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,
lpieralisi@kernel.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, mingo@redhat.com, mgorman@suse.de,
longman@redhat.com, frederic@kernel.org,
linux-trace-kernel@vger.kernel.org, paulmck@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 v2 3/9] tracing: Warn about !rcu_is_watching()
Date: Thu, 26 Jan 2023 16:08:32 +0100 [thread overview]
Message-ID: <20230126151323.466670589@infradead.org> (raw)
In-Reply-To: 20230126150829.087606759@infradead.org
When using noinstr, WARN when tracing hits when RCU is disabled.
Suggested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
include/linux/trace_recursion.h | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
--- a/include/linux/trace_recursion.h
+++ b/include/linux/trace_recursion.h
@@ -135,6 +135,21 @@ extern void ftrace_record_recursion(unsi
# define do_ftrace_record_recursion(ip, pip) do { } while (0)
#endif
+#ifdef CONFIG_ARCH_WANTS_NO_INSTR
+# define trace_warn_on_no_rcu(ip) \
+ ({ \
+ bool __ret = !rcu_is_watching(); \
+ if (__ret && !trace_recursion_test(TRACE_RECORD_RECURSION_BIT)) { \
+ trace_recursion_set(TRACE_RECORD_RECURSION_BIT); \
+ WARN_ONCE(true, "RCU not on for: %pS\n", (void *)ip); \
+ trace_recursion_clear(TRACE_RECORD_RECURSION_BIT); \
+ } \
+ __ret; \
+ })
+#else
+# define trace_warn_on_no_rcu(ip) false
+#endif
+
/*
* Preemption is promised to be disabled when return bit >= 0.
*/
@@ -144,6 +159,9 @@ static __always_inline int trace_test_an
unsigned int val = READ_ONCE(current->trace_recursion);
int bit;
+ if (trace_warn_on_no_rcu(ip))
+ return -1;
+
bit = trace_get_context_bit() + start;
if (unlikely(val & (1 << bit))) {
/*
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next prev parent reply other threads:[~2023-01-26 15:15 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-26 15:08 [PATCH v2 0/9] A few more cpuidle vs rcu fixes Peter Zijlstra
2023-01-26 15:08 ` [PATCH v2 1/9] drivers: firmware: psci: Dont instrument suspend code Peter Zijlstra
2023-01-26 15:08 ` [PATCH v2 2/9] bug: Disable rcu_is_watching() during WARN/BUG Peter Zijlstra
2023-01-26 15:08 ` Peter Zijlstra [this message]
2023-01-26 15:08 ` [PATCH v2 4/9] tracing, preempt: Squash _rcuidle tracing Peter Zijlstra
2023-01-31 8:50 ` [PATCH v2.1 " Peter Zijlstra
2023-01-26 15:08 ` [PATCH v2 5/9] x86: Always inline arch_atomic64 Peter Zijlstra
2023-01-26 15:08 ` [PATCH v2 6/9] x86/pvclock: improve atomic update of last_value in pvclock_clocksource_read Peter Zijlstra
2023-01-26 15:08 ` [PATCH v2 7/9] x86: Mark sched_clock() noinstr Peter Zijlstra
2023-01-26 15:08 ` [PATCH v2 8/9] sched/clock: Make local_clock() noinstr Peter Zijlstra
2023-01-26 15:08 ` [PATCH v2 9/9] cpuidle: Fix poll_idle() noinstr annotation Peter Zijlstra
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