alloc_slots could fail to allocate memory under heavy memory pressure. So
we should check zhdr->slots against NULL to avoid future null pointer
dereferencing.
Fixes: fc5488651c7d ("z3fold: simplify freeing slots")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
---
mm/z3fold.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/mm/z3fold.c b/mm/z3fold.c
index c2260f5a5885..5d8c21f2bc59 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -940,9 +940,19 @@ static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool,
}
}
- if (zhdr && !zhdr->slots)
+ if (zhdr && !zhdr->slots) {
zhdr->slots = alloc_slots(pool, GFP_ATOMIC);
+ if (!zhdr->slots)
+ goto out_fail;
+ }
return zhdr;
+
+out_fail:
+ if (!kref_put(&zhdr->refcount, release_z3fold_page_locked)) {
+ add_to_unbuddied(pool, zhdr);
+ z3fold_page_unlock(zhdr);
+ }
+ return NULL;
}
/*
--
2.23.0
