Re: [PATCH 2/4] drm/log: Do not hold lock across drm_client_release()

[Jocelyn Falempe]

On 09/10/2025 15:16, Thomas Zimmermann wrote:
When calling drm_client_release(), the client is already quiescent.
Internal locks should therefore be dropped before the caller releases
the client.
In the case of the DRM log, concurrency originates from the console or
from client events. The console has been unregistered in the previous
line. The caller of the unregister callback, drm_log_client_unregister(),
holds clientlist_mutex from struct drm_device to protect against concurrent
client events. It is therefore safe to release the client without holding
locks.

Thanks, I agree, it should be safe to move drm_client_release() after 
the lock.

Reviewed-by: Jocelyn Falempe <jfale...@redhat.com>>
Signed-off-by: Thomas Zimmermann <tzimmerm...@suse.de>
---
  drivers/gpu/drm/clients/drm_log.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/clients/drm_log.c 
b/drivers/gpu/drm/clients/drm_log.c
index d239f1e3c456..116e0ef9ae5d 100644
--- a/drivers/gpu/drm/clients/drm_log.c
+++ b/drivers/gpu/drm/clients/drm_log.c
@@ -302,8 +302,8 @@ static void drm_log_client_unregister(struct drm_client_dev 
*client)
  
  	mutex_lock(&dlog->lock);
        drm_log_free_scanout(client);
-       drm_client_release(client);
        mutex_unlock(&dlog->lock);
+       drm_client_release(client);
        kfree(dlog);
        drm_dbg(dev, "Unregistered with drm log\n");
  }