From c90b95e12eb88d23740e5ea2c43d71675d17ac8d Mon Sep 17 00:00:00 2001 From: Brendan King Date: Tue, 18 Mar 2025 14:53:13 +0000 Subject: [PATCH] drm/imagination: take paired job reference commit 4ba2abe154ef68f9612eee9d6fbfe53a1736b064 upstream. For paired jobs, have the fragment job take a reference on the geometry job, so that the geometry job cannot be freed until the fragment job has finished with it. The geometry job structure is accessed when the fragment job is being prepared by the GPU scheduler. Taking the reference prevents the geometry job being freed until the fragment job no longer requires it. Fixes a use after free bug detected by KASAN: [ 124.256386] BUG: KASAN: slab-use-after-free in pvr_queue_prepare_job+0x108/0x868 [powervr] [ 124.264893] Read of size 1 at addr ffff0000084cb960 by task kworker/u16:4/63 Cc: stable@vger.kernel.org Fixes: eaf01ee5ba28 ("drm/imagination: Implement job submission and scheduling") Signed-off-by: Brendan King Reviewed-by: Matt Coster Link: https://lore.kernel.org/r/20250318-ddkopsrc-1337-use-after-free-in-pvr_queue_prepare_job-v1-1-80fb30d044a6@imgtec.com Signed-off-by: Matt Coster Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/imagination/pvr_job.c | 7 +++++++ drivers/gpu/drm/imagination/pvr_queue.c | 4 ++++ 2 files changed, 11 insertions(+) diff --git a/drivers/gpu/drm/imagination/pvr_job.c b/drivers/gpu/drm/imagination/pvr_job.c index 78c2f3c6dce01..6a15c1d2d871d 100644 --- a/drivers/gpu/drm/imagination/pvr_job.c +++ b/drivers/gpu/drm/imagination/pvr_job.c @@ -684,6 +684,13 @@ pvr_jobs_link_geom_frag(struct pvr_job_data *job_data, u32 *job_count) geom_job->paired_job = frag_job; frag_job->paired_job = geom_job; + /* The geometry job pvr_job structure is used when the fragment + * job is being prepared by the GPU scheduler. Have the fragment + * job hold a reference on the geometry job to prevent it being + * freed until the fragment job has finished with it. + */ + pvr_job_get(geom_job); + /* Skip the fragment job we just paired to the geometry job. */ i++; } diff --git a/drivers/gpu/drm/imagination/pvr_queue.c b/drivers/gpu/drm/imagination/pvr_queue.c index 87780cc7c0c32..130473cfdfc9b 100644 --- a/drivers/gpu/drm/imagination/pvr_queue.c +++ b/drivers/gpu/drm/imagination/pvr_queue.c @@ -866,6 +866,10 @@ static void pvr_queue_free_job(struct drm_sched_job *sched_job) struct pvr_job *job = container_of(sched_job, struct pvr_job, base); drm_sched_job_cleanup(sched_job); + + if (job->type == DRM_PVR_JOB_TYPE_FRAGMENT && job->paired_job) + pvr_job_put(job->paired_job); + job->paired_job = NULL; pvr_job_put(job); }