linux-kernel - [PATCH rcu 03/15] rcutorture: Make rcutorture_one_extend

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Message-Id: <20250709104215.15562-4-neeraj.upadhyay@kernel.org>
Date: Wed,  9 Jul 2025 16:12:03 +0530
From: neeraj.upadhyay@...nel.org
To: rcu@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	paulmck@...nel.org,
	joelagnelf@...dia.com,
	frederic@...nel.org,
	boqun.feng@...il.com,
	urezki@...il.com,
	rostedt@...dmis.org,
	mathieu.desnoyers@...icios.com,
	jiangshanlai@...il.com,
	qiang.zhang1211@...il.com,
	neeraj.iitr10@...il.com,
	neeraj.upadhyay@....com,
	"Neeraj Upadhyay (AMD)" <neeraj.upadhyay@...nel.org>,
	kernel test robot <oliver.sang@...el.com>
Subject: [PATCH rcu 03/15] rcutorture: Make rcutorture_one_extend_check() account for hard IRQs

From: "Paul E. McKenney" <paulmck@...nel.org>

This commit retrospectively prepares for testing of RCU readers invoked
from hardware interrupt handlers (for example, HRTIMER_MODE_HARD hrtimer
handlers) in kernels built with CONFIG_RCU_TORTURE_TEST_CHK_RDR_STATE=y,
which is rarely used but sometimes extremely useful.  This preparation
involves taking early exits if in_hardirq(), and, while we are in the
area, a very early exit if in_nmi().

This means that a number of insoftirq parameters are no longer needed,
but that is the subject of a later commit.

Reported-by: kernel test robot <oliver.sang@...el.com>
Closes: https://lore.kernel.org/oe-lkp/202505140917.8ee62cc6-lkp@intel.com
Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
Tested-by: kernel test robot <oliver.sang@...el.com>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.upadhyay@...nel.org>
---
 kernel/rcu/rcutorture.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index a209d2419cfd..7944cc69321d 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1920,10 +1920,10 @@ static void rcutorture_one_extend_check(char *s, int curstate, int new, int old,
 {
 	int mask;
 
-	if (!IS_ENABLED(CONFIG_RCU_TORTURE_TEST_CHK_RDR_STATE))
+	if (!IS_ENABLED(CONFIG_RCU_TORTURE_TEST_CHK_RDR_STATE) || in_nmi())
 		return;
 
-	WARN_ONCE(!(curstate & RCUTORTURE_RDR_IRQ) && irqs_disabled(), ROEC_ARGS);
+	WARN_ONCE(!(curstate & RCUTORTURE_RDR_IRQ) && irqs_disabled() && !in_hardirq(), ROEC_ARGS);
 	WARN_ONCE((curstate & RCUTORTURE_RDR_IRQ) && !irqs_disabled(), ROEC_ARGS);
 
 	// If CONFIG_PREEMPT_COUNT=n, further checks are unreliable.
@@ -1938,9 +1938,9 @@ static void rcutorture_one_extend_check(char *s, int curstate, int new, int old,
 		  (curstate & (RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2)) &&
 		  cur_ops->readlock_nesting() == 0, ROEC_ARGS);
 
-	// Timer handlers have all sorts of stuff disabled, so ignore
+	// Interrupt handlers have all sorts of stuff disabled, so ignore
 	// unintended disabling.
-	if (insoftirq)
+	if (in_serving_softirq() || in_hardirq())
 		return;
 
 	WARN_ONCE(cur_ops->extendables &&
-- 
2.40.1