[PATCH] nommu: Fix memory leak in do_mmap() error path

From: Liam Howlett
Date: Mon Jan 09 2023 - 16:00:45 EST


The preallocation of the maple tree nodes may leak if the error path to
"error_just_free" is taken. Fix this by moving the freeing of the maple
tree nodes to a shared location for all error paths.

Fixes: 8220543df148 ("nommu: remove uses of VMA linked list")
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
---
mm/nommu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/nommu.c b/mm/nommu.c
index 214c70e1d059..c8252f01d5db 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1240,6 +1240,7 @@ unsigned long do_mmap(struct file *file,
error_just_free:
up_write(&nommu_region_sem);
error:
+ mas_destroy(&mas);
if (region->vm_file)
fput(region->vm_file);
kmem_cache_free(vm_region_jar, region);
@@ -1250,7 +1251,6 @@ unsigned long do_mmap(struct file *file,

sharing_violation:
up_write(&nommu_region_sem);
- mas_destroy(&mas);
pr_warn("Attempt to share mismatched mappings\n");
ret = -EINVAL;
goto error;
--
2.35.1