[bug report] Merge branch 'akpm-current/current'

[bug report] Merge branch 'akpm-current/current'

[Dan Carpenter]

[ I do a git show 2db9f815409f and it doesn't show that hugetlb.c was
  modified but it the git log the merge commit is listed.  I don't
  know git well enough to explain it.  But I think this was a merge
  issue.  - dan ]

Hello Stephen Rothwell,

The patch 2db9f815409f: "Merge branch 'akpm-current/current'" from
Aug 10, 2021, leads to the following
Smatch static checker warning:

	mm/hugetlb.c:2172 alloc_buddy_huge_page_with_mpol()
	error: uninitialized symbol 'page'.

mm/hugetlb.c
    2151 static
    2152 struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
    2153 		struct vm_area_struct *vma, unsigned long addr)
    2154 {
    2155 	struct page *page;

This should be "struct page *page = NULL;"


    2156 	struct mempolicy *mpol;
    2157 	gfp_t gfp_mask = htlb_alloc_mask(h);
    2158 	int nid;
    2159 	nodemask_t *nodemask;
    2160 
    2161 	nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask);
    2162 	if (mpol_is_preferred_many(mpol)) {
    2163 		gfp_t gfp = gfp_mask | __GFP_NOWARN;
    2164 
    2165 		gfp &=  ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL);
    2166 		page = alloc_surplus_huge_page(h, gfp, nid, nodemask, false);
    2167 
    2168 		/* Fallback to all nodes if page==NULL */
    2169 		nodemask = NULL;
    2170 	}
    2171 
--> 2172 	if (!page)
    2173 		page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask, false);
    2174 	mpol_cond_put(mpol);
    2175 	return page;
    2176 }

regards,
dan carpenter

Re: [bug report] Merge branch 'akpm-current/current'

[Feng Tang]

Hi Dan,

On Wed, Aug 11, 2021 at 04:06:00PM +0800, Dan Carpenter wrote:
> [ I do a git show 2db9f815409f and it doesn't show that hugetlb.c was
>   modified but it the git log the merge commit is listed.  I don't
>   know git well enough to explain it.  But I think this was a merge
>   issue.  - dan ]
> 
> Hello Stephen Rothwell,
> 
> The patch 2db9f815409f: "Merge branch 'akpm-current/current'" from
> Aug 10, 2021, leads to the following
> Smatch static checker warning:
> 
> 	mm/hugetlb.c:2172 alloc_buddy_huge_page_with_mpol()
> 	error: uninitialized symbol 'page'.
> 
> mm/hugetlb.c
>     2151 static
>     2152 struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
>     2153 		struct vm_area_struct *vma, unsigned long addr)
>     2154 {
>     2155 	struct page *page;
> 
> This should be "struct page *page = NULL;"

Thanks for the report! This was also reported by Nathan Chancellor,
who gave a quick fix: https://lore.kernel.org/lkml/20210810200632.3812797-1-nathan@kernel.org/
and Andrew has taken it to the -mm tree.

Sorry for the inconvenience.

- Feng