Taking over the console involves allocating mem with GFP_KERNEL, talking
to drm drivers, etc. So this should not be done from an atomic context.
But the console-output trigger deferred console takeover may happen from an
atomic context, which leads to "BUG: sleeping function called from invalid
context" errors.
This commit fixes these errors by doing the deferred takeover from a
workqueue.
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
Changes in v2:
-Add a comment fbcon.c and the commit message about why we need to use
in_atomic here, no functional changes
Changes in v3:
-It is not possible to reliable detect if we're running in an atomic
context, simply always do the takeover from a worker
---
drivers/video/fbdev/core/fbcon.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index ef8b2d0b7071..5581dec102aa 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -3592,7 +3592,20 @@ static int fbcon_init_device(void)
}
#ifdef CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER
+static void fbcon_register_existing_fbs(struct work_struct *work)
+{
+ int i;
+
+ console_lock();
+
+ for_each_registered_fb(i)
+ fbcon_fb_registered(registered_fb[i]);
+
+ console_unlock();
+}
+
static struct notifier_block fbcon_output_nb;
+static DECLARE_WORK(fbcon_deferred_takeover_work, fbcon_register_existing_fbs);
static int fbcon_output_notifier(struct notifier_block *nb,
unsigned long action, void *data)
@@ -3607,8 +3620,8 @@ static int fbcon_output_notifier(struct notifier_block *nb,
deferred_takeover = false;
logo_shown = FBCON_LOGO_DONTSHOW;
- for_each_registered_fb(i)
- fbcon_fb_registered(registered_fb[i]);
+ /* We may get called in atomic context */
+ schedule_work(&fbcon_deferred_takeover_work);
return NOTIFY_OK;
}
--
2.18.0
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