[PATCH 1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

[PATCH 1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

[Joonas Lahtinen]

Make sure the underlying VMA in the process address space is the
same as it was during vm_mmap to avoid applying WC to wrong VMA.

A more long-term solution would be to have vm_mmap_locked variant
in linux/mmap.h for when caller wants to hold mmap_sem for an
extended duration.

Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")
Reported-by: Adam Zabrocki <adamza@microsoft.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <stable@vger.kernel.org> # v4.0+
Cc: Akash Goel <akash.goel@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Adam Zabrocki <adamza@microsoft.com>
---
 drivers/gpu/drm/i915/i915_gem.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 062c8395557c..f1d594a53978 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1680,6 +1680,15 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data,
 	return 0;
 }
 
+static inline bool
+match_gem_vma(struct vm_area_struct *vma, struct file *filp,
+	      unsigned long addr, unsigned long size)
+{
+	return vma && vma->vm_file == filp &&
+	       vma->vm_start == addr &&
+	       (vma->vm_end - vma->vm_start) == size;
+}
+
 /**
  * i915_gem_mmap_ioctl - Maps the contents of an object, returning the address
  *			 it is mapped to.
@@ -1738,7 +1747,7 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
 			return -EINTR;
 		}
 		vma = find_vma(mm, addr);
-		if (vma)
+		if (match_gem_vma(vma, obj->base.filp, addr, args->size))
 			vma->vm_page_prot =
 				pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
 		else
-- 
2.17.2

[PATCH 1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

[Joonas Lahtinen]

Make sure the underlying VMA in the process address space is the
same as it was during vm_mmap to avoid applying WC to wrong VMA.

A more long-term solution would be to have vm_mmap_locked variant
in linux/mmap.h for when caller wants to hold mmap_sem for an
extended duration.

Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")
Reported-by: Adam Zabrocki <adamza@microsoft.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <stable@vger.kernel.org> # v4.0+
Cc: Akash Goel <akash.goel@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Adam Zabrocki <adamza@microsoft.com>
---
 drivers/gpu/drm/i915/i915_gem.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 062c8395557c..f1d594a53978 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1680,6 +1680,15 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data,
 	return 0;
 }
 
+static inline bool
+match_gem_vma(struct vm_area_struct *vma, struct file *filp,
+	      unsigned long addr, unsigned long size)
+{
+	return vma && vma->vm_file == filp &&
+	       vma->vm_start == addr &&
+	       (vma->vm_end - vma->vm_start) == size;
+}
+
 /**
  * i915_gem_mmap_ioctl - Maps the contents of an object, returning the address
  *			 it is mapped to.
@@ -1738,7 +1747,7 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
 			return -EINTR;
 		}
 		vma = find_vma(mm, addr);
-		if (vma)
+		if (match_gem_vma(vma, obj->base.filp, addr, args->size))
 			vma->vm_page_prot =
 				pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
 		else
-- 
2.17.2

[PATCH 2/2] drm/i915: Handle vm_mmap error during I915_GEM_MMAP ioctl with WC set

[Joonas Lahtinen]

Add err goto label and use it when VMA can't be established or changes
underneath.

Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")
Reported-by: Adam Zabrocki <adamza@microsoft.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <stable@vger.kernel.org> # v4.0+
Cc: Akash Goel <akash.goel@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Adam Zabrocki <adamza@microsoft.com>
---
 drivers/gpu/drm/i915/i915_gem.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index f1d594a53978..97cbc0e27e3e 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1738,6 +1738,9 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
 	addr = vm_mmap(obj->base.filp, 0, args->size,
 		       PROT_READ | PROT_WRITE, MAP_SHARED,
 		       args->offset);
+	if (IS_ERR((void *)addr))
+		goto err;
+
 	if (args->flags & I915_MMAP_WC) {
 		struct mm_struct *mm = current->mm;
 		struct vm_area_struct *vma;
@@ -1753,17 +1756,22 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
 		else
 			addr = -ENOMEM;
 		up_write(&mm->mmap_sem);
+		if (IS_ERR((void *)addr))
+			goto err;
 
 		/* This may race, but that's ok, it only gets set */
 		WRITE_ONCE(obj->frontbuffer_ggtt_origin, ORIGIN_CPU);
 	}
 	i915_gem_object_put(obj);
-	if (IS_ERR((void *)addr))
-		return addr;
 
 	args->addr_ptr = (uint64_t) addr;
 
 	return 0;
+
+err:
+	i915_gem_object_put(obj);
+
+	return addr;
 }
 
 static unsigned int tile_row_pages(const struct drm_i915_gem_object *obj)
-- 
2.17.2

[PATCH 2/2] drm/i915: Handle vm_mmap error during I915_GEM_MMAP ioctl with WC set

[Joonas Lahtinen]

Add err goto label and use it when VMA can't be established or changes
underneath.

Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")
Reported-by: Adam Zabrocki <adamza@microsoft.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <stable@vger.kernel.org> # v4.0+
Cc: Akash Goel <akash.goel@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Adam Zabrocki <adamza@microsoft.com>
---
 drivers/gpu/drm/i915/i915_gem.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index f1d594a53978..97cbc0e27e3e 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1738,6 +1738,9 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
 	addr = vm_mmap(obj->base.filp, 0, args->size,
 		       PROT_READ | PROT_WRITE, MAP_SHARED,
 		       args->offset);
+	if (IS_ERR((void *)addr))
+		goto err;
+
 	if (args->flags & I915_MMAP_WC) {
 		struct mm_struct *mm = current->mm;
 		struct vm_area_struct *vma;
@@ -1753,17 +1756,22 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
 		else
 			addr = -ENOMEM;
 		up_write(&mm->mmap_sem);
+		if (IS_ERR((void *)addr))
+			goto err;
 
