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charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Patchwork-Hint: comment Subject: Re: [Intel-gfx] [PATCH] drm/i915: Fix NULL ptr deref by checking new_crtc_state X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Fri, May 05, 2023 at 02:20:17PM +0300, Lisovskiy, Stanislav wrote: > On Fri, May 05, 2023 at 02:06:34PM +0300, Ville Syrjälä wrote: > > On Fri, May 05, 2023 at 02:05:27PM +0300, Lisovskiy, Stanislav wrote: > > > On Fri, May 05, 2023 at 02:02:43PM +0300, Ville Syrjälä wrote: > > > > On Fri, May 05, 2023 at 01:58:03PM +0300, Lisovskiy, Stanislav wrote: > > > > > On Fri, May 05, 2023 at 01:54:14PM +0300, Ville Syrjälä wrote: > > > > > > On Fri, May 05, 2023 at 11:22:12AM +0300, Stanislav Lisovskiy wrote: > > > > > > > intel_atomic_get_new_crtc_state can return NULL, unless crtc state wasn't > > > > > > > obtained previously with intel_atomic_get_crtc_state, so we must check it > > > > > > > for NULLness here, just as in many other places, where we can't guarantee > > > > > > > that intel_atomic_get_crtc_state was called. > > > > > > > We are currently getting NULL ptr deref because of that, so this fix was > > > > > > > confirmed to help. > > > > > > > > > > > > > > Fixes: 74a75dc90869 ("drm/i915/display: move plane prepare/cleanup to intel_atomic_plane.c") > > > > > > > Signed-off-by: Stanislav Lisovskiy > > > > > > > --- > > > > > > > drivers/gpu/drm/i915/display/intel_atomic_plane.c | 4 ++-- > > > > > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > > > > > > > > > diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c b/drivers/gpu/drm/i915/display/intel_atomic_plane.c > > > > > > > index 9f670dcfe76e..4125ee07a271 100644 > > > > > > > --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c > > > > > > > +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c > > > > > > > @@ -1029,7 +1029,7 @@ intel_prepare_plane_fb(struct drm_plane *_plane, > > > > > > > int ret; > > > > > > > > > > > > > > if (old_obj) { > > > > > > > - const struct intel_crtc_state *crtc_state = > > > > > > > + const struct intel_crtc_state *new_crtc_state = > > > > > > > intel_atomic_get_new_crtc_state(state, > > > > > > > to_intel_crtc(old_plane_state->hw.crtc)); > > > > > > > > > > > > > > @@ -1044,7 +1044,7 @@ intel_prepare_plane_fb(struct drm_plane *_plane, > > > > > > > * This should only fail upon a hung GPU, in which case we > > > > > > > * can safely continue. > > > > > > > */ > > > > > > > - if (intel_crtc_needs_modeset(crtc_state)) { > > > > > > > + if (new_crtc_state && intel_crtc_needs_modeset(new_crtc_state)) { > > > > > > > > > > > > NAK. We need to fix the bug instead of paparing over it. > > > > > > > > > > I had pushed this already. > > > > > > > > It didn't even finish CI. Please revert. > > > > > > Swati did run CI and verified that fix helps. I'm _not_ going to revert. > > > > Fine. I'll do it. > > Problem is that you don't even care to explain, why this fix is wrong, but simply > act in authoritarian way, instead of having constructive discussion. I've explanined this one about a hundred times. The NULL pointer should not happen. Someone needs to actually analyze what is happening instead of just adding randomg NULL checks all over the place. > I told that we had verified the fix and that we always do those checks in > many places anyway where we get new_crtc_state. > However there were no even reasons to reject mentioned here. > I don't really think that bringing personality traits and authoritarian > discussion style is a professional behaviour. > Thanks for cooperation. > > > > > > > > > > > > > > > Moreover as I understand we need to check that new_crtc_state > > > > > for being NULL anyway. We do check it for being NULL in other places. > > > > > But if you have another solution - go for it. > > > > > > > > > > Stan > > > > > > > > > > > > > > > > > > > > > > > ret = i915_sw_fence_await_reservation(&state->commit_ready, > > > > > > > old_obj->base.resv, > > > > > > > false, 0, > > > > > > > -- > > > > > > > 2.37.3 > > > > > > > > > > > > -- > > > > > > Ville Syrjälä > > > > > > Intel > > > > > > > > -- > > > > Ville Syrjälä > > > > Intel > > > > -- > > Ville Syrjälä > > Intel -- Ville Syrjälä Intel