drm_bridge_attach() modifies the encoder bridge chain, so take a mutex around such operations to allow users of the chain to protect themselves from chain modifications while iterating.
Reviewed-by: Maxime Ripard <[email protected]> Signed-off-by: Luca Ceresoli <[email protected]> --- Changes in v3: - Lock encoder->bridge_chain_mutex directly, no wrappers Changes in v2: - Removed comment before on drm_bridge_detach() --- drivers/gpu/drm/drm_bridge.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 8f355df883d8ac8de9d361ec302f4ccbf3bca0d6..c8389383e0d286c0d576ae1864ee783e002d44be 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -462,10 +462,12 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge, bridge->dev = encoder->dev; bridge->encoder = encoder; + mutex_lock(&encoder->bridge_chain_mutex); if (previous) list_add(&bridge->chain_node, &previous->chain_node); else list_add(&bridge->chain_node, &encoder->bridge_chain); + mutex_unlock(&encoder->bridge_chain_mutex); if (bridge->funcs->attach) { ret = bridge->funcs->attach(bridge, encoder, flags); @@ -496,7 +498,9 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge, err_reset_bridge: bridge->dev = NULL; bridge->encoder = NULL; + mutex_lock(&encoder->bridge_chain_mutex); list_del(&bridge->chain_node); + mutex_unlock(&encoder->bridge_chain_mutex); if (ret != -EPROBE_DEFER) DRM_ERROR("failed to attach bridge %pOF to encoder %s: %d\n", -- 2.51.1
