[PATCH][next] mm/vmalloc: Fix read of pointer area after it has been free'd

From: Colin King
Date: Mon Mar 29 2021 - 13:08:33 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

Currently the memory pointed to by area is being freed by the
free_vm_area call and then area->nr_pages is referencing the
free'd object. Fix this swapping the order of the warn_alloc
message and the free.

Addresses-Coverity: ("Read from pointer after free")
Fixes: 014ccf9b888d ("mm/vmalloc: improve allocation failure error messages")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
mm/vmalloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index b73e4e715e0d..7936405749e4 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2790,11 +2790,11 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
}

if (!pages) {
- free_vm_area(area);
warn_alloc(gfp_mask, NULL,
"vmalloc size %lu allocation failure: "
"page array size %lu allocation failed",
area->nr_pages * PAGE_SIZE, array_size);
+ free_vm_area(area);
return NULL;
}

--
2.30.2