rcutorture: Make rcutorture_one_extend_check() account for hard IRQs

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@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202505140917.8ee62cc6-lkp@intel.com
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.upadhyay@kernel.org>

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index a209d2419cfdb7cbe34edff62efc5a259a5d5f55..7944cc69321dfd8e5ae1f462013e4e62e4911c5f 100644 (file)
--- 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 &&