[PATCH v2] drm/imagination: Fix double call to drm_sched_entity_fini()
From: Brajesh Gupta
Date: Thu Jun 11 2026 - 01:38:03 EST
Call sequence of double call:
pvr_context_destroy
pvr_context_kill_queues
pvr_queue_kill
drm_sched_entity_destroy
drm_sched_entity_fini // here
pvr_context_put
kref_put(..., pvr_context_release)
pvr_context_destroy_queues
pvr_queue_destroy
drm_sched_entity_fini // here
Call to drm_sched_entity_destroy() from pvr_context_kill_queues() calls
drm_sched_entity_flush() + drm_sched_entity_fini().
drm_sched_entity_flush() ensures all pending jobs are completed and
drm_sched_entity_fini() ensures no further submission is allowed as
per expectation from pvr_context_kill_queues(). Drop the extra
call to drm_sched_entity_fini().
Stack trace for issue with addition of refcounting for DRM entity
stats in commit fd177135f0e6 ("drm/sched: Account entity GPU time"):
[ 789.490527] ------------[ cut here ]------------
[ 789.490559] refcount_t: underflow; use-after-free.
[ 789.490657] WARNING: lib/refcount.c:28 at refcount_warn_saturate+0xf4/0x144, CPU#0: kworker/u16:1/440
[ 789.490695] Modules linked in: powervr drm_gpuvm drm_exec gpu_sched drm_shmem_helper xhci_plat_hcd xhci_hcd dwc3 usbcore usb_common snd_soc_simple_card snd_soc_simple_card_utils sa2ul sha512 sha256 dwc3_am62 sha1 authenc rti_wdt libsha512 at24 sch_fq_codel fuse dm_mod ipv6
[ 789.490798] CPU: 0 UID: 0 PID: 440 Comm: kworker/u16:1 Not tainted 7.0.0-rc7-02049-g5e2c0700091b #22 PREEMPT
[ 789.490809] Hardware name: Texas Instruments AM625 SK (DT)
[ 789.490815] Workqueue: powervr-sched pvr_queue_fence_release_work [powervr]
[ 789.490868] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 789.490876] pc : refcount_warn_saturate+0xf4/0x144
[ 789.490884] lr : refcount_warn_saturate+0xf4/0x144
[ 789.490892] sp : ffff8000822cbcc0
[ 789.490895] x29: ffff8000822cbcc0 x28: 0000000000000000 x27: 0000000000000000
[ 789.490909] x26: 0000000000000000 x25: ffff800081b1e338 x24: ffff000004541405
[ 789.490922] x23: ffff000004bea950 x22: ffff00000042e400 x21: ffff000007123e30
[ 789.490935] x20: ffff000007123000 x19: ffff000007a80d50 x18: fffffffffffe7768
[ 789.490948] x17: 74736574202c6e6f x16: 697461746e656d65 x15: ffff800081b269f0
[ 789.490962] x14: 0000000000000030 x13: ffff800081b26a70 x12: 0000000000000211
[ 789.490975] x11: 00000000000000c0 x10: 0000000000000b50 x9 : ffff8000822cbb30
[ 789.490988] x8 : ffff0000014e7bb0 x7 : ffff00007725e780 x6 : 0000000372a05f49
[ 789.491001] x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000010
[ 789.491013] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000014e7000
[ 789.491027] Call trace:
[ 789.491032] refcount_warn_saturate+0xf4/0x144 (P)
[ 789.491043] drm_sched_entity_fini+0x164/0x18c [gpu_sched]
[ 789.491081] pvr_queue_destroy+0x64/0x134 [powervr]
[ 789.491110] pvr_context_destroy_queues+0x34/0x64 [powervr]
[ 789.491138] pvr_context_release+0x70/0xac [powervr]
[ 789.491166] pvr_context_put.part.0+0x5c/0x7c [powervr]
[ 789.491193] pvr_context_put+0x14/0x24 [powervr]
[ 789.491221] pvr_queue_fence_release_work+0x20/0x38 [powervr]
[ 789.491249] process_one_work+0x160/0x4c4
[ 789.491264] worker_thread+0x188/0x310
[ 789.491276] kthread+0x130/0x13c
[ 789.491287] ret_from_fork+0x10/0x20
[ 789.491300] ---[ end trace 0000000000000000 ]---
Signed-off-by: Brajesh Gupta <brajesh.gupta@xxxxxxxxxx>
Fixes: eaf01ee5ba28 ("drm/imagination: Implement job submission and scheduling")
References: fd177135f0e6 ("drm/sched: Account entity GPU time")
---
Changes in v2:
- Fixed memory leak identified in following error path handling of pvr_context_create():
- pvr_context_create()
- ...
