Andrew,
On 8/10/2021 6:18 PM, akpm@xxxxxxxxxxxxxxxxxxxx wrote:
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
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------------------------------------------------------
From: Nathan Chancellor <nathan@xxxxxxxxxx>
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@xxxxxxxxxx
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Feng Tang <feng.tang@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxx are
mm-hugetlb-initialize-page-to-null-in-alloc_buddy_huge_page_with_mpol.patch
Sorry for not making it clearer with a fixes tag but I did not intend
for this to be a standalone patch but rather a fixup patch for
mm-hugetlb-add-support-for-mempolicy-mpol_preferred_many-fix.patch,
which fails to initialize page in alloc_buddy_huge_page_with_mpol(). I
thought that replying inline to the thread would be enough.
Cheers,
Nathan
