]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commitdiff
drm/vmwgfx: Fix a destoy-while-held mutex problem.
authorThomas Hellstrom <thellstrom@vmware.com>
Wed, 21 Mar 2018 09:18:38 +0000 (10:18 +0100)
committerThomas Hellstrom <thellstrom@vmware.com>
Wed, 21 Mar 2018 09:52:01 +0000 (10:52 +0100)
When validating legacy surfaces, the backup bo might be destroyed at
surface validate time. However, the kms resource validation code may have
the bo reserved, so we will destroy a locked mutex. While there shouldn't
be any other users of that mutex when it is destroyed, it causes a lock
leak and thus throws a lockdep error.

Fix this by having the kms resource validation code hold a reference to
the bo while we have it reserved. We do this by introducing a validation
context which might come in handy when the kms code is extended to validate
multiple resources or buffers.

Cc: <stable@vger.kernel.org>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
drivers/gpu/drm/vmwgfx/vmwgfx_kms.h
drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c

index b3d62aa01a9b2e9ad82fd6ccd345436b1954ea99..3c824fd7cbf36d64e72e758bdb7c5b5e3b270dd6 100644 (file)
@@ -31,7 +31,6 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_rect.h>
 
-
 /* Might need a hrtimer here? */
 #define VMWGFX_PRESENT_RATE ((HZ / 60 > 0) ? HZ / 60 : 1)
 
@@ -2517,9 +2516,12 @@ void vmw_kms_helper_buffer_finish(struct vmw_private *dev_priv,
  * Helper to be used if an error forces the caller to undo the actions of
  * vmw_kms_helper_resource_prepare.
  */
-void vmw_kms_helper_resource_revert(struct vmw_resource *res)
+void vmw_kms_helper_resource_revert(struct vmw_validation_ctx *ctx)
 {
-       vmw_kms_helper_buffer_revert(res->backup);
+       struct vmw_resource *res = ctx->res;
+
+       vmw_kms_helper_buffer_revert(ctx->buf);
+       vmw_dmabuf_unreference(&ctx->buf);
        vmw_resource_unreserve(res, false, NULL, 0);
        mutex_unlock(&res->dev_priv->cmdbuf_mutex);
 }
@@ -2536,10 +2538,14 @@ void vmw_kms_helper_resource_revert(struct vmw_resource *res)
  * interrupted by a signal.
  */
 int vmw_kms_helper_resource_prepare(struct vmw_resource *res,
-                                   bool interruptible)
+                                   bool interruptible,
+                                   struct vmw_validation_ctx *ctx)
 {
        int ret = 0;
 
+       ctx->buf = NULL;
+       ctx->res = res;
+
        if (interruptible)
                ret = mutex_lock_interruptible(&res->dev_priv->cmdbuf_mutex);
        else
@@ -2558,6 +2564,8 @@ int vmw_kms_helper_resource_prepare(struct vmw_resource *res,
                                                    res->dev_priv->has_mob);
                if (ret)
                        goto out_unreserve;
+
+               ctx->buf = vmw_dmabuf_reference(res->backup);
        }
        ret = vmw_resource_validate(res);
        if (ret)
@@ -2565,7 +2573,7 @@ int vmw_kms_helper_resource_prepare(struct vmw_resource *res,
        return 0;
 
 out_revert:
-       vmw_kms_helper_buffer_revert(res->backup);
+       vmw_kms_helper_buffer_revert(ctx->buf);
 out_unreserve:
        vmw_resource_unreserve(res, false, NULL, 0);
 out_unlock:
@@ -2581,11 +2589,13 @@ out_unlock:
  * @out_fence: Optional pointer to a fence pointer. If non-NULL, a
  * ref-counted fence pointer is returned here.
  */
-void vmw_kms_helper_resource_finish(struct vmw_resource *res,
-                            struct vmw_fence_obj **out_fence)
+void vmw_kms_helper_resource_finish(struct vmw_validation_ctx *ctx,
+                                   struct vmw_fence_obj **out_fence)
 {
-       if (res->backup || out_fence)
-               vmw_kms_helper_buffer_finish(res->dev_priv, NULL, res->backup,
+       struct vmw_resource *res = ctx->res;
+
+       if (ctx->buf || out_fence)
+               vmw_kms_helper_buffer_finish(res->dev_priv, NULL, ctx->buf,
                                             out_fence, NULL);
 
        vmw_resource_unreserve(res, false, NULL, 0);
index 948362c43c733fdd12b02f8a6683785c40b2e9d6..3d2ca280eaa72ee1a5f8b216bfe7b54467e3d842 100644 (file)
@@ -240,6 +240,11 @@ struct vmw_display_unit {
        int set_gui_y;
 };
 