 		/* This may race, but that's ok, it only gets set */
 		WRITE_ONCE(obj->frontbuffer_ggtt_origin, ORIGIN_CPU);
 	}
 	i915_gem_object_put(obj);
-	if (IS_ERR((void *)addr))
-		return addr;
 
 	args->addr_ptr = (uint64_t) addr;
 
 	return 0;
+
+err:
+	i915_gem_object_put(obj);
+
+	return addr;
 }
 
 static unsigned int tile_row_pages(const struct drm_i915_gem_object *obj)
-- 
2.17.2

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Re: [PATCH 2/2] drm/i915: Handle vm_mmap error during I915_GEM_MMAP ioctl with WC set

[Chris Wilson]

Quoting Joonas Lahtinen (2019-01-07 08:56:56)
> Add err goto label and use it when VMA can't be established or changes
> underneath.
> 
> Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")

Dubious. All it changes is one branch where the error is forced to
-ENOMEM.

> Reported-by: Adam Zabrocki <adamza@microsoft.com>
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v4.0+
> Cc: Akash Goel <akash.goel@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: Adam Zabrocki <adamza@microsoft.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index f1d594a53978..97cbc0e27e3e 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1738,6 +1738,9 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>         addr = vm_mmap(obj->base.filp, 0, args->size,
>                        PROT_READ | PROT_WRITE, MAP_SHARED,
>                        args->offset);
> +       if (IS_ERR((void *)addr))
> +               goto err;
> +
>         if (args->flags & I915_MMAP_WC) {
>                 struct mm_struct *mm = current->mm;
>                 struct vm_area_struct *vma;
> @@ -1753,17 +1756,22 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>                 else
>                         addr = -ENOMEM;
>                 up_write(&mm->mmap_sem);
> +               if (IS_ERR((void *)addr))
> +                       goto err;

The issue still remains that we are returning having called vm_mmap and
leaving the vma intact. And we've established above that calling
vm_munmap() is a race.
-Chris

Re: [PATCH 2/2] drm/i915: Handle vm_mmap error during I915_GEM_MMAP ioctl with WC set

[Chris Wilson]

Quoting Joonas Lahtinen (2019-01-07 08:56:56)
> Add err goto label and use it when VMA can't be established or changes
> underneath.
> 
> Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")

Dubious. All it changes is one branch where the error is forced to
-ENOMEM.

> Reported-by: Adam Zabrocki <adamza@microsoft.com>
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v4.0+
> Cc: Akash Goel <akash.goel@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: Adam Zabrocki <adamza@microsoft.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index f1d594a53978..97cbc0e27e3e 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1738,6 +1738,9 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>         addr = vm_mmap(obj->base.filp, 0, args->size,
>                        PROT_READ | PROT_WRITE, MAP_SHARED,
>                        args->offset);
> +       if (IS_ERR((void *)addr))
> +               goto err;
> +
>         if (args->flags & I915_MMAP_WC) {
>                 struct mm_struct *mm = current->mm;
>                 struct vm_area_struct *vma;
> @@ -1753,17 +1756,22 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>                 else
>                         addr = -ENOMEM;
>                 up_write(&mm->mmap_sem);
> +               if (IS_ERR((void *)addr))
> +                       goto err;

The issue still remains that we are returning having called vm_mmap and
leaving the vma intact. And we've established above that calling
vm_munmap() is a race.
-Chris

Re: [PATCH 2/2] drm/i915: Handle vm_mmap error during I915_GEM_MMAP ioctl with WC set

[Tvrtko Ursulin]

On 07/01/2019 08:56, Joonas Lahtinen wrote:
> Add err goto label and use it when VMA can't be established or changes
> underneath.
> 
> Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")
> Reported-by: Adam Zabrocki <adamza@microsoft.com>
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v4.0+
> Cc: Akash Goel <akash.goel@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: Adam Zabrocki <adamza@microsoft.com>
> ---
>   drivers/gpu/drm/i915/i915_gem.c | 12 ++++++++++--
>   1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index f1d594a53978..97cbc0e27e3e 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1738,6 +1738,9 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>   	addr = vm_mmap(obj->base.filp, 0, args->size,
>   		       PROT_READ | PROT_WRITE, MAP_SHARED,
>   		       args->offset);
> +	if (IS_ERR((void *)addr))
> +		goto err;
> +
>   	if (args->flags & I915_MMAP_WC) {
>   		struct mm_struct *mm = current->mm;
>   		struct vm_area_struct *vma;
> @@ -1753,17 +1756,22 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>   		else
>   			addr = -ENOMEM;
>   		up_write(&mm->mmap_sem);
> +		if (IS_ERR((void *)addr))
> +			goto err;
>   
>   		/* This may race, but that's ok, it only gets set */
>   		WRITE_ONCE(obj->frontbuffer_ggtt_origin, ORIGIN_CPU);
>   	}
>   	i915_gem_object_put(obj);
> -	if (IS_ERR((void *)addr))
> -		return addr;
>   
>   	args->addr_ptr = (uint64_t) addr;
>   
>   	return 0;
> +
> +err:
> +	i915_gem_object_put(obj);
> +
> +	return addr;
>   }
>   
>   static unsigned int tile_row_pages(const struct drm_i915_gem_object *obj)
> 

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Regards,

Tvrtko

Re: [PATCH 2/2] drm/i915: Handle vm_mmap error during I915_GEM_MMAP ioctl with WC set

[Tvrtko Ursulin]

