+ mm-hugetlb-initialize-page-to-null-in-alloc_buddy_huge_page_with_mpol.patch added to -mm tree

[akpm@linux-foundation.org]

The patch titled
     Subject: mm/hugetlb: Initialize page to NULL in alloc_buddy_huge_page_with_mpol()
has been added to the -mm tree.  Its filename is
     mm-hugetlb-initialize-page-to-null-in-alloc_buddy_huge_page_with_mpol.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb-initialize-page-to-null-in-alloc_buddy_huge_page_with_mpol.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb-initialize-page-to-null-in-alloc_buddy_huge_page_with_mpol.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Nathan Chancellor <nathan@kernel.org>
Subject: mm/hugetlb: Initialize page to NULL in alloc_buddy_huge_page_with_mpol()

Clang warns:

mm/hugetlb.c:2162:6: warning: variable 'page' is used uninitialized
whenever 'if' condition is false [-Wsometimes-uninitialized]
        if (mpol_is_preferred_many(mpol)) {
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
mm/hugetlb.c:2172:7: note: uninitialized use occurs here
        if (!page)
             ^~~~
mm/hugetlb.c:2162:2: note: remove the 'if' if its condition is always
true
        if (mpol_is_preferred_many(mpol)) {
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mm/hugetlb.c:2155:19: note: initialize the variable 'page' to silence
this warning
        struct page *page;
                         ^
                          = NULL
1 warning generated.

Initialize page to NULL like in dequeue_huge_page_vma() so that page is
not used uninitialized.

Link: https://lkml.kernel.org/r/20210810200632.3812797-1-nathan@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Feng Tang <feng.tang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/hugetlb.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/hugetlb.c~mm-hugetlb-initialize-page-to-null-in-alloc_buddy_huge_page_with_mpol
+++ a/mm/hugetlb.c
@@ -2088,7 +2088,7 @@ static
 struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
 		struct vm_area_struct *vma, unsigned long addr)
 {
-	struct page *page;
+	struct page *page = NULL;
 	struct mempolicy *mpol;
 	gfp_t gfp_mask = htlb_alloc_mask(h);
 	int nid;
_

Patches currently in -mm which might be from nathan@kernel.org are

mm-hugetlb-initialize-page-to-null-in-alloc_buddy_huge_page_with_mpol.patch