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From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org
Cc: will@kernel.org, peterz@infradead.org, boqun.feng@gmail.com,
	mark.rutland@arm.com, tglx@linutronix.de, bp@alien8.de,
	dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
	seanjc@google.com, pbonzini@redhat.com, jgross@suse.com,
	srivatsa@csail.mit.edu, amakhalov@vmware.com,
	pv-drivers@vmware.com, rostedt@goodmis.org, mhiramat@kernel.org,
	wanpengli@tencent.com, vkuznets@redhat.com,
	boris.ostrovsky@oracle.com, rafael@kernel.org,
	daniel.lezcano@linaro.org, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
	vschneid@redhat.com, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
	linux-trace-kernel@vger.kernel.org, linux-pm@vger.kernel.org
Subject: [PATCH 3/6] ftrace/x86: Warn and ignore graph tracing when RCU is disabled
Date: Mon, 23 Jan 2023 21:50:12 +0100	[thread overview]
Message-ID: <20230123205515.059999893@infradead.org> (raw)
In-Reply-To: 20230123205009.790550642@infradead.org

All RCU disabled code should be noinstr and hence we should never get
here -- when we do, WARN about it and make sure to not actually do
tracing.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/kernel/ftrace.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -646,6 +646,9 @@ void prepare_ftrace_return(unsigned long
 	if (unlikely(atomic_read(&current->tracing_graph_pause)))
 		return;
 
+	if (WARN_ONCE(!rcu_is_watching(), "RCU not on for: %pS\n", (void *)ip))
+		return;
+
 	bit = ftrace_test_recursion_trylock(ip, *parent);
 	if (bit < 0)
 		return;



WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org
Cc: mark.rutland@arm.com, juri.lelli@redhat.com,
	daniel.lezcano@linaro.org, wanpengli@tencent.com,
	kvm@vger.kernel.org, rafael@kernel.org, peterz@infradead.org,
	dave.hansen@linux.intel.com,
	virtualization@lists.linux-foundation.org, bsegall@google.com,
	amakhalov@vmware.com, will@kernel.org, tglx@linutronix.de,
	vschneid@redhat.com, hpa@zytor.com, x86@kernel.org,
	pv-drivers@vmware.com, mgorman@suse.de,
	linux-trace-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	boqun.feng@gmail.com, rostedt@goodmis.org, bp@alien8.de,
	vincent.guittot@linaro.org, boris.ostrovsky@oracle.com,
	dietmar.eggemann@arm.com, jgross@suse.com, seanjc@google.com,
	linux-kernel@vger.kernel.org, mhiramat@kernel.org,
	pbonzini@redhat.com, bristot@redhat.com
Subject: [PATCH 3/6] ftrace/x86: Warn and ignore graph tracing when RCU is disabled
Date: Mon, 23 Jan 2023 21:50:12 +0100	[thread overview]
Message-ID: <20230123205515.059999893@infradead.org> (raw)
In-Reply-To: 20230123205009.790550642@infradead.org

All RCU disabled code should be noinstr and hence we should never get
here -- when we do, WARN about it and make sure to not actually do
tracing.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/kernel/ftrace.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -646,6 +646,9 @@ void prepare_ftrace_return(unsigned long
 	if (unlikely(atomic_read(&current->tracing_graph_pause)))
 		return;
 
+	if (WARN_ONCE(!rcu_is_watching(), "RCU not on for: %pS\n", (void *)ip))
+		return;
+
 	bit = ftrace_test_recursion_trylock(ip, *parent);
 	if (bit < 0)
 		return;


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Virtualization@lists.linux-foundation.org
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  parent reply	other threads:[~2023-01-23 20:58 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-23 20:50 [PATCH 0/6] A few cpuidle vs rcu fixes Peter Zijlstra
2023-01-23 20:50 ` Peter Zijlstra
2023-01-23 20:50 ` [PATCH 1/6] x86: Always inline arch_atomic64 Peter Zijlstra
2023-01-23 20:50   ` Peter Zijlstra
2023-01-23 20:50 ` [PATCH 2/6] x86/pvclock: improve atomic update of last_value in pvclock_clocksource_read Peter Zijlstra
2023-01-23 20:50   ` Peter Zijlstra
2023-01-23 20:50 ` Peter Zijlstra [this message]
2023-01-23 20:50   ` [PATCH 3/6] ftrace/x86: Warn and ignore graph tracing when RCU is disabled Peter Zijlstra
2023-01-23 21:53   ` Steven Rostedt
2023-01-23 21:53     ` Steven Rostedt
2023-01-23 22:07     ` Steven Rostedt
2023-01-23 22:07       ` Steven Rostedt
2023-01-24 14:44       ` Peter Zijlstra
2023-01-24 14:44         ` Peter Zijlstra
2023-01-24 17:12         ` Mark Rutland
2023-01-24 17:12           ` Mark Rutland
2023-01-25  9:37           ` Peter Zijlstra
2023-01-25  9:37             ` Peter Zijlstra
2023-01-25 10:47           ` Peter Zijlstra
2023-01-25 10:47             ` Peter Zijlstra
2023-01-25 11:32             ` Mark Rutland
2023-01-25 11:32               ` Mark Rutland
2023-01-25 18:46             ` Paul E. McKenney
2023-01-26  9:28               ` Peter Zijlstra
2023-01-26  9:28                 ` Peter Zijlstra
2023-01-28 19:12                 ` Paul E. McKenney
2023-01-23 20:50 ` [PATCH 4/6] x86: Mark sched_clock() noinstr Peter Zijlstra
2023-01-23 20:50   ` Peter Zijlstra
2023-01-23 20:50 ` [PATCH 5/6] sched/clock: Make local_clock() noinstr Peter Zijlstra
2023-01-23 20:50   ` Peter Zijlstra
2023-01-23 20:50 ` [PATCH 6/6] cpuidle: Fix poll_idle() noinstr annotation Peter Zijlstra
2023-01-23 20:50   ` Peter Zijlstra
2023-01-24 14:24   ` Rafael J. Wysocki
2023-01-24 14:24     ` Rafael J. Wysocki
2023-01-24 16:34 ` [PATCH 0/6] A few cpuidle vs rcu fixes Mark Rutland
2023-01-24 16:34   ` Mark Rutland
2023-01-24 17:30   ` Mark Rutland
2023-01-24 17:30     ` Mark Rutland
2023-01-24 18:39     ` Mark Rutland
2023-01-24 18:39       ` Mark Rutland
2023-01-25  9:35       ` Peter Zijlstra
2023-01-25  9:35         ` Peter Zijlstra
2023-01-25  9:40         ` Peter Zijlstra
2023-01-25  9:40           ` Peter Zijlstra
2023-01-25 10:23           ` Mark Rutland
2023-01-25 10:23             ` Mark Rutland
2023-01-31 14:22           ` [tip: sched/core] cpuidle: tracing, preempt: Squash _rcuidle tracing tip-bot2 for Peter Zijlstra
2023-01-25  9:31   ` [PATCH 0/6] A few cpuidle vs rcu fixes Peter Zijlstra
2023-01-25  9:31     ` Peter Zijlstra
2023-01-25  9:36     ` Mark Rutland
2023-01-25  9:36       ` Mark Rutland
2023-01-25 15:20 ` Mark Rutland
2023-01-25 15:20   ` Mark Rutland

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