The quilt patch titled
Subject: mm/z3fold: fix possible null pointer dereferencing
has been removed from the -mm tree. Its filename was
mm-z3fold-fix-possible-null-pointer-dereferencing.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/z3fold: fix possible null pointer dereferencing
Date: Fri, 29 Apr 2022 14:40:43 +0800
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@xxxxxxxxxx
Fixes: fc5488651c7d ("z3fold: simplify freeing slots")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/z3fold.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
--- a/mm/z3fold.c~mm-z3fold-fix-possible-null-pointer-dereferencing
+++ a/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;
}
/*
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
