| Message ID | 20250308144839.33849-1-qasdev00@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | drm/msm/dpu: reorder pointer operations after sanity checks to avoid NULL deref | expand |
On Sat, Mar 08, 2025 at 02:48:39PM +0000, Qasim Ijaz wrote: > _dpu_encoder_trigger_start dereferences "struct dpu_encoder_phys *phys" > before the sanity checks which can lead to a NULL pointer dereference if > phys is NULL. > > Fix this by reordering the dereference after the sanity checks. > > Signed-off-by: Qasim Ijaz <qasdev00@gmail.com> > Fixes: 8144d17a81d9 ("drm/msm/dpu: Skip trigger flush and start for CWB") Your SoB should be the last tag. Fixes comes before it. > --- > drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c > index 0eed93a4d056..ba8b2a163232 100644 > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c > @@ -1667,8 +1667,6 @@ static void _dpu_encoder_trigger_flush(struct drm_encoder *drm_enc, > */ > static void _dpu_encoder_trigger_start(struct dpu_encoder_phys *phys) > { > - struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(phys->parent); > - > if (!phys) { > DPU_ERROR("invalid argument(s)\n"); > return; > @@ -1679,6 +1677,8 @@ static void _dpu_encoder_trigger_start(struct dpu_encoder_phys *phys) > return; > } > > + struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(phys->parent); > + I'm not a fan of having variable defs in the middle of the code. Please keep the def at the top and assign it here. > if (phys->parent->encoder_type == DRM_MODE_ENCODER_VIRTUAL && > dpu_enc->cwb_mask) { > DPU_DEBUG("encoder %d CWB enabled, skipping\n", DRMID(phys->parent)); > -- > 2.39.5 >
…
> Fix this by reordering the dereference after the sanity checks.
Another wording suggestion:
Thus move the assignment of the variable “dpu_enc” behind a null pointer check.
Would an other summary phrase be nicer?
Regards,
Markus
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c index 0eed93a4d056..ba8b2a163232 100644 --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c @@ -1667,8 +1667,6 @@ static void _dpu_encoder_trigger_flush(struct drm_encoder *drm_enc, */ static void _dpu_encoder_trigger_start(struct dpu_encoder_phys *phys) { - struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(phys->parent); - if (!phys) { DPU_ERROR("invalid argument(s)\n"); return; @@ -1679,6 +1677,8 @@ static void _dpu_encoder_trigger_start(struct dpu_encoder_phys *phys) return; } + struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(phys->parent); + if (phys->parent->encoder_type == DRM_MODE_ENCODER_VIRTUAL && dpu_enc->cwb_mask) { DPU_DEBUG("encoder %d CWB enabled, skipping\n", DRMID(phys->parent));
_dpu_encoder_trigger_start dereferences "struct dpu_encoder_phys *phys" before the sanity checks which can lead to a NULL pointer dereference if phys is NULL. Fix this by reordering the dereference after the sanity checks. Signed-off-by: Qasim Ijaz <qasdev00@gmail.com> Fixes: 8144d17a81d9 ("drm/msm/dpu: Skip trigger flush and start for CWB") --- drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)