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drm/imagination: avoid deadlock on fence release

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Do scheduler queue fence release processing on a workqueue, rather
than in the release function itself.

Fixes deadlock issues such as the following:

[  607.400437] ============================================
[  607.405755] WARNING: possible recursive locking detected
[  607.415500] --------------------------------------------
[  607.420817] weston:zfq0/24149 is trying to acquire lock:
[  607.426131] ffff000017d041a0 (reservation_ww_class_mutex){+.+.}-{3:3}, at: pvr_gem_object_vunmap+0x40/0xc0 [powervr]
[  607.436728]
               but task is already holding lock:
[  607.442554] ffff000017d105a0 (reservation_ww_class_mutex){+.+.}-{3:3}, at: dma_buf_ioctl+0x250/0x554
[  607.451727]
               other info that might help us debug this:
[  607.458245]  Possible unsafe locking scenario:

[  607.464155]        CPU0
[  607.466601]        ----
[  607.469044]   lock(reservation_ww_class_mutex);
[  607.473584]   lock(reservation_ww_class_mutex);
[  607.478114]
                *** DEADLOCK ***

Cc: stable@vger.kernel.org
Fixes: eaf01ee5ba ("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://patchwork.freedesktop.org/patch/msgid/20250226-fence-release-deadlock-v2-1-6fed2fc1fe88@imgtec.com
Signed-off-by: Matt Coster <matt.coster@imgtec.com>
This commit is contained in:
Brendan King
2025-02-26 15:42:19 +00:00
committed by Matt Coster
parent 6b481ab0e6
commit df1a1ed5e1
2 changed files with 15 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/gpu/drm/imagination/pvr_queue.c
+11 -2
View File
@@ -109,12 +109,20 @@ pvr_queue_fence_get_driver_name(struct dma_fence *f)
return PVR_DRIVER_NAME;
}
static void pvr_queue_fence_release_work(struct work_struct *w)
{
struct pvr_queue_fence *fence = container_of(w, struct pvr_queue_fence, release_work);
pvr_context_put(fence->queue->ctx);
dma_fence_free(&fence->base);
}
static void pvr_queue_fence_release(struct dma_fence *f)
{
struct pvr_queue_fence *fence = container_of(f, struct pvr_queue_fence, base);
struct pvr_device *pvr_dev = fence->queue->ctx->pvr_dev;
pvr_context_put(fence->queue->ctx);
dma_fence_free(f);
queue_work(pvr_dev->sched_wq, &fence->release_work);
}
static const char *
@@ -268,6 +276,7 @@ pvr_queue_fence_init(struct dma_fence *f,
pvr_context_get(queue->ctx);
fence->queue = queue;
INIT_WORK(&fence->release_work, pvr_queue_fence_release_work);
dma_fence_init(&fence->base, fence_ops,
&fence_ctx->lock, fence_ctx->id,
atomic_inc_return(&fence_ctx->seqno));
drivers/gpu/drm/imagination/pvr_queue.h
+4
View File
@@ -5,6 +5,7 @@
#define PVR_QUEUE_H
#include <drm/gpu_scheduler.h>
#include <linux/workqueue.h>
#include "pvr_cccb.h"
#include "pvr_device.h"
@@ -63,6 +64,9 @@ struct pvr_queue_fence {
/** @queue: Queue that created this fence. */
struct pvr_queue *queue;
/** @release_work: Fence release work structure. */
struct work_struct release_work;
};
/**