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Commit 28a326c5 authored by Maarten Lankhorst's avatar Maarten Lankhorst Committed by Alex Deucher
Browse files

drm/radeon: fixup locking inversion between, mmap_sem and reservations 



op 08-10-13 18:58, Thomas Hellstrom schreef:
> On 10/08/2013 06:47 PM, Jerome Glisse wrote:
>> On Tue, Oct 08, 2013 at 06:29:35PM +0200, Thomas Hellstrom wrote:
>>> On 10/08/2013 04:55 PM, Jerome Glisse wrote:
>>>> On Tue, Oct 08, 2013 at 04:45:18PM +0200, Christian König wrote:
>>>>> Am 08.10.2013 16:33, schrieb Jerome Glisse:
>>>>>> On Tue, Oct 08, 2013 at 04:14:40PM +0200, Maarten Lankhorst wrote:
>>>>>>> Allocate and copy all kernel memory before doing reservations. This prevents a locking
>>>>>>> inversion between mmap_sem and reservation_class, and allows us to drop the trylocking
>>>>>>> in ttm_bo_vm_fault without upsetting lockdep.
>>>>>>>
>>>>>>> Signed-off-by: default avatarMaarten Lankhorst <maarten.lankhorst@canonical.com>
>>>>>> I would say NAK. Current code only allocate temporary page in AGP case.
>>>>>> So AGP case is userspace -> temp page -> cs checker -> radeon ib.
>>>>>>
>>>>>> Non AGP is directly memcpy to radeon IB.
>>>>>>
>>>>>> Your patch allocate memory memcpy userspace to it and it will then be
>>>>>> memcpy to IB. Which means you introduce an extra memcpy in the process
>>>>>> not something we want.
>>>>> Totally agree. Additional to that there is no good reason to provide
>>>>> anything else than anonymous system memory to the CS ioctl, so the
>>>>> dependency between the mmap_sem and reservations are not really
>>>>> clear to me.
>>>>>
>>>>> Christian.
>>>> I think is that in other code path you take mmap_sem first then reserve
>>>> bo. But here we reserve bo and then we take mmap_sem because of copy
>>> >from user.
>>>> Cheers,
>>>> Jerome
>>>>
>>> Actually the log message is a little confusing. I think the mmap_sem
>>> locking inversion problem is orthogonal to what's being fixed here.
>>>
>>> This patch fixes the possible recursive bo::reserve caused by
>>> malicious user-space handing a pointer to ttm memory so that the ttm
>>> fault handler is called when bos are already reserved. That may
>>> cause a (possibly interruptible) livelock.
>>>
>>> Once that is fixed, we are free to choose the mmap_sem ->
>>> bo::reserve locking order. Currently it's bo::reserve->mmap_sem(),
>>> but the hack required in the ttm fault handler is admittedly a bit
>>> ugly.  The plan is to change the locking order to
>>> mmap_sem->bo::reserve
>>>
>>> I'm not sure if it applies to this particular case, but it should be
>>> possible to make sure that copy_from_user_inatomic() will always
>>> succeed, by making sure the pages are present using
>>> get_user_pages(), and release the pages after
>>> copy_from_user_inatomic() is done. That way there's no need for a
>>> double memcpy slowpath, but if the copied data is very fragmented I
>>> guess the resulting code may look ugly. The get_user_pages()
>>> function will return an error if it hits TTM pages.
>>>
>>> /Thomas
>> get_user_pages + copy_from_user_inatomic is overkill. We should just
>> do get_user_pages which fails with ttm memory and then use copy_highpage
>> helper.
>>
>> Cheers,
>> Jerome
> Yeah, it may well be that that's the preferred solution.
>
> /Thomas
>
I still disagree, and shuffled radeon_ib_get around to be called sooner.

How does the patch below look?
8<-------
Allocate and copy all kernel memory before doing reservations. This prevents a locking
inversion between mmap_sem and reservation_class, and allows us to drop the trylocking
in ttm_bo_vm_fault without upsetting lockdep.

