmi())) - return; - - rcu_irq_enter_irqsave(); + rcu_flags = trace_rcu_enter(); __ftrace_trace_stack(buffer, flags, skip, pc, NULL); - rcu_irq_exit_irqsave(); + trace_rcu_exit(rcu_flags); } /**