[PATCH 5/6] drm/i915: Fix lock order reversal with cliprects and cmdbuf in non-DRI2 paths.

From: Eric Anholt
Date: Wed Mar 25 2009 - 17:47:29 EST


This introduces allocation in the batch submission path that wasn't there
previously, but these are compatibility paths so we care about simplicity
more than performance.

kernel.org bug #12419.

Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
Reviewed-by: Keith Packard <keithp@xxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_dma.c | 107 ++++++++++++++++++++++++++------------
drivers/gpu/drm/i915/i915_drv.h | 2 +-
drivers/gpu/drm/i915/i915_gem.c | 27 ++++++++--
3 files changed, 97 insertions(+), 39 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 6d21b9e..ae83fe0 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -356,7 +356,7 @@ static int validate_cmd(int cmd)
return ret;
}

-static int i915_emit_cmds(struct drm_device * dev, int __user * buffer, int dwords)
+static int i915_emit_cmds(struct drm_device * dev, int *buffer, int dwords)
{
drm_i915_private_t *dev_priv = dev->dev_private;
int i;
@@ -370,8 +370,7 @@ static int i915_emit_cmds(struct drm_device * dev, int __user * buffer, int dwor
for (i = 0; i < dwords;) {
int cmd, sz;

- if (DRM_COPY_FROM_USER_UNCHECKED(&cmd, &buffer[i], sizeof(cmd)))
- return -EINVAL;
+ cmd = buffer[i];

if ((sz = validate_cmd(cmd)) == 0 || i + sz > dwords)
return -EINVAL;
@@ -379,11 +378,7 @@ static int i915_emit_cmds(struct drm_device * dev, int __user * buffer, int dwor
OUT_RING(cmd);

while (++i, --sz) {
- if (DRM_COPY_FROM_USER_UNCHECKED(&cmd, &buffer[i],
- sizeof(cmd))) {
- return -EINVAL;
- }
- OUT_RING(cmd);
+ OUT_RING(buffer[i]);
}
}

@@ -397,17 +392,13 @@ static int i915_emit_cmds(struct drm_device * dev, int __user * buffer, int dwor

int
i915_emit_box(struct drm_device *dev,
- struct drm_clip_rect __user *boxes,
+ struct drm_clip_rect *boxes,
int i, int DR1, int DR4)
{
drm_i915_private_t *dev_priv = dev->dev_private;
- struct drm_clip_rect box;
+ struct drm_clip_rect box = boxes[i];
RING_LOCALS;

- if (DRM_COPY_FROM_USER_UNCHECKED(&box, &boxes[i], sizeof(box))) {
- return -EFAULT;
- }
-
if (box.y2 <= box.y1 || box.x2 <= box.x1 || box.y2 <= 0 || box.x2 <= 0) {
DRM_ERROR("Bad box %d,%d..%d,%d\n",
box.x1, box.y1, box.x2, box.y2);
@@ -460,7 +451,9 @@ static void i915_emit_breadcrumb(struct drm_device *dev)
}

static int i915_dispatch_cmdbuffer(struct drm_device * dev,
- drm_i915_cmdbuffer_t * cmd)
+ drm_i915_cmdbuffer_t *cmd,
+ struct drm_clip_rect *cliprects,
+ void *cmdbuf)
{
int nbox = cmd->num_cliprects;
int i = 0, count, ret;
@@ -476,13 +469,13 @@ static int i915_dispatch_cmdbuffer(struct drm_device * dev,

for (i = 0; i < count; i++) {
if (i < nbox) {
- ret = i915_emit_box(dev, cmd->cliprects, i,
+ ret = i915_emit_box(dev, cliprects, i,
cmd->DR1, cmd->DR4);
if (ret)
return ret;
}