+struct vmw_validation_ctx {
+       struct vmw_resource *res;
+       struct vmw_dma_buffer *buf;
+};
+
 #define vmw_crtc_to_du(x) \
        container_of(x, struct vmw_display_unit, crtc)
 #define vmw_connector_to_du(x) \
@@ -296,9 +301,10 @@ void vmw_kms_helper_buffer_finish(struct vmw_private *dev_priv,
                                  struct drm_vmw_fence_rep __user *
                                  user_fence_rep);
 int vmw_kms_helper_resource_prepare(struct vmw_resource *res,
-                                   bool interruptible);
-void vmw_kms_helper_resource_revert(struct vmw_resource *res);
-void vmw_kms_helper_resource_finish(struct vmw_resource *res,
+                                   bool interruptible,
+                                   struct vmw_validation_ctx *ctx);
+void vmw_kms_helper_resource_revert(struct vmw_validation_ctx *ctx);
+void vmw_kms_helper_resource_finish(struct vmw_validation_ctx *ctx,
                                    struct vmw_fence_obj **out_fence);
 int vmw_kms_readback(struct vmw_private *dev_priv,
                     struct drm_file *file_priv,
index 63a4cd794b73a12821ea8adbfb72e997367c5193..3ec9eae831b8f15295a6da11a9a267e3e2b4fcb8 100644 (file)
@@ -909,12 +909,13 @@ int vmw_kms_sou_do_surface_dirty(struct vmw_private *dev_priv,
        struct vmw_framebuffer_surface *vfbs =
                container_of(framebuffer, typeof(*vfbs), base);
        struct vmw_kms_sou_surface_dirty sdirty;
+       struct vmw_validation_ctx ctx;
        int ret;
 
        if (!srf)
                srf = &vfbs->surface->res;
 
-       ret = vmw_kms_helper_resource_prepare(srf, true);
+       ret = vmw_kms_helper_resource_prepare(srf, true, &ctx);
        if (ret)
                return ret;
 
@@ -933,7 +934,7 @@ int vmw_kms_sou_do_surface_dirty(struct vmw_private *dev_priv,
        ret = vmw_kms_helper_dirty(dev_priv, framebuffer, clips, vclips,
                                   dest_x, dest_y, num_clips, inc,
                                   &sdirty.base);
-       vmw_kms_helper_resource_finish(srf, out_fence);
+       vmw_kms_helper_resource_finish(&ctx, out_fence);
 
        return ret;
 }
index b68d74888ab1100be82f8a2a9fdc3234a4e04293..6b969e5dea2a862b392153822649217783ac661b 100644 (file)
@@ -980,12 +980,13 @@ int vmw_kms_stdu_surface_dirty(struct vmw_private *dev_priv,
        struct vmw_framebuffer_surface *vfbs =
                container_of(framebuffer, typeof(*vfbs), base);
        struct vmw_stdu_dirty sdirty;
+       struct vmw_validation_ctx ctx;
        int ret;
 
        if (!srf)
                srf = &vfbs->surface->res;
 
-       ret = vmw_kms_helper_resource_prepare(srf, true);
+       ret = vmw_kms_helper_resource_prepare(srf, true, &ctx);
        if (ret)
                return ret;
 
@@ -1008,7 +1009,7 @@ int vmw_kms_stdu_surface_dirty(struct vmw_private *dev_priv,
                                   dest_x, dest_y, num_clips, inc,
                                   &sdirty.base);
 out_finish:
-       vmw_kms_helper_resource_finish(srf, out_fence);
+       vmw_kms_helper_resource_finish(&ctx, out_fence);
 
        return ret;
 }