On 07/01/2019 08:56, Joonas Lahtinen wrote:
> Add err goto label and use it when VMA can't be established or changes
> underneath.
> 
> Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")
> Reported-by: Adam Zabrocki <adamza@microsoft.com>
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v4.0+
> Cc: Akash Goel <akash.goel@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: Adam Zabrocki <adamza@microsoft.com>
> ---
>   drivers/gpu/drm/i915/i915_gem.c | 12 ++++++++++--
>   1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index f1d594a53978..97cbc0e27e3e 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1738,6 +1738,9 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>   	addr = vm_mmap(obj->base.filp, 0, args->size,
>   		       PROT_READ | PROT_WRITE, MAP_SHARED,
>   		       args->offset);
> +	if (IS_ERR((void *)addr))
> +		goto err;
> +
>   	if (args->flags & I915_MMAP_WC) {
>   		struct mm_struct *mm = current->mm;
>   		struct vm_area_struct *vma;
> @@ -1753,17 +1756,22 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>   		else
>   			addr = -ENOMEM;
>   		up_write(&mm->mmap_sem);
> +		if (IS_ERR((void *)addr))
> +			goto err;
>   
>   		/* This may race, but that's ok, it only gets set */
>   		WRITE_ONCE(obj->frontbuffer_ggtt_origin, ORIGIN_CPU);
>   	}
>   	i915_gem_object_put(obj);
> -	if (IS_ERR((void *)addr))
> -		return addr;
>   
>   	args->addr_ptr = (uint64_t) addr;
>   
>   	return 0;
> +
> +err:
> +	i915_gem_object_put(obj);
> +
> +	return addr;
>   }
>   
>   static unsigned int tile_row_pages(const struct drm_i915_gem_object *obj)
> 

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Regards,

Tvrtko

Re: [PATCH 1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

[Chris Wilson]

Quoting Joonas Lahtinen (2019-01-07 08:56:55)
> Make sure the underlying VMA in the process address space is the
> same as it was during vm_mmap to avoid applying WC to wrong VMA.
> 
> A more long-term solution would be to have vm_mmap_locked variant
> in linux/mmap.h for when caller wants to hold mmap_sem for an
> extended duration.
> 
> Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")
> Reported-by: Adam Zabrocki <adamza@microsoft.com>
> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v4.0+
> Cc: Akash Goel <akash.goel@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: Adam Zabrocki <adamza@microsoft.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 062c8395557c..f1d594a53978 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1680,6 +1680,15 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data,
>         return 0;
>  }
>  
> +static inline bool
> +match_gem_vma(struct vm_area_struct *vma, struct file *filp,
> +             unsigned long addr, unsigned long size)

With the exception of there isn't anything gem specific here,

> +{
> +       return vma && vma->vm_file == filp &&
> +              vma->vm_start == addr &&
> +              (vma->vm_end - vma->vm_start) == size;

and we can break this up into separate ifs with a forgiving compiler,

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

I still couldn't see an easy way of passing pgprot bits into do_mmap to
avoid the race entirely.
-Chris

Re: [PATCH 1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

[Chris Wilson]

Quoting Joonas Lahtinen (2019-01-07 08:56:55)
> Make sure the underlying VMA in the process address space is the
> same as it was during vm_mmap to avoid applying WC to wrong VMA.
> 
> A more long-term solution would be to have vm_mmap_locked variant
> in linux/mmap.h for when caller wants to hold mmap_sem for an
> extended duration.
> 
> Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")
> Reported-by: Adam Zabrocki <adamza@microsoft.com>
> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v4.0+
> Cc: Akash Goel <akash.goel@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: Adam Zabrocki <adamza@microsoft.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 062c8395557c..f1d594a53978 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1680,6 +1680,15 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data,
>         return 0;
>  }
>  
> +static inline bool
> +match_gem_vma(struct vm_area_struct *vma, struct file *filp,
> +             unsigned long addr, unsigned long size)

With the exception of there isn't anything gem specific here,

> +{
> +       return vma && vma->vm_file == filp &&
> +              vma->vm_start == addr &&
> +              (vma->vm_end - vma->vm_start) == size;

and we can break this up into separate ifs with a forgiving compiler,

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

I still couldn't see an easy way of passing pgprot bits into do_mmap to
avoid the race entirely.
-Chris

Re: [PATCH 1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

[Tvrtko Ursulin]

On 07/01/2019 08:56, Joonas Lahtinen wrote:
> Make sure the underlying VMA in the process address space is the
> same as it was during vm_mmap to avoid applying WC to wrong VMA.
> 
> A more long-term solution would be to have vm_mmap_locked variant
> in linux/mmap.h for when caller wants to hold mmap_sem for an
> extended duration.
> 
> Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")
> Reported-by: Adam Zabrocki <adamza@microsoft.com>
> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v4.0+
> Cc: Akash Goel <akash.goel@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: Adam Zabrocki <adamza@microsoft.com>
> ---
>   drivers/gpu/drm/i915/i915_gem.c | 11 ++++++++++-
>   1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 062c8395557c..f1d594a53978 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1680,6 +1680,15 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data,
>   	return 0;
>   }
>   
> +static inline bool
> +match_gem_vma(struct vm_area_struct *vma, struct file *filp,
> +	      unsigned long addr, unsigned long size)
> +{
> +	return vma && vma->vm_file == filp &&
> +	       vma->vm_start == addr &&
> +	       (vma->vm_end - vma->vm_start) == size;
> +}
> +
>   /**
>    * i915_gem_mmap_ioctl - Maps the contents of an object, returning the address
>    *			 it is mapped to.
> @@ -1738,7 +1747,7 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>   			return -EINTR;
>   		}
>   		vma = find_vma(mm, addr);
> -		if (vma)
> +		if (match_gem_vma(vma, obj->base.filp, addr, args->size))
>   			vma->vm_page_prot =
>   				pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
>   		else
> 

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Regards,

Tvrtko

Re: [PATCH 1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

[Tvrtko Ursulin]