- err_destroy_queues:
- pvr_context_destroy_queues()
- pvr_queue_destroy()
- Link to v1: https://lore.kernel.org/r/20260610-b4-sched_fix-v1-1-c5977a6e0b4c@xxxxxxxxxx
---
drivers/gpu/drm/imagination/pvr_context.c | 23 +++++++++++++++++++----
drivers/gpu/drm/imagination/pvr_queue.c | 1 -
2 files changed, 19 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/imagination/pvr_context.c b/drivers/gpu/drm/imagination/pvr_context.c
index eba4694400b5..f11a45d04632 100644
--- a/drivers/gpu/drm/imagination/pvr_context.c
+++ b/drivers/gpu/drm/imagination/pvr_context.c
@@ -161,21 +161,36 @@ ctx_fw_data_init(void *cpu_ptr, void *priv)
/**
* pvr_context_destroy_queues() - Destroy all queues attached to a context.
* @ctx: Context to destroy queues on.
+ * @queue_entity_fini: Corresponding queues of context to be released for
+ * failure path in context creation.
*
* Should be called when the last reference to a context object is dropped.
* It releases all resources attached to the queues bound to this context.
*/
-static void pvr_context_destroy_queues(struct pvr_context *ctx)
+static void pvr_context_destroy_queues(struct pvr_context *ctx, bool queue_entity_fini)
{
switch (ctx->type) {
case DRM_PVR_CTX_TYPE_RENDER:
+ if (queue_entity_fini) {
+ drm_sched_entity_fini(&ctx->queues.fragment->entity);
+ drm_sched_entity_fini(&ctx->queues.geometry->entity)
+ }
+
pvr_queue_destroy(ctx->queues.fragment);
pvr_queue_destroy(ctx->queues.geometry);
break;
+
case DRM_PVR_CTX_TYPE_COMPUTE:
+ if (queue_entity_fini)
+ drm_sched_entity_fini(&ctx->queues.compute->entity);
+
pvr_queue_destroy(ctx->queues.compute);
break;
+
case DRM_PVR_CTX_TYPE_TRANSFER_FRAG:
+ if (queue_entity_fini)
+ drm_sched_entity_fini(&ctx->queues.transfer->entity);
+
pvr_queue_destroy(ctx->queues.transfer);
break;
}
@@ -240,7 +255,7 @@ static int pvr_context_create_queues(struct pvr_context *ctx,
return -EINVAL;
err_destroy_queues:
- pvr_context_destroy_queues(ctx);
+ pvr_context_destroy_queues(ctx, false);
return err;
}
@@ -349,7 +364,7 @@ int pvr_context_create(struct pvr_file *pvr_file, struct drm_pvr_ioctl_create_co
pvr_fw_object_destroy(ctx->fw_obj);
err_destroy_queues:
- pvr_context_destroy_queues(ctx);
+ pvr_context_destroy_queues(ctx, true);
err_free_ctx_id:
/*
@@ -384,7 +399,7 @@ pvr_context_release(struct kref *ref_count)
spin_unlock(&pvr_dev->ctx_list_lock);
xa_erase(&pvr_dev->ctx_ids, ctx->ctx_id);
- pvr_context_destroy_queues(ctx);
+ pvr_context_destroy_queues(ctx, false);
pvr_fw_object_destroy(ctx->fw_obj);
kfree(ctx->data);
pvr_vm_context_put(ctx->vm_ctx);
diff --git a/drivers/gpu/drm/imagination/pvr_queue.c b/drivers/gpu/drm/imagination/pvr_queue.c
index 7ed60e1c1a86..c163f8da2106 100644
--- a/drivers/gpu/drm/imagination/pvr_queue.c
+++ b/drivers/gpu/drm/imagination/pvr_queue.c
@@ -1453,7 +1453,6 @@ void pvr_queue_destroy(struct pvr_queue *queue)
mutex_unlock(&queue->ctx->pvr_dev->queues.lock);
drm_sched_fini(&queue->scheduler);
- drm_sched_entity_fini(&queue->entity);
if (WARN_ON(queue->last_queued_job_scheduled_fence))
dma_fence_put(queue->last_queued_job_scheduled_fence);
---
base-commit: 61de054a772a1feda6364931ab1baf9038abf1c8
change-id: 20260610-b4-sched_fix-ac3b920f475b
Best regards,
--
Brajesh Gupta <brajesh.gupta@xxxxxxxxxx>