[PATCH 5.4 018/411] fbcon: Consistently protect deferred_takeover with console_lock()

Greg Kroah-Hartman
2022-06-13T10:59:54Z

From: Daniel Vetter <daniel.vetter@ffwll.ch>

[ Upstream commit 43553559121ca90965b572cf8a1d6d0fd618b449 ]

This shouldn't be a problem in practice since until we've actually
taken over the console there's nothing we've registered with the
console/vt subsystem, so the exit/unbind path that check this can't
do the wrong thing. But it's confusing, so fix it by moving it a tad
later.

Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Du Cheng <ducheng2@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Claudio Suarez <cssk@net-c.es>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405210335.3434130-14-daniel.vetter@ffwll.ch
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/video/fbdev/core/fbcon.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 75b770514067..1decded4845f 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -3286,6 +3286,9 @@ static void fbcon_register_existing_fbs(struct work_struct *work)

console_lock();

+ deferred_takeover = false;
+ logo_shown = FBCON_LOGO_DONTSHOW;
+
for_each_registered_fb(i)
fbcon_fb_registered(registered_fb[i]);

@@ -3303,8 +3306,6 @@ static int fbcon_output_notifier(struct notifier_block *nb,
pr_info("fbcon: Taking over console\n");

dummycon_unregister_output_notifier(&fbcon_output_nb);
- deferred_takeover = false;
- logo_shown = FBCON_LOGO_DONTSHOW;

/* We may get called in atomic context */
schedule_work(&fbcon_deferred_takeover_work);
--
2.35.1