On 07/01/2019 08:56, Joonas Lahtinen wrote:
> Make sure the underlying VMA in the process address space is the
> same as it was during vm_mmap to avoid applying WC to wrong VMA.
> 
> A more long-term solution would be to have vm_mmap_locked variant
> in linux/mmap.h for when caller wants to hold mmap_sem for an
> extended duration.
> 
> Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")
> Reported-by: Adam Zabrocki <adamza@microsoft.com>
> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v4.0+
> Cc: Akash Goel <akash.goel@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: Adam Zabrocki <adamza@microsoft.com>
> ---
>   drivers/gpu/drm/i915/i915_gem.c | 11 ++++++++++-
>   1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 062c8395557c..f1d594a53978 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1680,6 +1680,15 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data,
>   	return 0;
>   }
>   
> +static inline bool
> +match_gem_vma(struct vm_area_struct *vma, struct file *filp,
> +	      unsigned long addr, unsigned long size)
> +{
> +	return vma && vma->vm_file == filp &&
> +	       vma->vm_start == addr &&
> +	       (vma->vm_end - vma->vm_start) == size;
> +}
> +
>   /**
>    * i915_gem_mmap_ioctl - Maps the contents of an object, returning the address
>    *			 it is mapped to.
> @@ -1738,7 +1747,7 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>   			return -EINTR;
>   		}
>   		vma = find_vma(mm, addr);
> -		if (vma)
> +		if (match_gem_vma(vma, obj->base.filp, addr, args->size))
>   			vma->vm_page_prot =
>   				pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
>   		else
> 

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Regards,

Tvrtko

✓ Fi.CI.BAT: success for series starting with [1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

[Patchwork]

== Series Details ==

Series: series starting with [1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set
URL   : https://patchwork.freedesktop.org/series/54797/
State : success

== Summary ==

CI Bug Log - changes from CI_DRM_5364 -> Patchwork_11198
====================================================

Summary
-------

  **SUCCESS**

  No regressions found.

  External URL: https://patchwork.freedesktop.org/api/1.0/series/54797/revisions/1/mbox/

Known issues
------------

  Here are the changes found in Patchwork_11198 that come from known issues:

### IGT changes ###

#### Issues hit ####

  * igt@amdgpu/amd_basic@cs-compute:
    - fi-kbl-8809g:       NOTRUN -> FAIL [fdo#108094]

  * igt@amdgpu/amd_prime@amd-to-i915:
    - fi-kbl-8809g:       NOTRUN -> FAIL [fdo#107341]

  * igt@gem_exec_suspend@basic-s4-devices:
    - fi-blb-e6850:       PASS -> INCOMPLETE [fdo#107718]

  * igt@i915_selftest@live_evict:
    - fi-bsw-kefka:       PASS -> DMESG-WARN [fdo#107709]

  * igt@pm_rpm@module-reload:
    - fi-icl-u2:          PASS -> DMESG-WARN [fdo#108654]

  
#### Possible fixes ####

  * igt@amdgpu/amd_basic@userptr:
    - fi-kbl-8809g:       DMESG-WARN [fdo#108965] -> PASS

  * igt@kms_chamelium@hdmi-hpd-fast:
    - fi-kbl-7500u:       FAIL [fdo#108767] -> PASS

  * igt@kms_frontbuffer_tracking@basic:
    - fi-byt-clapper:     FAIL [fdo#103167] -> PASS

  * igt@kms_pipe_crc_basic@hang-read-crc-pipe-a:
    - fi-byt-clapper:     FAIL [fdo#103191] / [fdo#107362] -> PASS

  
  {name}: This element is suppressed. This means it is ignored when computing
          the status of the difference (SUCCESS, WARNING, or FAILURE).

  [fdo#103167]: https://bugs.freedesktop.org/show_bug.cgi?id=103167
  [fdo#103191]: https://bugs.freedesktop.org/show_bug.cgi?id=103191
  [fdo#107341]: https://bugs.freedesktop.org/show_bug.cgi?id=107341
  [fdo#107362]: https://bugs.freedesktop.org/show_bug.cgi?id=107362
  [fdo#107709]: https://bugs.freedesktop.org/show_bug.cgi?id=107709
  [fdo#107718]: https://bugs.freedesktop.org/show_bug.cgi?id=107718
  [fdo#108094]: https://bugs.freedesktop.org/show_bug.cgi?id=108094
  [fdo#108654]: https://bugs.freedesktop.org/show_bug.cgi?id=108654
  [fdo#108767]: https://bugs.freedesktop.org/show_bug.cgi?id=108767
  [fdo#108965]: https://bugs.freedesktop.org/show_bug.cgi?id=108965


Participating hosts (43 -> 39)
------------------------------

  Additional (1): fi-kbl-7560u 
  Missing    (5): fi-ilk-m540 fi-hsw-4200u fi-byt-squawks fi-bsw-cyan fi-glk-j4005 


Build changes
-------------

    * Linux: CI_DRM_5364 -> Patchwork_11198

  CI_DRM_5364: 53364c9f70e33458fe848372778f8d0eba994f91 @ git://anongit.freedesktop.org/gfx-ci/linux
  IGT_4756: 75081c6bfb9998bd7cbf35a7ac0578c683fe55a8 @ git://anongit.freedesktop.org/xorg/app/intel-gpu-tools
  Patchwork_11198: e6454c963d6c544b9395ffe92a8ac443f8e6080f @ git://anongit.freedesktop.org/gfx-ci/linux


== Linux commits ==

e6454c963d6c drm/i915: Handle vm_mmap error during I915_GEM_MMAP ioctl with WC set
877d1741097f drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

== Logs ==

For more details see: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_11198/
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

✗ Fi.CI.IGT: failure for series starting with [1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

[Patchwork]

== Series Details ==

Series: series starting with [1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set
URL   : https://patchwork.freedesktop.org/series/54797/
State : failure

== Summary ==

CI Bug Log - changes from CI_DRM_5364_full -> Patchwork_11198_full
====================================================

Summary
-------

  **FAILURE**

  Serious unknown changes coming with Patchwork_11198_full absolutely need to be
  verified manually.
  