Changes since v1:
- Kill extra memcpy for !AGP case.

Signed-off-by: default avatarMaarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: default avatarJerome Glisse <jglisse@redhat.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent db96bd25

drivers/gpu/drm/radeon/r600_cs.c

+5 −11
Original line number Diff line number Diff line
@@ -2328,13 +2328,8 @@ static void r600_cs_parser_fini(struct radeon_cs_parser *parser, int error) 
	unsigned i;



	kfree(parser->relocs);

	for (i = 0; i < parser->nchunks; i++) {

		kfree(parser->chunks[i].kdata);

		if (parser->rdev && (parser->rdev->flags & RADEON_IS_AGP)) {

			kfree(parser->chunks[i].kpage[0]);

			kfree(parser->chunks[i].kpage[1]);

		}

	}

	for (i = 0; i < parser->nchunks; i++)

		drm_free_large(parser->chunks[i].kdata);

	kfree(parser->chunks);

	kfree(parser->chunks_array);

}
@@ -2391,13 +2386,12 @@ int r600_cs_legacy(struct drm_device *dev, void *data, struct drm_file *filp, 
	ib_chunk = &parser.chunks[parser.chunk_ib_idx];

	parser.ib.length_dw = ib_chunk->length_dw;

	*l = parser.ib.length_dw;

	r = r600_cs_parse(&parser);

	if (r) {

		DRM_ERROR("Invalid command stream !\n");

	if (DRM_COPY_FROM_USER(ib, ib_chunk->user_ptr, ib_chunk->length_dw * 4)) {

		r = -EFAULT;

		r600_cs_parser_fini(&parser, r);

		return r;

	}

	r = radeon_cs_finish_pages(&parser);

	r = r600_cs_parse(&parser);

	if (r) {

		DRM_ERROR("Invalid command stream !\n");

		r600_cs_parser_fini(&parser, r);

drivers/gpu/drm/radeon/radeon.h

+9 −6
Original line number Diff line number Diff line
@@ -973,12 +973,8 @@ struct radeon_cs_reloc { 
struct radeon_cs_chunk {

	uint32_t		chunk_id;

	uint32_t		length_dw;

	int			kpage_idx[2];

	uint32_t		*kpage[2];

	uint32_t		*kdata;

	void __user		*user_ptr;

	int			last_copied_page;

	int			last_page_index;

};



struct radeon_cs_parser {
@@ -1013,8 +1009,15 @@ struct radeon_cs_parser { 
	struct ww_acquire_ctx	ticket;

};



extern int radeon_cs_finish_pages(struct radeon_cs_parser *p);

extern u32 radeon_get_ib_value(struct radeon_cs_parser *p, int idx);

static inline u32 radeon_get_ib_value(struct radeon_cs_parser *p, int idx)

{

	struct radeon_cs_chunk *ibc = &p->chunks[p->chunk_ib_idx];



	if (ibc->kdata)

		return ibc->kdata[idx];

	return p->ib.ptr[idx];

}





struct radeon_cs_packet {

	unsigned	idx;

drivers/gpu/drm/radeon/radeon_cs.c

+92 −206
Original line number Diff line number Diff line
@@ -213,9 +213,7 @@ int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data) 
			return -EFAULT;

		}

		p->chunks[i].length_dw = user_chunk.length_dw;

		p->chunks[i].kdata = NULL;

		p->chunks[i].chunk_id = user_chunk.chunk_id;

		p->chunks[i].user_ptr = (void __user *)(unsigned long)user_chunk.chunk_data;

		if (p->chunks[i].chunk_id == RADEON_CHUNK_ID_RELOCS) {

			p->chunk_relocs_idx = i;

		}
@@ -238,16 +236,23 @@ int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data) 
				return -EINVAL;

