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[media] videobuf_vm_{open,close} race fixes

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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: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Al Viro 2013-05-09 15:03:33 -03:00 committed by Mauro Carvalho Chehab
parent 0735647c29
commit a242f42610
3 changed files with 19 additions and 13 deletions
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12
drivers/media/v4l2-core/videobuf-dma-contig.c
View File

@ -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 = {

10
drivers/media/v4l2-core/videobuf-dma-sg.c
View File

@ -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) {
videobuf_queue_lock(q);
if (!--map->count) {
dprintk(1, "munmap %p q=%p\n", map, q);
videobuf_queue_lock(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;
}

10
drivers/media/v4l2-core/videobuf-vmalloc.c
View File

@ -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;
}