Re: [PATCH V3] accel/amdxdna: Prevent PM resume deadlock in hwctx_sync_debug_bo()

[Lizhi Hou]

Applied to drm-misc-fixes

On 7/6/26 15:34, Max Zhen wrote:

On 6/16/2026 Tue 14:24, Lizhi Hou wrote:

amdxdna_hwctx_sync_debug_bo() invokes the hardware hwctx_sync_debug_bo()
callback while holding xdna->dev_lock.

The callback may call amdxdna_cmd_submit(), which in turn calls
amdxdna_pm_resume_get(). If the device is suspended,
amdxdna_pm_resume_get() may synchronously execute amdxdna_pm_resume(),
which also acquires xdna->dev_lock, resulting in a deadlock.

Avoid the deadlock by calling amdxdna_pm_resume_get() before holding
xdna->dev_lock in both amdxdna_hwctx_sync_debug_bo() and
amdxdna_drm_config_hwctx_ioctl()

Fixes: 7ea046838021 ("accel/amdxdna: Support firmware debug buffer")
Signed-off-by: Lizhi Hou <lizhi....@amd.com>

Reviewed-by: Max Zhen <max.z...@amd.com>

---
V2:
   Fix jumping forward over the guard(mutex) declaration.
V3:
   Fix the same in amdxdna_drm_config_hwctx_ioctl().

  drivers/accel/amdxdna/amdxdna_ctx.c | 26 ++++++++++++++++++++++----
  1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/drivers/accel/amdxdna/amdxdna_ctx.c b/drivers/accel/amdxdna/amdxdna_ctx.c

index ff6c3e8e5a15..2ab4443e7094 100644
--- a/drivers/accel/amdxdna/amdxdna_ctx.c
+++ b/drivers/accel/amdxdna/amdxdna_ctx.c

@@ -356,16 +356,25 @@ int amdxdna_drm_config_hwctx_ioctl(struct drm_device *dev, void *data, struct dr

          return -EINVAL;
      }
  -    guard(mutex)(&xdna->dev_lock);
+    ret = amdxdna_pm_resume_get(xdna);
+    if (ret) {
+        XDNA_ERR(xdna, "Resume failed, ret %d", ret);
+        goto free_buf;
+    }
+
+    mutex_lock(&xdna->dev_lock);
      hwctx = xa_load(&client->hwctx_xa, args->handle);
      if (!hwctx) {

          XDNA_DBG(xdna, "PID %d failed to get hwctx %d", client->pid, args->handle);

          ret = -EINVAL;
-        goto free_buf;
+        goto unlock;
      }

        ret = xdna->dev_info->ops->hwctx_config(hwctx, args->param_type, val, buf, buf_size);

  +unlock:
+    mutex_unlock(&xdna->dev_lock);
+    amdxdna_pm_suspend_put(xdna);
  free_buf:
      kfree(buf);
      return ret;

@@ -386,16 +395,25 @@ int amdxdna_hwctx_sync_debug_bo(struct amdxdna_client *client, u32 debug_bo_hdl)

      if (!gobj)
          return -EINVAL;
  +    ret = amdxdna_pm_resume_get(xdna);
+    if (ret) {
+        XDNA_ERR(xdna, "Resume failed, ret %d", ret);
+        goto put_obj;
+    }
+
      abo = to_xdna_obj(gobj);
-    guard(mutex)(&xdna->dev_lock);
+    mutex_lock(&xdna->dev_lock);
      hwctx = xa_load(&client->hwctx_xa, abo->assigned_hwctx);
      if (!hwctx) {
          ret = -EINVAL;
-        goto put_obj;
+        goto unlock;
      }

        ret = xdna->dev_info->ops->hwctx_sync_debug_bo(hwctx, debug_bo_hdl);

  +unlock:
+    mutex_unlock(&xdna->dev_lock);
+    amdxdna_pm_suspend_put(xdna);
  put_obj:
      drm_gem_object_put(gobj);
      return ret;