		}



		cdata = (uint32_t *)(unsigned long)user_chunk.chunk_data;

		if ((p->chunks[i].chunk_id == RADEON_CHUNK_ID_RELOCS) ||

		    (p->chunks[i].chunk_id == RADEON_CHUNK_ID_FLAGS)) {

			size = p->chunks[i].length_dw * sizeof(uint32_t);

			p->chunks[i].kdata = kmalloc(size, GFP_KERNEL);

		size = p->chunks[i].length_dw;

		cdata = (void __user *)(unsigned long)user_chunk.chunk_data;

		p->chunks[i].user_ptr = cdata;

		if (p->chunks[i].chunk_id == RADEON_CHUNK_ID_CONST_IB)

			continue;



		if (p->chunks[i].chunk_id == RADEON_CHUNK_ID_IB) {

			if (!p->rdev || !(p->rdev->flags & RADEON_IS_AGP))

				continue;

		}



		p->chunks[i].kdata = drm_malloc_ab(size, sizeof(uint32_t));

		size *= sizeof(uint32_t);

		if (p->chunks[i].kdata == NULL) {

			return -ENOMEM;

		}

			if (DRM_COPY_FROM_USER(p->chunks[i].kdata,

					       p->chunks[i].user_ptr, size)) {

		if (DRM_COPY_FROM_USER(p->chunks[i].kdata, cdata, size)) {

			return -EFAULT;

		}

		if (p->chunks[i].chunk_id == RADEON_CHUNK_ID_FLAGS) {
@@ -258,7 +263,6 @@ int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data) 
				priority = (s32)p->chunks[i].kdata[2];

		}

	}

	}



	/* these are KMS only */

	if (p->rdev) {
@@ -279,34 +283,6 @@ int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data) 
		}

	}



	/* deal with non-vm */

	if ((p->chunk_ib_idx != -1) &&

	    ((p->cs_flags & RADEON_CS_USE_VM) == 0) &&

	    (p->chunks[p->chunk_ib_idx].chunk_id == RADEON_CHUNK_ID_IB)) {

		if (p->chunks[p->chunk_ib_idx].length_dw > (16 * 1024)) {

			DRM_ERROR("cs IB too big: %d\n",

				  p->chunks[p->chunk_ib_idx].length_dw);

			return -EINVAL;

		}

		if (p->rdev && (p->rdev->flags & RADEON_IS_AGP)) {

			p->chunks[p->chunk_ib_idx].kpage[0] = kmalloc(PAGE_SIZE, GFP_KERNEL);

			p->chunks[p->chunk_ib_idx].kpage[1] = kmalloc(PAGE_SIZE, GFP_KERNEL);

			if (p->chunks[p->chunk_ib_idx].kpage[0] == NULL ||

			    p->chunks[p->chunk_ib_idx].kpage[1] == NULL) {

				kfree(p->chunks[p->chunk_ib_idx].kpage[0]);

				kfree(p->chunks[p->chunk_ib_idx].kpage[1]);

				p->chunks[p->chunk_ib_idx].kpage[0] = NULL;

				p->chunks[p->chunk_ib_idx].kpage[1] = NULL;

				return -ENOMEM;

			}

		}

		p->chunks[p->chunk_ib_idx].kpage_idx[0] = -1;

		p->chunks[p->chunk_ib_idx].kpage_idx[1] = -1;

		p->chunks[p->chunk_ib_idx].last_copied_page = -1;

		p->chunks[p->chunk_ib_idx].last_page_index =

			((p->chunks[p->chunk_ib_idx].length_dw * 4) - 1) / PAGE_SIZE;

	}



	return 0;

}
@@ -340,13 +316,8 @@ static void radeon_cs_parser_fini(struct radeon_cs_parser *parser, int error, bo 
	kfree(parser->track);

	kfree(parser->relocs);

	kfree(parser->relocs_ptr);

	for (i = 0; i < parser->nchunks; i++) {

		kfree(parser->chunks[i].kdata);

		if ((parser->rdev->flags & RADEON_IS_AGP)) {

			kfree(parser->chunks[i].kpage[0]);

			kfree(parser->chunks[i].kpage[1]);

