rcu: Make call_rcu_tasks() tolerate first call with irqs disabled
Currently, if the very first call to call_rcu_tasks() has irqs disabled,
it will create the rcu_tasks_kthread with irqs disabled, which will
result in a splat in the memory allocator, which kthread_run() invokes
with the expectation that irqs are enabled.
This commit fixes this problem by deferring kthread creation if called
with irqs disabled. The first call to call_rcu_tasks() that has irqs
enabled will create the kthread.
This bug was detected by rcutorture changes that were motivated by
Iftekhar Ahmed's mutation-testing efforts.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index a8af797..3bc5de0 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -45,6 +45,7 @@
#include <linux/bug.h>
#include <linux/compiler.h>
#include <linux/ktime.h>
+#include <linux/irqflags.h>
#include <asm/barrier.h>