Commit 45f99d44 authored Feb 26, 2024 by John Ogness Committed by Greg Kroah-Hartman Apr 13, 2024

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 <quic_mojha@quicinc.com>
Closes: https://lore.kernel.org/lkml/20240222090538.23017-1-quic_mojha@quicinc.com


Fixes: dbdda842 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 10ca82af

kernel/printk/printk.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -1732,6 +1732,12 @@ 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;
		}