Re: [syzbot] [kernel?] possible deadlock in console_flush_all (2)

[Tetsuo Handa]

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 001fe047bd5d..237bcab72004 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -48,6 +48,7 @@
 #include <linux/mutex_api.h>
 #include <linux/plist.h>
 #include <linux/poll.h>
+#include <linux/printk.h>
 #include <linux/proc_fs.h>
 #include <linux/profile.h>
 #include <linux/psi.h>
@@ -1680,6 +1681,7 @@ static inline void
 rq_lock_irqsave(struct rq *rq, struct rq_flags *rf)
 	__acquires(rq->lock)
 {
+	printk_deferred_enter();
 	raw_spin_rq_lock_irqsave(rq, rf->flags);
 	rq_pin_lock(rq, rf);
 }
@@ -1688,6 +1690,7 @@ static inline void
 rq_lock_irq(struct rq *rq, struct rq_flags *rf)
 	__acquires(rq->lock)
 {
+	printk_deferred_enter();
 	raw_spin_rq_lock_irq(rq);
 	rq_pin_lock(rq, rf);
 }
@@ -1696,6 +1699,7 @@ static inline void
 rq_lock(struct rq *rq, struct rq_flags *rf)
 	__acquires(rq->lock)
 {
+	printk_deferred_enter();
 	raw_spin_rq_lock(rq);
 	rq_pin_lock(rq, rf);
 }
@@ -1706,6 +1710,7 @@ rq_unlock_irqrestore(struct rq *rq, struct rq_flags *rf)
 {
 	rq_unpin_lock(rq, rf);
 	raw_spin_rq_unlock_irqrestore(rq, rf->flags);
+	printk_deferred_exit();
 }
 
 static inline void
@@ -1714,6 +1719,7 @@ rq_unlock_irq(struct rq *rq, struct rq_flags *rf)
 {
 	rq_unpin_lock(rq, rf);
 	raw_spin_rq_unlock_irq(rq);
+	printk_deferred_exit();
 }
 
 static inline void
@@ -1722,6 +1728,7 @@ rq_unlock(struct rq *rq, struct rq_flags *rf)
 {
 	rq_unpin_lock(rq, rf);
 	raw_spin_rq_unlock(rq);
+	printk_deferred_exit();
 }
 
 DEFINE_LOCK_GUARD_1(rq_lock, struct rq,