From 809631e2bff5aba056df75cc4e43127dbd0278c9 Mon Sep 17 00:00:00 2001
From: John Ogness <john.ogness@linutronix.de>
Date: Thu, 26 May 2022 22:36:56 +0206
Subject: [PATCH] Revert "printk: wake up all waiters"

This reverts commit 938ba4084abcf6fdd21d9078513c52f8fb9b00d0.

The wait queue @log_wait never has exclusive waiters, so there
is no need to use wake_up_interruptible_all(). Using
wake_up_interruptible() was the correct function to wake all
waiters.

Since there are no exclusive waiters, erroneously changing
wake_up_interruptible() to wake_up_interruptible_all() did not
result in any behavior change. However, using
wake_up_interruptible_all() on a wait queue without exclusive
waiters is fundamentally wrong.

Go back to using wake_up_interruptible() to wake all waiters.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220526203056.81123-1-john.ogness@linutronix.de
---
 kernel/printk/printk.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index a3e1035929b04..ea3dd55709e72 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -3904,7 +3904,7 @@ static void wake_up_klogd_work_func(struct irq_work *irq_work)
 	}
 
 	if (pending & PRINTK_PENDING_WAKEUP)
-		wake_up_interruptible_all(&log_wait);
+		wake_up_interruptible(&log_wait);
 }
 
 static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) =
-- 
GitLab