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drm/vmwgfx: Fix a destoy-while-held mutex problem.

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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>
This commit is contained in:
Thomas Hellstrom 2018-03-21 10:18:38 +01:00
parent 140bcaa23a
commit 73a88250b7
4 changed files with 34 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
View 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);

12
drivers/gpu/drm/vmwgfx/vmwgfx_kms.h
View 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,

5
drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
View 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;
}

5
drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
View 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;
}