		}

	}

	for (i = 0; i < parser->nchunks; i++)

		drm_free_large(parser->chunks[i].kdata);

	kfree(parser->chunks);

	kfree(parser->chunks_array);

	radeon_ib_free(parser->rdev, &parser->ib);
@@ -356,7 +327,6 @@ static void radeon_cs_parser_fini(struct radeon_cs_parser *parser, int error, bo 
static int radeon_cs_ib_chunk(struct radeon_device *rdev,

			      struct radeon_cs_parser *parser)

{

	struct radeon_cs_chunk *ib_chunk;

	int r;



	if (parser->chunk_ib_idx == -1)
@@ -365,28 +335,11 @@ static int radeon_cs_ib_chunk(struct radeon_device *rdev, 
	if (parser->cs_flags & RADEON_CS_USE_VM)

		return 0;



	ib_chunk = &parser->chunks[parser->chunk_ib_idx];

	/* Copy the packet into the IB, the parser will read from the

	 * input memory (cached) and write to the IB (which can be

	 * uncached).

	 */

	r =  radeon_ib_get(rdev, parser->ring, &parser->ib,

			   NULL, ib_chunk->length_dw * 4);

	if (r) {

		DRM_ERROR("Failed to get ib !\n");

		return r;

	}

	parser->ib.length_dw = ib_chunk->length_dw;

	r = radeon_cs_parse(rdev, parser->ring, parser);

	if (r || parser->parser_error) {

		DRM_ERROR("Invalid command stream !\n");

		return r;

	}

	r = radeon_cs_finish_pages(parser);

	if (r) {

		DRM_ERROR("Invalid command stream !\n");

		return r;

	}



	if (parser->ring == R600_RING_TYPE_UVD_INDEX)

		radeon_uvd_note_usage(rdev);
@@ -424,7 +377,6 @@ static int radeon_bo_vm_update_pte(struct radeon_cs_parser *parser, 
static int radeon_cs_ib_vm_chunk(struct radeon_device *rdev,

				 struct radeon_cs_parser *parser)

{

	struct radeon_cs_chunk *ib_chunk;

	struct radeon_fpriv *fpriv = parser->filp->driver_priv;

	struct radeon_vm *vm = &fpriv->vm;

	int r;
@@ -434,49 +386,13 @@ static int radeon_cs_ib_vm_chunk(struct radeon_device *rdev, 
	if ((parser->cs_flags & RADEON_CS_USE_VM) == 0)

		return 0;



	if ((rdev->family >= CHIP_TAHITI) &&

	    (parser->chunk_const_ib_idx != -1)) {

		ib_chunk = &parser->chunks[parser->chunk_const_ib_idx];

		if (ib_chunk->length_dw > RADEON_IB_VM_MAX_SIZE) {

			DRM_ERROR("cs IB CONST too big: %d\n", ib_chunk->length_dw);

			return -EINVAL;

		}

		r =  radeon_ib_get(rdev, parser->ring, &parser->const_ib,

				   vm, ib_chunk->length_dw * 4);

		if (r) {

			DRM_ERROR("Failed to get const ib !\n");

			return r;

		}

		parser->const_ib.is_const_ib = true;

		parser->const_ib.length_dw = ib_chunk->length_dw;

		/* Copy the packet into the IB */

		if (DRM_COPY_FROM_USER(parser->const_ib.ptr, ib_chunk->user_ptr,

				       ib_chunk->length_dw * 4)) {

			return -EFAULT;

		}

	if (parser->const_ib.length_dw) {

		r = radeon_ring_ib_parse(rdev, parser->ring, &parser->const_ib);

		if (r) {

			return r;

