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authorMiaohe Lin2022-04-29 14:40:43 +0800
committerakpm2022-05-27 09:33:43 -0700
commit7c61c35bbd6a888416e5a6de8ff8782a70d013d4 (patch)
treed062095fadf78cede1c32b05ceb42f05ad98d234
parent4c6bdb36408fbe4697eb9f1d95a3ddc1d2348448 (diff)
mm/z3fold: fix possible null pointer dereferencing
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. Link: https://lkml.kernel.org/r/20220429064051.61552-3-linmiaohe@huawei.com Fixes: fc5488651c7d ("z3fold: simplify freeing slots") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--mm/z3fold.c12
1 files changed, 11 insertions, 1 deletions
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 @@ lookup:
}
}
- 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;
}
/*