printk: Update @console_may_schedule in console_trylock_spinning()

[ Upstream commit 8076972468584d4a21dab9aa50e388b3ea9ad8c7 ]

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 <[email protected]>
Closes: https://lore.kernel.org/lkml/[email protected]
Fixes: dbdda842fe ("printk: Add console owner and waiter logic to load balance console writes")
Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Mukesh Ojha <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

kernel/printk/printk.c

@@ -1787,6 +1787,12 @@ 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;
 }