Messages in this thread | | | Date | Mon, 11 Apr 2022 03:56:31 +0300 | Subject | Re: [PATCH] dpu1: dpu_encoder: fix a missing check on list iterator | From | Dmitry Baryshkov <> |
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On 27/03/2022 10:32, Xiaomeng Tong wrote: > The bug is here: > cstate = to_dpu_crtc_state(drm_crtc->state); > > For the drm_for_each_crtc(), just like list_for_each_entry(), > the list iterator 'drm_crtc' will point to a bogus position > containing HEAD if the list is empty or no element is found. > This case must be checked before any use of the iterator, > otherwise it will lead to a invalid memory access. > > To fix this bug, use a new variable 'iter' as the list iterator, > while use the origin variable 'drm_crtc' as a dedicated pointer > to point to the found element. > > Cc: stable@vger.kernel.org > Fixes: b107603b4ad0f ("drm/msm/dpu: map mixer/ctl hw blocks in encoder modeset") > Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> --- > drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c > index 1e648db439f9..d3fdb18e96f9 100644 > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c > @@ -965,7 +965,7 @@ static void dpu_encoder_virt_mode_set(struct drm_encoder *drm_enc, > struct dpu_kms *dpu_kms; > struct list_head *connector_list; > struct drm_connector *conn = NULL, *conn_iter; > - struct drm_crtc *drm_crtc; > + struct drm_crtc *drm_crtc = NULL, *iter; > struct dpu_crtc_state *cstate; > struct dpu_global_state *global_state; > struct dpu_hw_blk *hw_pp[MAX_CHANNELS_PER_ENC]; > @@ -1007,9 +1007,14 @@ static void dpu_encoder_virt_mode_set(struct drm_encoder *drm_enc, > return; > } > > - drm_for_each_crtc(drm_crtc, drm_enc->dev) > - if (drm_crtc->state->encoder_mask & drm_encoder_mask(drm_enc)) > + drm_for_each_crtc(iter, drm_enc->dev) > + if (iter->state->encoder_mask & drm_encoder_mask(drm_enc)) { > + drm_crtc = iter; > break; > + } > + > + if (!drm_crtc) > + return; > > /* Query resource that have been reserved in atomic check step. */ > num_pp = dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
-- With best wishes Dmitry
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