		}

	}



	ib_chunk = &parser->chunks[parser->chunk_ib_idx];

	if (ib_chunk->length_dw > RADEON_IB_VM_MAX_SIZE) {

		DRM_ERROR("cs IB too big: %d\n", ib_chunk->length_dw);

		return -EINVAL;

	}

	r =  radeon_ib_get(rdev, parser->ring, &parser->ib,

			   vm, ib_chunk->length_dw * 4);

	if (r) {

		DRM_ERROR("Failed to get ib !\n");

		return r;

	}

	parser->ib.length_dw = ib_chunk->length_dw;

	/* Copy the packet into the IB */

	if (DRM_COPY_FROM_USER(parser->ib.ptr, ib_chunk->user_ptr,

			       ib_chunk->length_dw * 4)) {

		return -EFAULT;

	}

	r = radeon_ring_ib_parse(rdev, parser->ring, &parser->ib);

	if (r) {

		return r;
@@ -528,6 +444,62 @@ static int radeon_cs_handle_lockup(struct radeon_device *rdev, int r) 
	return r;

}



static int radeon_cs_ib_fill(struct radeon_device *rdev, struct radeon_cs_parser *parser)

{

	struct radeon_cs_chunk *ib_chunk;

	struct radeon_vm *vm = NULL;

	int r;



	if (parser->chunk_ib_idx == -1)

		return 0;



	if (parser->cs_flags & RADEON_CS_USE_VM) {

		struct radeon_fpriv *fpriv = parser->filp->driver_priv;

		vm = &fpriv->vm;



		if ((rdev->family >= CHIP_TAHITI) &&

		    (parser->chunk_const_ib_idx != -1)) {

			ib_chunk = &parser->chunks[parser->chunk_const_ib_idx];

			if (ib_chunk->length_dw > RADEON_IB_VM_MAX_SIZE) {

				DRM_ERROR("cs IB CONST too big: %d\n", ib_chunk->length_dw);

				return -EINVAL;

			}

			r =  radeon_ib_get(rdev, parser->ring, &parser->const_ib,

					   vm, ib_chunk->length_dw * 4);

			if (r) {

				DRM_ERROR("Failed to get const ib !\n");

				return r;

			}

			parser->const_ib.is_const_ib = true;

			parser->const_ib.length_dw = ib_chunk->length_dw;

			if (DRM_COPY_FROM_USER(parser->const_ib.ptr,

					       ib_chunk->user_ptr,

					       ib_chunk->length_dw * 4))

				return -EFAULT;

		}



		ib_chunk = &parser->chunks[parser->chunk_ib_idx];

		if (ib_chunk->length_dw > RADEON_IB_VM_MAX_SIZE) {

			DRM_ERROR("cs IB too big: %d\n", ib_chunk->length_dw);

			return -EINVAL;

		}

	}

	ib_chunk = &parser->chunks[parser->chunk_ib_idx];



	r =  radeon_ib_get(rdev, parser->ring, &parser->ib,

			   vm, ib_chunk->length_dw * 4);

	if (r) {

		DRM_ERROR("Failed to get ib !\n");

		return r;

	}

	parser->ib.length_dw = ib_chunk->length_dw;

	if (ib_chunk->kdata)

		memcpy(parser->ib.ptr, ib_chunk->kdata, ib_chunk->length_dw * 4);

	else if (DRM_COPY_FROM_USER(parser->ib.ptr, ib_chunk->user_ptr, ib_chunk->length_dw * 4))

		return -EFAULT;

	return 0;

}



int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)

{

	struct radeon_device *rdev = dev->dev_private;
@@ -553,10 +525,15 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp) 
		r = radeon_cs_handle_lockup(rdev, r);

		return r;

	}



	r = radeon_cs_ib_fill(rdev, &parser);

	if (!r) {

		r = radeon_cs_parser_relocs(&parser);

	if (r) {

		if (r != -ERESTARTSYS)

		if (r && r != -ERESTARTSYS)

