[PATCH V1] accel/amdxdna: Fix deadlock on debug BO command timeout

[Lizhi Hou <lizhi.hou@amd.com>]

Both amdxdna_hwctx_sync_debug_bo() and amdxdna_drm_config_hwctx_ioctl()
hold xdna->dev_lock while invoking backend operations. If the hardware
hangs, aie2_cmd_wait() blocks waiting for a firmware response. When the
DRM scheduler timeout expires, aie2_sched_job_timedout() is invoked to
reset the hardware. However, the timeout handler also attempts to acquire
dev_lock, resulting in a deadlock.

Avoid this by releasing dev_lock before waiting for the firmware
response and reacquiring it after the wait completes. This allows the
timeout handler to proceed with device recovery when a debug BO command
times out.

Fixes: 7ea046838021 ("accel/amdxdna: Support firmware debug buffer")
Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
---
 drivers/accel/amdxdna/aie2_ctx.c    | 5 ++++-
 drivers/accel/amdxdna/amdxdna_ctx.c | 6 ++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/accel/amdxdna/aie2_ctx.c b/drivers/accel/amdxdna/aie2_ctx.c
index 7bf635634e64..30ccb8d5e23d 100644
--- a/drivers/accel/amdxdna/aie2_ctx.c
+++ b/drivers/accel/amdxdna/aie2_ctx.c
@@ -900,13 +900,16 @@ static int aie2_hwctx_cu_config(struct amdxdna_hwctx *hwctx, void *buf, u32 size
 static void aie2_cmd_wait(struct amdxdna_hwctx *hwctx, u64 seq)
 {
 	struct dma_fence *out_fence = aie2_cmd_get_out_fence(hwctx, seq);
+	struct amdxdna_dev *xdna = hwctx->client->xdna;
 
 	if (!out_fence) {
-		XDNA_ERR(hwctx->client->xdna, "Failed to get fence");
+		XDNA_ERR(xdna, "Failed to get fence");
 		return;
 	}
 
+	mutex_unlock(&xdna->dev_lock);
 	dma_fence_wait_timeout(out_fence, false, MAX_SCHEDULE_TIMEOUT);
+	mutex_lock(&xdna->dev_lock);
 	dma_fence_put(out_fence);
 }
 
diff --git a/drivers/accel/amdxdna/amdxdna_ctx.c b/drivers/accel/amdxdna/amdxdna_ctx.c
index 67a2abcf173e..9ae19393e488 100644
--- a/drivers/accel/amdxdna/amdxdna_ctx.c
+++ b/drivers/accel/amdxdna/amdxdna_ctx.c
@@ -310,6 +310,7 @@ int amdxdna_drm_destroy_hwctx_ioctl(struct drm_device *dev, void *data, struct d
 	if (!drm_dev_enter(dev, &idx))
 		return -ENODEV;
 
+	mutex_lock(&xdna->client_lock);
 	mutex_lock(&xdna->dev_lock);
 	hwctx = xa_erase(&client->hwctx_xa, args->handle);
 	if (!hwctx) {
@@ -328,6 +329,7 @@ int amdxdna_drm_destroy_hwctx_ioctl(struct drm_device *dev, void *data, struct d
 	XDNA_DBG(xdna, "PID %d destroyed HW context %d", client->pid, args->handle);
 out:
 	mutex_unlock(&xdna->dev_lock);
+	mutex_unlock(&xdna->client_lock);
 	drm_dev_exit(idx);
 	return ret;
 }
@@ -388,6 +390,7 @@ int amdxdna_drm_config_hwctx_ioctl(struct drm_device *dev, void *data, struct dr
 		goto free_buf;
 	}
 
+	mutex_lock(&xdna->client_lock);
 	mutex_lock(&xdna->dev_lock);
 	hwctx = xa_load(&client->hwctx_xa, args->handle);
 	if (!hwctx) {
@@ -400,6 +403,7 @@ int amdxdna_drm_config_hwctx_ioctl(struct drm_device *dev, void *data, struct dr
 
 unlock:
 	mutex_unlock(&xdna->dev_lock);
+	mutex_unlock(&xdna->client_lock);
 	amdxdna_pm_suspend_put(xdna);
 free_buf:
 	kfree(buf);
@@ -428,6 +432,7 @@ int amdxdna_hwctx_sync_debug_bo(struct amdxdna_client *client, u32 debug_bo_hdl)
 	}
 
 	abo = to_xdna_obj(gobj);
+	mutex_lock(&xdna->client_lock);
 	mutex_lock(&xdna->dev_lock);
 	hwctx = xa_load(&client->hwctx_xa, abo->assigned_hwctx);
 	if (!hwctx) {
@@ -439,6 +444,7 @@ int amdxdna_hwctx_sync_debug_bo(struct amdxdna_client *client, u32 debug_bo_hdl)
 
 unlock:
 	mutex_unlock(&xdna->dev_lock);
+	mutex_unlock(&xdna->client_lock);
 	amdxdna_pm_suspend_put(xdna);
 put_obj:
 	drm_gem_object_put(gobj);
-- 
2.34.1