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Message-ID: <2963e725-588c-4390-9bc1-525414bb101c@I-love.SAKURA.ne.jp>
Date: Tue, 5 Mar 2024 23:05:16 +0900
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Subject: Re: [syzbot] [kernel?] possible deadlock in console_flush_all (2)
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To: syzbot <syzbot+f78380e4eae53c64125c@syzkaller.appspotmail.com>,
        linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
References: <000000000000e40a2906072e9567@google.com>
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
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#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,