  If you think the reported changes have nothing to do with the changes
  introduced in Patchwork_11198_full, please notify your bug team to allow them
  to document this new failure mode, which will reduce false positives in CI.

  

Possible new issues
-------------------

  Here are the unknown changes that may have been introduced in Patchwork_11198_full:

### IGT changes ###

#### Possible regressions ####

  * igt@gem_userptr_blits@readonly-unsync:
    - shard-apl:          PASS -> TIMEOUT

  * igt@kms_draw_crc@draw-method-rgb565-mmap-wc-untiled:
    - shard-apl:          PASS -> FAIL
    - shard-glk:          PASS -> FAIL
    - shard-kbl:          PASS -> FAIL

  
#### Warnings ####

  * igt@kms_ccs@pipe-a-bad-aux-stride:
    - shard-apl:          SKIP -> PASS

  * igt@tools_test@tools_test:
    - shard-glk:          PASS -> SKIP

  
Known issues
------------

  Here are the changes found in Patchwork_11198_full that come from known issues:

### IGT changes ###

#### Issues hit ####

  * igt@kms_atomic_transition@1x-modeset-transitions:
    - shard-skl:          NOTRUN -> FAIL [fdo#107815] / [fdo#108470] +1

  * igt@kms_busy@extended-modeset-hang-newfb-with-reset-render-a:
    - shard-skl:          NOTRUN -> DMESG-WARN [fdo#107956]

  * igt@kms_busy@extended-modeset-hang-newfb-with-reset-render-c:
    - shard-apl:          NOTRUN -> DMESG-WARN [fdo#107956] +1

  * igt@kms_busy@extended-pageflip-hang-newfb-render-c:
    - shard-glk:          PASS -> DMESG-WARN [fdo#107956]

  * igt@kms_busy@extended-pageflip-modeset-hang-oldfb-render-a:
    - shard-iclb:         NOTRUN -> DMESG-WARN [fdo#107956]

  * igt@kms_busy@extended-pageflip-modeset-hang-oldfb-render-c:
    - shard-apl:          PASS -> DMESG-WARN [fdo#107956]

  * igt@kms_chv_cursor_fail@pipe-b-128x128-top-edge:
    - shard-skl:          NOTRUN -> FAIL [fdo#104671]

  * igt@kms_cursor_crc@cursor-128x128-sliding:
    - shard-iclb:         NOTRUN -> FAIL [fdo#103232]

  * igt@kms_cursor_crc@cursor-128x42-sliding:
    - shard-apl:          PASS -> FAIL [fdo#103232]
    - shard-glk:          PASS -> FAIL [fdo#103232]

  * igt@kms_fbcon_fbt@psr:
    - shard-iclb:         NOTRUN -> FAIL [fdo#107882]

  * igt@kms_flip@flip-vs-expired-vblank:
    - shard-skl:          NOTRUN -> FAIL [fdo#105363]

  * igt@kms_frontbuffer_tracking@fbc-1p-primscrn-pri-shrfb-draw-mmap-gtt:
    - shard-skl:          NOTRUN -> FAIL [fdo#103167]

  * igt@kms_frontbuffer_tracking@fbc-1p-primscrn-spr-indfb-move:
    - shard-iclb:         PASS -> FAIL [fdo#103167] +4

  * igt@kms_frontbuffer_tracking@fbc-2p-primscrn-spr-indfb-draw-pwrite:
    - shard-glk:          PASS -> FAIL [fdo#103167]

  * igt@kms_pipe_crc_basic@suspend-read-crc-pipe-b:
    - shard-skl:          NOTRUN -> FAIL [fdo#103191] / [fdo#107362] +1

  * igt@kms_pipe_crc_basic@suspend-read-crc-pipe-c:
    - shard-iclb:         PASS -> INCOMPLETE [fdo#107713]

  * igt@kms_plane@pixel-format-pipe-c-planes-source-clamping:
    - shard-skl:          NOTRUN -> DMESG-WARN [fdo#106885]

  * igt@kms_plane@plane-position-covered-pipe-b-planes:
    - shard-glk:          PASS -> FAIL [fdo#103166] +1

  * igt@kms_plane_alpha_blend@pipe-a-alpha-7efc:
    - shard-skl:          NOTRUN -> FAIL [fdo#107815] / [fdo#108145] +2

  * igt@kms_plane_alpha_blend@pipe-a-constant-alpha-max:
    - shard-skl:          NOTRUN -> FAIL [fdo#108145] +1

  * igt@kms_plane_multiple@atomic-pipe-a-tiling-y:
    - shard-iclb:         PASS -> FAIL [fdo#103166] +1

  * igt@kms_plane_multiple@atomic-pipe-b-tiling-yf:
    - shard-skl:          NOTRUN -> FAIL [fdo#103166] / [fdo#107815]

  * igt@kms_rotation_crc@multiplane-rotation-cropping-top:
    - shard-iclb:         PASS -> DMESG-WARN [fdo#107724]

  * igt@kms_setmode@basic:
    - shard-skl:          NOTRUN -> FAIL [fdo#99912]
    - shard-kbl:          PASS -> FAIL [fdo#99912]

  * igt@kms_vblank@pipe-c-ts-continuation-suspend:
    - shard-skl:          NOTRUN -> INCOMPLETE [fdo#104108] / [fdo#107773]

  * igt@pm_rpm@legacy-planes:
    - shard-iclb:         PASS -> INCOMPLETE [fdo#108840]

  * igt@pm_rps@min-max-config-loaded:
    - shard-glk:          PASS -> FAIL [fdo#102250]

