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Commit a242f426 authored by Al Viro's avatar Al Viro Committed by Mauro Carvalho Chehab
Browse files

[media] videobuf_vm_{open,close} race fixes 



just use videobuf_queue_lock(map->q) to protect map->count; vm_area_operations
->open() and ->close() are called just under vma->vm_mm->mmap_sem, which
doesn't help the drivers at all, since clonal VMAs are normally in different
address spaces...

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 0735647c

drivers/media/v4l2-core/videobuf-dma-contig.c

+7 −5
Original line number Diff line number Diff line
@@ -66,11 +66,14 @@ static void __videobuf_dc_free(struct device *dev, 
static void videobuf_vm_open(struct vm_area_struct *vma)

{

	struct videobuf_mapping *map = vma->vm_private_data;

	struct videobuf_queue *q = map->q;



	dev_dbg(map->q->dev, "vm_open %p [count=%u,vma=%08lx-%08lx]\n",

	dev_dbg(q->dev, "vm_open %p [count=%u,vma=%08lx-%08lx]\n",

		map, map->count, vma->vm_start, vma->vm_end);



	videobuf_queue_lock(q);

	map->count++;

	videobuf_queue_unlock(q);

}



static void videobuf_vm_close(struct vm_area_struct *vma)
@@ -82,12 +85,11 @@ static void videobuf_vm_close(struct vm_area_struct *vma) 
	dev_dbg(q->dev, "vm_close %p [count=%u,vma=%08lx-%08lx]\n",

		map, map->count, vma->vm_start, vma->vm_end);



	map->count--;

	if (0 == map->count) {

	videobuf_queue_lock(q);

	if (!--map->count) {

		struct videobuf_dma_contig_memory *mem;



		dev_dbg(q->dev, "munmap %p q=%p\n", map, q);

		videobuf_queue_lock(q);



		/* We need first to cancel streams, before unmapping */

		if (q->streaming)
@@ -126,8 +128,8 @@ static void videobuf_vm_close(struct vm_area_struct *vma) 


		kfree(map);



		videobuf_queue_unlock(q);

	}

	videobuf_queue_unlock(q);

}



static const struct vm_operations_struct videobuf_vm_ops = {

drivers/media/v4l2-core/videobuf-dma-sg.c

+6 −4
Original line number Diff line number Diff line
@@ -338,11 +338,14 @@ EXPORT_SYMBOL_GPL(videobuf_dma_free); 
static void videobuf_vm_open(struct vm_area_struct *vma)

{

	struct videobuf_mapping *map = vma->vm_private_data;

	struct videobuf_queue *q = map->q;



	dprintk(2, "vm_open %p [count=%d,vma=%08lx-%08lx]\n", map,

		map->count, vma->vm_start, vma->vm_end);



	videobuf_queue_lock(q);

	map->count++;

	videobuf_queue_unlock(q);

}



static void videobuf_vm_close(struct vm_area_struct *vma)
@@ -355,10 +358,9 @@ static void videobuf_vm_close(struct vm_area_struct *vma) 
	dprintk(2, "vm_close %p [count=%d,vma=%08lx-%08lx]\n", map,

		map->count, vma->vm_start, vma->vm_end);



	map->count--;

	if (0 == map->count) {

		dprintk(1, "munmap %p q=%p\n", map, q);

	videobuf_queue_lock(q);

	if (!--map->count) {

		dprintk(1, "munmap %p q=%p\n", map, q);

		for (i = 0; i < VIDEO_MAX_FRAME; i++) {

			if (NULL == q->bufs[i])

				continue;
@@ -374,9 +376,9 @@ static void videobuf_vm_close(struct vm_area_struct *vma) 
			q->bufs[i]->baddr = 0;

			q->ops->buf_release(q, q->bufs[i]);

		}

		videobuf_queue_unlock(q);

		kfree(map);

	}

	videobuf_queue_unlock(q);

	return;

}

drivers/media/v4l2-core/videobuf-vmalloc.c

+6 −4
Original line number Diff line number Diff line
@@ -54,11 +54,14 @@ MODULE_LICENSE("GPL"); 
static void videobuf_vm_open(struct vm_area_struct *vma)

{

	struct videobuf_mapping *map = vma->vm_private_data;

	struct videobuf_queue *q = map->q;



	dprintk(2, "vm_open %p [count=%u,vma=%08lx-%08lx]\n", map,

		map->count, vma->vm_start, vma->vm_end);



	videobuf_queue_lock(q);

	map->count++;

	videobuf_queue_unlock(q);

}



static void videobuf_vm_close(struct vm_area_struct *vma)
@@ -70,12 +73,11 @@ static void videobuf_vm_close(struct vm_area_struct *vma) 
	dprintk(2, "vm_close %p [count=%u,vma=%08lx-%08lx]\n", map,

		map->count, vma->vm_start, vma->vm_end);



	map->count--;

	if (0 == map->count) {

	videobuf_queue_lock(q);

	if (!--map->count) {

		struct videobuf_vmalloc_memory *mem;



		dprintk(1, "munmap %p q=%p\n", map, q);

		videobuf_queue_lock(q);



		/* We need first to cancel streams, before unmapping */

		if (q->streaming)
@@ -114,8 +116,8 @@ static void videobuf_vm_close(struct vm_area_struct *vma) 


		kfree(map);



		videobuf_queue_unlock(q);

	}

	videobuf_queue_unlock(q);



	return;

}