Hi Daniel,
On 5/21/19 4:23 PM, Daniel Vetter wrote: > This is unused code since > > commit 6104c37094e729f3d4ce65797002112735d49cd1 > Author: Daniel Vetter <daniel.vet...@ffwll.ch> > Date: Tue Aug 1 17:32:07 2017 +0200 > > fbcon: Make fbcon a built-time depency for fbdev > > when fbcon was made a compile-time static dependency of fbdev. We > can't exit fbcon anymore without exiting fbdev first, which only works > if all fbdev drivers have unloaded already. Hence this is all dead > code. > > v2: I missed that fbcon_exit is also called from con_deinit stuff, and > there fbcon_has_exited prevents double-cleanup. But we can fix that > by properly resetting con2fb_map[] to all -1, which is used everywhere > else to indicate "no fb_info allocate to this console". With that > change the double-cleanup (which resulted in a module refcount underflow, > among other things) is prevented. > > Aside: con2fb_map is a signed char, so don't register more than 128 fb_info > or hilarity will ensue. > > v3: CI showed me that I still didn't fully understand what's going on > here. The leaked references in con2fb_map have been used upon > rebinding the fb console in fbcon_init. It worked because fbdev > unregistering still cleaned out con2fb_map, and reset it to info_idx. > If the last fbdev driver unregistered, then it also reset info_idx, > and unregistered the fbcon driver. > > Imo that's all a bit fragile, so let's keep the con2fb_map reset to > -1, and in fbcon_init pick info_idx if we're starting fresh. That > means unbinding and rebinding will cleanse the mapping, but why are > you doing that if you want to retain the mapping, so should be fine. > > Also, I think info_idx == -1 is impossible in fbcon_init - we > unregister the fbcon in that case. So catch&warn about that. > > Signed-off-by: Daniel Vetter <daniel.vet...@intel.com> > Cc: Maarten Lankhorst <maarten.lankho...@linux.intel.com> > Cc: Bartlomiej Zolnierkiewicz <b.zolnier...@samsung.com> > Cc: Daniel Vetter <daniel.vet...@ffwll.ch> > Cc: Hans de Goede <hdego...@redhat.com> > Cc: "Noralf Trønnes" <nor...@tronnes.org> > Cc: Yisheng Xie <ys...@foxmail.com> > Cc: Konstantin Khorenko <khore...@virtuozzo.com> > Cc: Prarit Bhargava <pra...@redhat.com> > Cc: Kees Cook <keesc...@chromium.org> > --- > drivers/video/fbdev/core/fbcon.c | 39 +++++--------------------------- > 1 file changed, 6 insertions(+), 33 deletions(-) This patch was #09/33 in your patch series, now it is independent change. Do you want me to apply it now or should I wait for the new version of the whole series? [ I looked at all patches in the series and they look fine to me. After outstanding issues are fixed I'll be happy to apply them all to fbdev-for-next (I can create immutable branch if needed). ] Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics
