nommu: fix memory leak in do_mmap() error path

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.

Link: https://lkml.kernel.org/r/20230109205507.955577-1-Liam.Howlett@oracle.com
Fixes: 8220543df148 ("nommu: remove uses of VMA linked list")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yu Zhao <yuzhao@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/nommu.c b/mm/nommu.c
index 214c70e1d05942e8a0a9a2e4ece7a6f5086f9c62..c8252f01d5dbb4216b9548d8035628f8f1ea2d8a 100644 (file)
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1240,6 +1240,7 @@ share:
 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 @@ error:
 
 sharing_violation:
        up_write(&nommu_region_sem);
-       mas_destroy(&mas);
        pr_warn("Attempt to share mismatched mappings\n");
        ret = -EINVAL;
        goto error;