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: 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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 45f99d441067035dbb3f2a0d9713abe61ea721c5)
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 11173d0..5d379fc 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1693,6 +1693,12 @@ 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;
}