Zero spare memory when shrinking a buffer with __GFP_ZERO.
Fixes: 1f39ee9615a8 ("mm: vmalloc: implement vrealloc()")
Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx>
---
mm/vmalloc.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 2a6d4ce57b73..6a2fef6378e4 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -4077,12 +4077,15 @@ void *vrealloc_noprof(const void *p, size_t size, gfp_t flags)
old_size = get_vm_area_size(vm);
}
+ /*
+ * TODO: Shrink the vm_area, i.e. unmap and free unused pages. What
+ * would be a good heuristic for when to shrink the vm_area?
+ */
if (size <= old_size) {
- /*
- * TODO: Shrink the vm_area, i.e. unmap and free unused pages.
- * What would be a good heuristic for when to shrink the
- * vm_area?
- */
+ /* Zero out spare memory. */
+ if (want_init_on_alloc(flags))
+ memset((void *)p + size, 0, old_size - size);
+
return (void *)p;
}
--
2.45.2
