Re: Possible deadlock when suspending framebuffer

Paul, fbdev people.. Comments? This was sent to me and lkml, the right
people probably didn't see it.

I doubt it's a big problem in practice, but..

                      Linus

On Tue, Jun 14, 2011 at 6:10 AM, Francis Moreau [off-list ref] wrote:

Hello,

I noticed that a possible deadlock can happen when the current frame
buffering is being suspended and a new frambuffer device is being
registred at the same time.

When suspending the current frambuffer by doing : echo 1

quoted

/sys/class/graphics/fb0/state, the kernel actually takes the

following locks in that order: console_lock, lock_fb_info (see
store_fbstate()).

However when a new framebuffer is coming in, the lock sequence is:
lock_fb_info (taken by do_remove_conflicting_framebuffer()),
console_lock() (taken by unbind_console).

I don't know how this should be fixed though...

Thanks
--
Francis