[PATCH] mm: Avoid a risk of null pointer.

From: jiping huang
Date: Mon Aug 19 2024 - 10:56:55 EST


There is a probability that we will get a null pointer when we use
find_vm() interface.

Signed-off-by: jiping huang <huangjiping95@xxxxxx>

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index aec756ae5637..a0bcc1865c62 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1079,6 +1079,11 @@ static long migrate_to_node(struct mm_struct *mm, int source, int dest,
mmap_read_lock(mm);
vma = find_vma(mm, 0);

+ if (!vma) {
+ mmap_read_unlock(mm);
+ return -EFAULT;
+ }
+
/*
* This does not migrate the range, but isolates all pages that
* need migration. Between passing in the full user address
--
2.34.1