From: John Ogness <john.ogness@linutronix.de>
Date: Mon, 26 Feb 2024 12:01:24 +0000 (+0106)
Subject: printk: Update @console_may_schedule in console_trylock_spinning()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=8076972468584d4a21dab9aa50e388b3ea9ad8c7;p=linux.git

printk: Update @console_may_schedule in console_trylock_spinning()

console_trylock_spinning() may takeover the console lock from a
schedulable context. Update @console_may_schedule to make sure it
reflects a trylock acquire.

Reported-by: Mukesh Ojha <quic_mojha@quicinc.com>
Closes: https://lore.kernel.org/lkml/20240222090538.23017-1-quic_mojha@quicinc.com
Fixes: dbdda842fe96 ("printk: Add console owner and waiter logic to load balance console writes")
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/875xybmo2z.fsf@jogness.linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>
---

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index b06f63e276c1f..612c73333848e 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2009,6 +2009,12 @@ static int console_trylock_spinning(void)
 	 */
 	mutex_acquire(&console_lock_dep_map, 0, 1, _THIS_IP_);
 
+	/*
+	 * Update @console_may_schedule for trylock because the previous
+	 * owner may have been schedulable.
+	 */
+	console_may_schedule = 0;
+
 	return 1;
 }