author: Chen Wandun <chenwandun@huawei.com> 2021-09-02 14:57:26 -0700
committer: Linus Torvalds <torvalds@linux-foundation.org> 2021-09-03 09:58:14 -0700
commit: f181234a5a21fd0a86b793330016b92c7b3ed8ee
parent: f8bcbecfb6b48c026e2205679c063d1f16f5a2c0
Commit Summary:
Diffstat:
1 file changed, 23 insertions, 1 deletion
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 5dcb65dd9bf3..3824dc16ce1c 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -787,6 +787,28 @@ unsigned long vmalloc_nr_pages(void)
return atomic_long_read(&nr_vmalloc_pages);
}
+static struct vmap_area *find_vmap_area_exceed_addr(unsigned long addr)
+{
+ struct vmap_area *va = NULL;
+ struct rb_node *n = vmap_area_root.rb_node;
+
+ while (n) {
+ struct vmap_area *tmp;
+
+ tmp = rb_entry(n, struct vmap_area, rb_node);
+ if (tmp->va_end > addr) {
+ va = tmp;
+ if (tmp->va_start <= addr)
+ break;
+
+ n = n->rb_left;
+ } else
+ n = n->rb_right;
+ }
+
+ return va;
+}
+
static struct vmap_area *__find_vmap_area(unsigned long addr)
{
struct rb_node *n = vmap_area_root.rb_node;
@@ -3287,9 +3309,14 @@ long vread(char *buf, char *addr, unsigned long count)
count = -(unsigned long) addr;
spin_lock(&vmap_area_lock);
- va = __find_vmap_area((unsigned long)addr);
+ va = find_vmap_area_exceed_addr((unsigned long)addr);
if (!va)
goto finished;
+
+ /* no intersects with alive vmap_area */
+ if ((unsigned long)addr + count <= va->va_start)
+ goto finished;
+
list_for_each_entry_from(va, &vmap_area_list, list) {
if (!count)
break;