  
#### Possible fixes ####

  * igt@gem_exec_async@concurrent-writes-vebox:
    - shard-skl:          INCOMPLETE -> PASS

  * igt@kms_atomic_transition@plane-all-transition-nonblocking-fencing:
    - shard-apl:          DMESG-WARN [fdo#103558] / [fdo#105602] / [fdo#109225] -> PASS

  * igt@kms_available_modes_crc@available_mode_test_crc:
    - shard-apl:          FAIL [fdo#106641] -> PASS

  * igt@kms_busy@extended-pageflip-modeset-hang-oldfb-render-a:
    - shard-glk:          DMESG-WARN [fdo#107956] -> PASS

  * igt@kms_color@pipe-c-ctm-max:
    - shard-apl:          FAIL [fdo#108147] -> PASS

  * igt@kms_cursor_crc@cursor-256x256-sliding:
    - shard-skl:          FAIL [fdo#103232] -> PASS

  * igt@kms_cursor_crc@cursor-256x256-suspend:
    - shard-apl:          FAIL [fdo#103191] / [fdo#103232] -> PASS

  * igt@kms_cursor_crc@cursor-256x85-onscreen:
    - shard-glk:          FAIL [fdo#103232] -> PASS

  * igt@kms_cursor_crc@cursor-256x85-random:
    - shard-apl:          FAIL [fdo#103232] -> PASS +5

  * igt@kms_cursor_legacy@all-pipes-torture-bo:
    - shard-hsw:          DMESG-WARN [fdo#107122] -> PASS

  * igt@kms_fbcon_fbt@fbc-suspend:
    - shard-iclb:         INCOMPLETE [fdo#107713] -> PASS +1

  * igt@kms_flip@basic-flip-vs-dpms:
    - shard-kbl:          DMESG-WARN [fdo#103313] / [fdo#105345] -> PASS

  * igt@kms_flip@flip-vs-dpms-off-vs-modeset:
    - shard-apl:          DMESG-WARN [fdo#103558] / [fdo#105602] -> PASS +44

  * igt@kms_flip@flip-vs-expired-vblank-interruptible:
    - shard-skl:          FAIL [fdo#105363] -> PASS

  * igt@kms_frontbuffer_tracking@fbc-1p-primscrn-spr-indfb-move:
    - shard-apl:          FAIL [fdo#103167] -> PASS

  * igt@kms_frontbuffer_tracking@fbcpsr-1p-primscrn-spr-indfb-onoff:
    - shard-iclb:         FAIL [fdo#103167] -> PASS +4

  * igt@kms_pipe_crc_basic@nonblocking-crc-pipe-c:
    - shard-skl:          FAIL [fdo#107362] -> PASS

  * igt@kms_plane@plane-position-covered-pipe-b-planes:
    - shard-iclb:         FAIL [fdo#103166] -> PASS

  * igt@kms_plane_alpha_blend@pipe-c-coverage-7efc:
    - shard-skl:          FAIL [fdo#107815] -> PASS

  * igt@kms_plane_multiple@atomic-pipe-a-tiling-y:
    - shard-glk:          FAIL [fdo#103166] -> PASS +1

  * igt@kms_plane_scaling@pipe-b-scaler-with-rotation:
    - shard-iclb:         DMESG-WARN [fdo#107724] -> PASS

  * igt@perf_pmu@rc6-runtime-pm-long:
    - shard-iclb:         FAIL [fdo#105010] -> PASS
    - shard-skl:          FAIL [fdo#105010] -> PASS

  * igt@pm_rpm@reg-read-ioctl:
    - shard-iclb:         INCOMPLETE [fdo#107713] / [fdo#108840] -> PASS

  * igt@pm_rpm@system-suspend-execbuf:
    - shard-apl:          DMESG-WARN [fdo#108131] -> PASS

  
#### Warnings ####

  * igt@i915_suspend@shrink:
    - shard-skl:          INCOMPLETE [fdo#106886] -> DMESG-WARN [fdo#107886] / [fdo#108784]

  * igt@kms_cursor_crc@cursor-128x128-suspend:
    - shard-glk:          FAIL [fdo#103232] -> INCOMPLETE [fdo#103359] / [k.org#198133]

  * igt@kms_plane_alpha_blend@pipe-b-constant-alpha-max:
    - shard-apl:          DMESG-FAIL [fdo#103558] / [fdo#105602] / [fdo#108145] -> FAIL [fdo#108145]

