On Tue, Oct 31, 2017 at 03:28:01PM +0200, Ville Syrjälä wrote: > On Tue, Oct 31, 2017 at 11:55:35AM +0000, Chris Wilson wrote: > > To acquire all modeset locks requires a ww_ctx to be allocated. As this > > is the legacy path and the allocation small, to reduce the changes > > required (and complex untested error handling) to the legacy drivers, we > > simply assume that the allocation succeeds. At present, it relies on the > > too-small-to-fail rule, but syzbot found that by injecting a failure > > here we would hit the WARN. Document that this allocation must succeed > > with __GFP_NOFAIL. Note that for atomic drivers at least all the core/helper paths are fixed up correctly. But e.g. i915 has still plenty of callsites in its own code, mostly debugfs. > > Reported-by: syzbot (syzkaller) > > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > > Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> > > Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Applied, thanks. -Daniel > > > --- > > Resent to the right list! > > --- > > drivers/gpu/drm/drm_modeset_lock.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/drm_modeset_lock.c b/drivers/gpu/drm/drm_modeset_lock.c > > index e123497da0ca..963e23db0fe7 100644 > > --- a/drivers/gpu/drm/drm_modeset_lock.c > > +++ b/drivers/gpu/drm/drm_modeset_lock.c > > @@ -93,7 +93,7 @@ void drm_modeset_lock_all(struct drm_device *dev) > > struct drm_modeset_acquire_ctx *ctx; > > int ret; > > > > - ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); > > + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL | __GFP_NOFAIL); > > if (WARN_ON(!ctx)) > > return; > > > > -- > > 2.15.0.rc2 > > > > _______________________________________________ > > dri-devel mailing list > > dri-devel@xxxxxxxxxxxxxxxxxxxxx > > https://lists.freedesktop.org/mailman/listinfo/dri-devel > > -- > Ville Syrjälä > Intel OTC -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
