On 2022-02-15, Sebastian Siewior <bigeasy@xxxxxxxxxxxxx> wrote: >> From: Jiri Kosina <jkosina@xxxxxxx> >> >> drm_fb_helper_damage() is acquiring spinlock_t (helper->damage_lock), >> while it can be called from contexts where raw_spinlock_t is held (e.g. >> console_owner lock obtained on vprintk_emit() codepath). >> >> As the critical sections protected by damage_lock are super-tiny, let's >> fix this by converting it to raw_spinlock_t in order not to violate >> PREEMPT_RT-imposed lock nesting rules. >> >> This fixes the splat below. >> >> ============================= >> [ BUG: Invalid wait context ] >> 5.17.0-rc4-00002-gd567f5db412e #1 Not tainted > > rc4. Is this also the case in the RT tree which includes John's printk > changes? In the RT tree, the fbcon's write() callback is only called in preemptible() contexts. So this is only a mainline issue. The series I recently posted to LKML [0] should also address this issue (if/when it gets accepted). John [0] https://lore.kernel.org/lkml/20220207194323.273637-1-john.ogness@xxxxxxxxxxxxx