  
  [fdo#102250]: https://bugs.freedesktop.org/show_bug.cgi?id=102250
  [fdo#103166]: https://bugs.freedesktop.org/show_bug.cgi?id=103166
  [fdo#103167]: https://bugs.freedesktop.org/show_bug.cgi?id=103167
  [fdo#103191]: https://bugs.freedesktop.org/show_bug.cgi?id=103191
  [fdo#103232]: https://bugs.freedesktop.org/show_bug.cgi?id=103232
  [fdo#103313]: https://bugs.freedesktop.org/show_bug.cgi?id=103313
  [fdo#103359]: https://bugs.freedesktop.org/show_bug.cgi?id=103359
  [fdo#103558]: https://bugs.freedesktop.org/show_bug.cgi?id=103558
  [fdo#104108]: https://bugs.freedesktop.org/show_bug.cgi?id=104108
  [fdo#104671]: https://bugs.freedesktop.org/show_bug.cgi?id=104671
  [fdo#105010]: https://bugs.freedesktop.org/show_bug.cgi?id=105010
  [fdo#105345]: https://bugs.freedesktop.org/show_bug.cgi?id=105345
  [fdo#105363]: https://bugs.freedesktop.org/show_bug.cgi?id=105363
  [fdo#105602]: https://bugs.freedesktop.org/show_bug.cgi?id=105602
  [fdo#106641]: https://bugs.freedesktop.org/show_bug.cgi?id=106641
  [fdo#106885]: https://bugs.freedesktop.org/show_bug.cgi?id=106885
  [fdo#106886]: https://bugs.freedesktop.org/show_bug.cgi?id=106886
  [fdo#107122]: https://bugs.freedesktop.org/show_bug.cgi?id=107122
  [fdo#107362]: https://bugs.freedesktop.org/show_bug.cgi?id=107362
  [fdo#107713]: https://bugs.freedesktop.org/show_bug.cgi?id=107713
  [fdo#107724]: https://bugs.freedesktop.org/show_bug.cgi?id=107724
  [fdo#107773]: https://bugs.freedesktop.org/show_bug.cgi?id=107773
  [fdo#107815]: https://bugs.freedesktop.org/show_bug.cgi?id=107815
  [fdo#107882]: https://bugs.freedesktop.org/show_bug.cgi?id=107882
  [fdo#107886]: https://bugs.freedesktop.org/show_bug.cgi?id=107886
  [fdo#107956]: https://bugs.freedesktop.org/show_bug.cgi?id=107956
  [fdo#108131]: https://bugs.freedesktop.org/show_bug.cgi?id=108131
  [fdo#108145]: https://bugs.freedesktop.org/show_bug.cgi?id=108145
  [fdo#108147]: https://bugs.freedesktop.org/show_bug.cgi?id=108147
  [fdo#108470]: https://bugs.freedesktop.org/show_bug.cgi?id=108470
  [fdo#108784]: https://bugs.freedesktop.org/show_bug.cgi?id=108784
  [fdo#108840]: https://bugs.freedesktop.org/show_bug.cgi?id=108840
  [fdo#109225]: https://bugs.freedesktop.org/show_bug.cgi?id=109225
  [fdo#99912]: https://bugs.freedesktop.org/show_bug.cgi?id=99912
  [k.org#198133]: https://bugzilla.kernel.org/show_bug.cgi?id=198133


Participating hosts (7 -> 7)
------------------------------

  No changes in participating hosts


Build changes
-------------

    * Linux: CI_DRM_5364 -> Patchwork_11198

  CI_DRM_5364: 53364c9f70e33458fe848372778f8d0eba994f91 @ git://anongit.freedesktop.org/gfx-ci/linux
  IGT_4756: 75081c6bfb9998bd7cbf35a7ac0578c683fe55a8 @ git://anongit.freedesktop.org/xorg/app/intel-gpu-tools
  Patchwork_11198: e6454c963d6c544b9395ffe92a8ac443f8e6080f @ git://anongit.freedesktop.org/gfx-ci/linux
  piglit_4509: fdc5a4ca11124ab8413c7988896eec4c97336694 @ git://anongit.freedesktop.org/piglit

== Logs ==

For more details see: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_11198/
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Re: ✗ Fi.CI.IGT: failure for series starting with [1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

[Chris Wilson]

Quoting Patchwork (2019-01-07 10:44:01)
> ### IGT changes ###
> 
> #### Possible regressions ####
> 
>   * igt@gem_userptr_blits@readonly-unsync:
>     - shard-apl:          PASS -> TIMEOUT
> 
>   * igt@kms_draw_crc@draw-method-rgb565-mmap-wc-untiled:
>     - shard-apl:          PASS -> FAIL
>     - shard-glk:          PASS -> FAIL
>     - shard-kbl:          PASS -> FAIL

igt_fb doesn't compute a page aligned size, and igt_draw ends up making
a mmap request not rounding up to the page boundary. I wonder if that
hasn't been causing a few flip-flips...
-Chris
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Re: [PATCH 1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

[Joonas Lahtinen]

Quoting Joonas Lahtinen (2019-01-07 10:56:55)
> Make sure the underlying VMA in the process address space is the
> same as it was during vm_mmap to avoid applying WC to wrong VMA.
> 
> A more long-term solution would be to have vm_mmap_locked variant
> in linux/mmap.h for when caller wants to hold mmap_sem for an
> extended duration.

These are now merged to drm-tip, and will head to 5.1 and then
to stable kernels.

Thanks for the report and reviews!

Regards, Joonas

> Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")
> Reported-by: Adam Zabrocki <adamza@microsoft.com>
> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v4.0+
> Cc: Akash Goel <akash.goel@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: Adam Zabrocki <adamza@microsoft.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 062c8395557c..f1d594a53978 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1680,6 +1680,15 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data,
>         return 0;
>  }
>  
> +static inline bool
> +match_gem_vma(struct vm_area_struct *vma, struct file *filp,
> +             unsigned long addr, unsigned long size)
> +{
> +       return vma && vma->vm_file == filp &&
> +              vma->vm_start == addr &&
> +              (vma->vm_end - vma->vm_start) == size;
> +}
> +
>  /**
>   * i915_gem_mmap_ioctl - Maps the contents of an object, returning the address
>   *                      it is mapped to.
> @@ -1738,7 +1747,7 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>                         return -EINTR;
>                 }
>                 vma = find_vma(mm, addr);
> -               if (vma)
> +               if (match_gem_vma(vma, obj->base.filp, addr, args->size))
>                         vma->vm_page_prot =
>                                 pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
>                 else
> -- 
> 2.17.2
> 

Re: [PATCH 1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

[Joonas Lahtinen]

Quoting Joonas Lahtinen (2019-01-07 10:56:55)
> Make sure the underlying VMA in the process address space is the
> same as it was during vm_mmap to avoid applying WC to wrong VMA.
> 
> A more long-term solution would be to have vm_mmap_locked variant
> in linux/mmap.h for when caller wants to hold mmap_sem for an
> extended duration.

These are now merged to drm-tip, and will head to 5.1 and then
to stable kernels.

