For a while now it's been allowed for a MMU context to outlive it's corresponding panfrost_priv, however the job structure still references panfrost_priv to get hold of the MMU context. If panfrost_priv has been freed this is a use-after-free which I've been able to trigger resulting in a splat.
To fix this, drop the reference to panfrost_priv in the job structure and add a direct reference to the MMU structure which is what's actually needed.
Fixes: 7fdc48cc63a3 ("drm/panfrost: Make sure MMU context lifetime is not bound to panfrost_priv") Signed-off-by: Steven Price steven.price@arm.com --- drivers/gpu/drm/panfrost/panfrost_drv.c | 5 +++-- drivers/gpu/drm/panfrost/panfrost_job.c | 6 +++--- drivers/gpu/drm/panfrost/panfrost_job.h | 2 +- 3 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c index 7fcbc2a5b6cd..087e69b98d06 100644 --- a/drivers/gpu/drm/panfrost/panfrost_drv.c +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c @@ -233,6 +233,7 @@ static int panfrost_ioctl_submit(struct drm_device *dev, void *data, struct drm_file *file) { struct panfrost_device *pfdev = dev->dev_private; + struct panfrost_file_priv *file_priv = file->driver_priv; struct drm_panfrost_submit *args = data; struct drm_syncobj *sync_out = NULL; struct panfrost_job *job; @@ -262,12 +263,12 @@ static int panfrost_ioctl_submit(struct drm_device *dev, void *data, job->jc = args->jc; job->requirements = args->requirements; job->flush_id = panfrost_gpu_get_latest_flush_id(pfdev); - job->file_priv = file->driver_priv; + job->mmu = file_priv->mmu;
slot = panfrost_job_get_slot(job);
ret = drm_sched_job_init(&job->base, - &job->file_priv->sched_entity[slot], + &file_priv->sched_entity[slot], NULL); if (ret) goto out_put_job; diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c index fda5871aebe3..7c4208476fbd 100644 --- a/drivers/gpu/drm/panfrost/panfrost_job.c +++ b/drivers/gpu/drm/panfrost/panfrost_job.c @@ -201,7 +201,7 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js) return; }
- cfg = panfrost_mmu_as_get(pfdev, job->file_priv->mmu); + cfg = panfrost_mmu_as_get(pfdev, job->mmu);
job_write(pfdev, JS_HEAD_NEXT_LO(js), lower_32_bits(jc_head)); job_write(pfdev, JS_HEAD_NEXT_HI(js), upper_32_bits(jc_head)); @@ -435,7 +435,7 @@ static void panfrost_job_handle_err(struct panfrost_device *pfdev, job->jc = 0; }
- panfrost_mmu_as_put(pfdev, job->file_priv->mmu); + panfrost_mmu_as_put(pfdev, job->mmu); panfrost_devfreq_record_idle(&pfdev->pfdevfreq);
if (signal_fence) @@ -456,7 +456,7 @@ static void panfrost_job_handle_done(struct panfrost_device *pfdev, * happen when we receive the DONE interrupt while doing a GPU reset). */ job->jc = 0; - panfrost_mmu_as_put(pfdev, job->file_priv->mmu); + panfrost_mmu_as_put(pfdev, job->mmu); panfrost_devfreq_record_idle(&pfdev->pfdevfreq);
dma_fence_signal_locked(job->done_fence); diff --git a/drivers/gpu/drm/panfrost/panfrost_job.h b/drivers/gpu/drm/panfrost/panfrost_job.h index 77e6d0e6f612..8becc1ba0eb9 100644 --- a/drivers/gpu/drm/panfrost/panfrost_job.h +++ b/drivers/gpu/drm/panfrost/panfrost_job.h @@ -17,7 +17,7 @@ struct panfrost_job { struct kref refcount;
struct panfrost_device *pfdev; - struct panfrost_file_priv *file_priv; + struct panfrost_mmu *mmu;
/* Fence to be signaled by IRQ handler when the job is complete. */ struct dma_fence *done_fence;