- ret = i915_emit_cmds(dev, (int __user *)cmd->buf, cmd->sz / 4);
+ ret = i915_emit_cmds(dev, cmdbuf, cmd->sz / 4);
if (ret)
return ret;
}
@@ -492,10 +485,10 @@ static int i915_dispatch_cmdbuffer(struct drm_device * dev,
}

static int i915_dispatch_batchbuffer(struct drm_device * dev,
- drm_i915_batchbuffer_t * batch)
+ drm_i915_batchbuffer_t * batch,
+ struct drm_clip_rect *cliprects)
{
drm_i915_private_t *dev_priv = dev->dev_private;
- struct drm_clip_rect __user *boxes = batch->cliprects;
int nbox = batch->num_cliprects;
int i = 0, count;
RING_LOCALS;
@@ -511,7 +504,7 @@ static int i915_dispatch_batchbuffer(struct drm_device * dev,

for (i = 0; i < count; i++) {
if (i < nbox) {
- int ret = i915_emit_box(dev, boxes, i,
+ int ret = i915_emit_box(dev, cliprects, i,
batch->DR1, batch->DR4);
if (ret)
return ret;
@@ -626,6 +619,7 @@ static int i915_batchbuffer(struct drm_device *dev, void *data,
master_priv->sarea_priv;
drm_i915_batchbuffer_t *batch = data;
int ret;
+ struct drm_clip_rect *cliprects = NULL;

if (!dev_priv->allow_batchbuffer) {
DRM_ERROR("Batchbuffer ioctl disabled\n");
@@ -637,17 +631,35 @@ static int i915_batchbuffer(struct drm_device *dev, void *data,

RING_LOCK_TEST_WITH_RETURN(dev, file_priv);

- if (batch->num_cliprects && DRM_VERIFYAREA_READ(batch->cliprects,
- batch->num_cliprects *
- sizeof(struct drm_clip_rect)))
- return -EFAULT;
+ if (batch->num_cliprects < 0)
+ return -EINVAL;
+
+ if (batch->num_cliprects) {
+ cliprects = drm_calloc(batch->num_cliprects,
+ sizeof(struct drm_clip_rect),
+ DRM_MEM_DRIVER);
+ if (cliprects == NULL)
+ return -ENOMEM;
+
+ ret = copy_from_user(cliprects, batch->cliprects,
+ batch->num_cliprects *
+ sizeof(struct drm_clip_rect));
+ if (ret != 0)
+ goto fail_free;
+ }

mutex_lock(&dev->struct_mutex);
- ret = i915_dispatch_batchbuffer(dev, batch);
+ ret = i915_dispatch_batchbuffer(dev, batch, cliprects);
mutex_unlock(&dev->struct_mutex);

if (sarea_priv)
sarea_priv->last_dispatch = READ_BREADCRUMB(dev_priv);
+
+fail_free:
+ drm_free(cliprects,
+ batch->num_cliprects * sizeof(struct drm_clip_rect),
+ DRM_MEM_DRIVER);
+
return ret;
}

@@ -659,6 +671,8 @@ static int i915_cmdbuffer(struct drm_device *dev, void *data,
drm_i915_sarea_t *sarea_priv = (drm_i915_sarea_t *)
master_priv->sarea_priv;
drm_i915_cmdbuffer_t *cmdbuf = data;
+ struct drm_clip_rect *cliprects = NULL;
+ void *batch_data;
int ret;

DRM_DEBUG("i915 cmdbuffer, buf %p sz %d cliprects %d\n",
@@ -666,25 +680,50 @@ static int i915_cmdbuffer(struct drm_device *dev, void *data,

RING_LOCK_TEST_WITH_RETURN(dev, file_priv);

- if (cmdbuf->num_cliprects &&
- DRM_VERIFYAREA_READ(cmdbuf->cliprects,
- cmdbuf->num_cliprects *
- sizeof(struct drm_clip_rect))) {
- DRM_ERROR("Fault accessing cliprects\n");
- return -EFAULT;
+ if (cmdbuf->num_cliprects < 0)
+ return -EINVAL;
+
+ batch_data = drm_alloc(cmdbuf->sz, DRM_MEM_DRIVER);
+ if (batch_data == NULL)
+ return -ENOMEM;
+
+ ret = copy_from_user(batch_data, cmdbuf->buf, cmdbuf->sz);
+ if (ret != 0)
+ goto fail_batch_free;
+
+ if (cmdbuf->num_cliprects) {
+ cliprects = drm_calloc(cmdbuf->num_cliprects,
+ sizeof(struct drm_clip_rect),
+ DRM_MEM_DRIVER);
+ if (cliprects == NULL)
+ goto fail_batch_free;
+
+ ret = copy_from_user(cliprects, cmdbuf->cliprects,
+ cmdbuf->num_cliprects *
+ sizeof(struct drm_clip_rect));
+ if (ret != 0)
+ goto fail_clip_free;
}

