6.14-stable review patch. If anyone has any objections, please let me know.
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From: Brendan King Brendan.King@imgtec.com
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 brendan.king@imgtec.com Reviewed-by: Matt Coster matt.coster@imgtec.com Link: https://lore.kernel.org/r/20250318-ddkopsrc-1337-use-after-free-in-pvr_queue... Signed-off-by: Matt Coster matt.coster@imgtec.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/imagination/pvr_job.c | 7 +++++++ drivers/gpu/drm/imagination/pvr_queue.c | 4 ++++ 2 files changed, 11 insertions(+)
--- a/drivers/gpu/drm/imagination/pvr_job.c +++ b/drivers/gpu/drm/imagination/pvr_job.c @@ -677,6 +677,13 @@ pvr_jobs_link_geom_frag(struct pvr_job_d 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++; } --- 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 dr 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); }