			DRM_ERROR("Failed to parse relocation %d!\n", r);

	}



	if (r) {

		radeon_cs_parser_fini(&parser, r, false);

		up_read(&rdev->exclusive_lock);

		r = radeon_cs_handle_lockup(rdev, r);
@@ -580,97 +557,6 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp) 
	return r;

}



int radeon_cs_finish_pages(struct radeon_cs_parser *p)

{

	struct radeon_cs_chunk *ibc = &p->chunks[p->chunk_ib_idx];

	int i;

	int size = PAGE_SIZE;



	for (i = ibc->last_copied_page + 1; i <= ibc->last_page_index; i++) {

		if (i == ibc->last_page_index) {

			size = (ibc->length_dw * 4) % PAGE_SIZE;

			if (size == 0)

				size = PAGE_SIZE;

		}

		

		if (DRM_COPY_FROM_USER(p->ib.ptr + (i * (PAGE_SIZE/4)),

				       ibc->user_ptr + (i * PAGE_SIZE),

				       size))

			return -EFAULT;

	}

	return 0;

}



static int radeon_cs_update_pages(struct radeon_cs_parser *p, int pg_idx)

{

	int new_page;

	struct radeon_cs_chunk *ibc = &p->chunks[p->chunk_ib_idx];

	int i;

	int size = PAGE_SIZE;

	bool copy1 = (p->rdev && (p->rdev->flags & RADEON_IS_AGP)) ?

		false : true;



	for (i = ibc->last_copied_page + 1; i < pg_idx; i++) {

		if (DRM_COPY_FROM_USER(p->ib.ptr + (i * (PAGE_SIZE/4)),

				       ibc->user_ptr + (i * PAGE_SIZE),

				       PAGE_SIZE)) {

			p->parser_error = -EFAULT;

			return 0;

		}

	}



	if (pg_idx == ibc->last_page_index) {

		size = (ibc->length_dw * 4) % PAGE_SIZE;

		if (size == 0)

			size = PAGE_SIZE;

	}



	new_page = ibc->kpage_idx[0] < ibc->kpage_idx[1] ? 0 : 1;

	if (copy1)

		ibc->kpage[new_page] = p->ib.ptr + (pg_idx * (PAGE_SIZE / 4));



	if (DRM_COPY_FROM_USER(ibc->kpage[new_page],

			       ibc->user_ptr + (pg_idx * PAGE_SIZE),

			       size)) {

		p->parser_error = -EFAULT;

		return 0;

	}



	/* copy to IB for non single case */

	if (!copy1)

		memcpy((void *)(p->ib.ptr+(pg_idx*(PAGE_SIZE/4))), ibc->kpage[new_page], size);



	ibc->last_copied_page = pg_idx;

	ibc->kpage_idx[new_page] = pg_idx;



	return new_page;

}



u32 radeon_get_ib_value(struct radeon_cs_parser *p, int idx)

{

	struct radeon_cs_chunk *ibc = &p->chunks[p->chunk_ib_idx];

	u32 pg_idx, pg_offset;

	u32 idx_value = 0;

	int new_page;



	pg_idx = (idx * 4) / PAGE_SIZE;

	pg_offset = (idx * 4) % PAGE_SIZE;



	if (ibc->kpage_idx[0] == pg_idx)

		return ibc->kpage[0][pg_offset/4];

	if (ibc->kpage_idx[1] == pg_idx)

		return ibc->kpage[1][pg_offset/4];



	new_page = radeon_cs_update_pages(p, pg_idx);

	if (new_page < 0) {

		p->parser_error = new_page;

		return 0;

	}



	idx_value = ibc->kpage[new_page][pg_offset/4];

	return idx_value;

}



/**

 * radeon_cs_packet_parse() - parse cp packet and point ib index to next packet

 * @parser:	parser structure holding parsing context.