mutex_lock(&dev->struct_mutex);
- ret = i915_dispatch_cmdbuffer(dev, cmdbuf);
+ ret = i915_dispatch_cmdbuffer(dev, cmdbuf, cliprects, batch_data);
mutex_unlock(&dev->struct_mutex);
if (ret) {
DRM_ERROR("i915_dispatch_cmdbuffer failed\n");
- return ret;
+ goto fail_batch_free;
}

if (sarea_priv)
sarea_priv->last_dispatch = READ_BREADCRUMB(dev_priv);
- return 0;
+
+fail_batch_free:
+ drm_free(batch_data, cmdbuf->sz, DRM_MEM_DRIVER);
+fail_clip_free:
+ drm_free(cliprects,
+ cmdbuf->num_cliprects * sizeof(struct drm_clip_rect),
+ DRM_MEM_DRIVER);
+
+ return ret;
}

static int i915_flip_bufs(struct drm_device *dev, void *data,
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 75e3384..2c02ce6 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -520,7 +520,7 @@ extern int i915_driver_device_is_agp(struct drm_device * dev);
extern long i915_compat_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg);
extern int i915_emit_box(struct drm_device *dev,
- struct drm_clip_rect __user *boxes,
+ struct drm_clip_rect *boxes,
int i, int DR1, int DR4);

/* i915_irq.c */
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 010af90..2bda151 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2891,11 +2891,10 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
static int
i915_dispatch_gem_execbuffer(struct drm_device *dev,
struct drm_i915_gem_execbuffer *exec,
+ struct drm_clip_rect *cliprects,
uint64_t exec_offset)
{
drm_i915_private_t *dev_priv = dev->dev_private;
- struct drm_clip_rect __user *boxes = (struct drm_clip_rect __user *)
- (uintptr_t) exec->cliprects_ptr;
int nbox = exec->num_cliprects;
int i = 0, count;
uint32_t exec_start, exec_len;
@@ -2916,7 +2915,7 @@ i915_dispatch_gem_execbuffer(struct drm_device *dev,

for (i = 0; i < count; i++) {
if (i < nbox) {
- int ret = i915_emit_box(dev, boxes, i,
+ int ret = i915_emit_box(dev, cliprects, i,
exec->DR1, exec->DR4);
if (ret)
return ret;
@@ -2983,6 +2982,7 @@ i915_gem_execbuffer(struct drm_device *dev, void *data,
struct drm_gem_object **object_list = NULL;
struct drm_gem_object *batch_obj;
struct drm_i915_gem_object *obj_priv;
+ struct drm_clip_rect *cliprects = NULL;
int ret, i, pinned = 0;
uint64_t exec_offset;
uint32_t seqno, flush_domains;
@@ -3019,6 +3019,23 @@ i915_gem_execbuffer(struct drm_device *dev, void *data,
goto pre_mutex_err;
}

+ if (args->num_cliprects != 0) {
+ cliprects = drm_calloc(args->num_cliprects, sizeof(*cliprects),
+ DRM_MEM_DRIVER);
+ if (cliprects == NULL)
+ goto pre_mutex_err;
+
+ ret = copy_from_user(cliprects,
+ (struct drm_clip_rect __user *)
+ (uintptr_t) args->cliprects_ptr,
+ sizeof(*cliprects) * args->num_cliprects);
+ if (ret != 0) {
+ DRM_ERROR("copy %d cliprects failed: %d\n",
+ args->num_cliprects, ret);
+ goto pre_mutex_err;
+ }
+ }
+
mutex_lock(&dev->struct_mutex);

i915_verify_inactive(dev, __FILE__, __LINE__);
@@ -3155,7 +3172,7 @@ i915_gem_execbuffer(struct drm_device *dev, void *data,
#endif

/* Exec the batchbuffer */
- ret = i915_dispatch_gem_execbuffer(dev, args, exec_offset);
+ ret = i915_dispatch_gem_execbuffer(dev, args, cliprects, exec_offset);
if (ret) {
DRM_ERROR("dispatch failed %d\n", ret);
goto err;
@@ -3224,6 +3241,8 @@ pre_mutex_err:
DRM_MEM_DRIVER);
drm_free(exec_list, sizeof(*exec_list) * args->buffer_count,
DRM_MEM_DRIVER);
+ drm_free(cliprects, sizeof(*cliprects) * args->num_cliprects,
+ DRM_MEM_DRIVER);

return ret;
}
--
1.6.2.1

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