A file reference should be held while a file is mmaped, otherwise it might
be freed while being used.
Suggested-by: Hugh Dickins <hu...@google.com>
Signed-off-by: Sasha Levin <sasha.le...@oracle.com>
---
mm/mmap.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/mm/mmap.c b/mm/mmap.c
index 2a0e0a8..da3c212 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2593,6 +2593,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start,
unsigned long, size,
struct vm_area_struct *vma;
unsigned long populate = 0;
unsigned long ret = -EINVAL;
+ struct file *file;
pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. "
"See Documentation/vm/remap_file_pages.txt.\n",
@@ -2636,8 +2637,10 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start,
unsigned long, size,
munlock_vma_pages_range(vma, start, start + size);
}
+ file = get_file(vma->vm_file);
ret = do_mmap_pgoff(vma->vm_file, start, size,
prot, flags, pgoff, &populate);
+ fput(file);
out:
up_write(&mm->mmap_sem);
if (populate)
--
1.7.10.4
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