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@redhat.com --- 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; }