Thanks for the report and reviews!

Regards, Joonas

> Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")
> Reported-by: Adam Zabrocki <adamza@microsoft.com>
> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v4.0+
> Cc: Akash Goel <akash.goel@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: Adam Zabrocki <adamza@microsoft.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 062c8395557c..f1d594a53978 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1680,6 +1680,15 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data,
>         return 0;
>  }
>  
> +static inline bool
> +match_gem_vma(struct vm_area_struct *vma, struct file *filp,
> +             unsigned long addr, unsigned long size)
> +{
> +       return vma && vma->vm_file == filp &&
> +              vma->vm_start == addr &&
> +              (vma->vm_end - vma->vm_start) == size;
> +}
> +
>  /**
>   * i915_gem_mmap_ioctl - Maps the contents of an object, returning the address
>   *                      it is mapped to.
> @@ -1738,7 +1747,7 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>                         return -EINTR;
>                 }
>                 vma = find_vma(mm, addr);
> -               if (vma)
> +               if (match_gem_vma(vma, obj->base.filp, addr, args->size))
>                         vma->vm_page_prot =
>                                 pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
>                 else
> -- 
> 2.17.2
> 

RE: [PATCH 1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

[Adam Zabrocki]

Thanks for the patch for both issues!

Best regards,
Adam

-----Original Message-----
From: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> 
Sent: Thursday, February 7, 2019 5:39 AM
To: Intel graphics driver community testing & development <intel-gfx@lists.freedesktop.org>
Cc: stable@vger.kernel.org; Akash Goel <akash.goel@intel.com>; Chris Wilson <chris@chris-wilson.co.uk>; Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>; Adam Zabrocki <adamza@microsoft.com>
Subject: Re: [PATCH 1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

Quoting Joonas Lahtinen (2019-01-07 10:56:55)
> Make sure the underlying VMA in the process address space is the same 
> as it was during vm_mmap to avoid applying WC to wrong VMA.
> 
> A more long-term solution would be to have vm_mmap_locked variant in 
> linux/mmap.h for when caller wants to hold mmap_sem for an extended 
> duration.

These are now merged to drm-tip, and will head to 5.1 and then to stable kernels.

Thanks for the report and reviews!

Regards, Joonas

> Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user 
> mappings for objects")
> Reported-by: Adam Zabrocki <adamza@microsoft.com>
> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v4.0+
> Cc: Akash Goel <akash.goel@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: Adam Zabrocki <adamza@microsoft.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c 
> b/drivers/gpu/drm/i915/i915_gem.c index 062c8395557c..f1d594a53978 
> 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1680,6 +1680,15 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data,
>         return 0;
>  }
>  
> +static inline bool
> +match_gem_vma(struct vm_area_struct *vma, struct file *filp,
> +             unsigned long addr, unsigned long size) {
> +       return vma && vma->vm_file == filp &&
> +              vma->vm_start == addr &&
> +              (vma->vm_end - vma->vm_start) == size; }
> +
>  /**
>   * i915_gem_mmap_ioctl - Maps the contents of an object, returning the address
>   *                      it is mapped to.
> @@ -1738,7 +1747,7 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>                         return -EINTR;
>                 }
>                 vma = find_vma(mm, addr);
> -               if (vma)
> +               if (match_gem_vma(vma, obj->base.filp, addr, 
> + args->size))
>                         vma->vm_page_prot =
>                                 pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
>                 else
> --
> 2.17.2
> 

RE: [PATCH 1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

[Adam Zabrocki]

Thanks for the patch for both issues!

Best regards,
Adam

-----Original Message-----
From: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> 
Sent: Thursday, February 7, 2019 5:39 AM
To: Intel graphics driver community testing & development <intel-gfx@lists.freedesktop.org>
Cc: stable@vger.kernel.org; Akash Goel <akash.goel@intel.com>; Chris Wilson <chris@chris-wilson.co.uk>; Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>; Adam Zabrocki <adamza@microsoft.com>
Subject: Re: [PATCH 1/2] drm/i915: Prevent a race during I915_GEM_MMAP ioctl with WC set

Quoting Joonas Lahtinen (2019-01-07 10:56:55)
> Make sure the underlying VMA in the process address space is the same 
> as it was during vm_mmap to avoid applying WC to wrong VMA.
> 
> A more long-term solution would be to have vm_mmap_locked variant in 
> linux/mmap.h for when caller wants to hold mmap_sem for an extended 
> duration.

These are now merged to drm-tip, and will head to 5.1 and then to stable kernels.

Thanks for the report and reviews!

Regards, Joonas

> Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user 
> mappings for objects")
> Reported-by: Adam Zabrocki <adamza@microsoft.com>
> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v4.0+
> Cc: Akash Goel <akash.goel@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: Adam Zabrocki <adamza@microsoft.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c 
> b/drivers/gpu/drm/i915/i915_gem.c index 062c8395557c..f1d594a53978 
> 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1680,6 +1680,15 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data,
>         return 0;
>  }
>  
> +static inline bool
> +match_gem_vma(struct vm_area_struct *vma, struct file *filp,
> +             unsigned long addr, unsigned long size) {
> +       return vma && vma->vm_file == filp &&
> +              vma->vm_start == addr &&
> +              (vma->vm_end - vma->vm_start) == size; }
> +
>  /**
>   * i915_gem_mmap_ioctl - Maps the contents of an object, returning the address
>   *                      it is mapped to.
> @@ -1738,7 +1747,7 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>                         return -EINTR;
>                 }
>                 vma = find_vma(mm, addr);
> -               if (vma)
> +               if (match_gem_vma(vma, obj->base.filp, addr, 
> + args->size))
>                         vma->vm_page_prot =
>                                 pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
>                 else
> --
> 2.17.2
>