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-rw-r--r--kernel/bpf/arena.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c
index 343c3456c8..a59ae9c582 100644
--- a/kernel/bpf/arena.c
+++ b/kernel/bpf/arena.c
@@ -212,6 +212,7 @@ static u64 arena_map_mem_usage(const struct bpf_map *map)
struct vma_list {
struct vm_area_struct *vma;
struct list_head head;
+ atomic_t mmap_count;
};
static int remember_vma(struct bpf_arena *arena, struct vm_area_struct *vma)
@@ -221,20 +222,30 @@ static int remember_vma(struct bpf_arena *arena, struct vm_area_struct *vma)
vml = kmalloc(sizeof(*vml), GFP_KERNEL);
if (!vml)
return -ENOMEM;
+ atomic_set(&vml->mmap_count, 1);
vma->vm_private_data = vml;
vml->vma = vma;
list_add(&vml->head, &arena->vma_list);
return 0;
}
+static void arena_vm_open(struct vm_area_struct *vma)
+{
+ struct vma_list *vml = vma->vm_private_data;
+
+ atomic_inc(&vml->mmap_count);
+}
+
static void arena_vm_close(struct vm_area_struct *vma)
{
struct bpf_map *map = vma->vm_file->private_data;
struct bpf_arena *arena = container_of(map, struct bpf_arena, map);
- struct vma_list *vml;
+ struct vma_list *vml = vma->vm_private_data;
+ if (!atomic_dec_and_test(&vml->mmap_count))
+ return;
guard(mutex)(&arena->lock);
- vml = vma->vm_private_data;
+ /* update link list under lock */
list_del(&vml->head);
vma->vm_private_data = NULL;
kfree(vml);
@@ -287,6 +298,7 @@ out:
}
static const struct vm_operations_struct arena_vm_ops = {
+ .open = arena_vm_open,
.close = arena_vm_close,
.fault = arena_vm_fault,
};