On Wed, Aug 11, 2021 at 04:06:18AM +0100, Matthew Wilcox wrote:
> On Tue, Aug 10, 2021 at 10:22:37PM -0400, Qian Cai wrote:
> > and the page->lru has an address fffffffffffffffc for some reasons. Does it sound like some error code
> > had not been handled properly and had been propagated here instead? I tried reverting a few recent
> > commits for mm/hugetlb.c and mm/memblock.c without luck so far.
>
> Yes, ff..fc is going to be at offset 8 from the actual address, so
> that's -12 and -12 is ...
>
> #define ENOMEM 12 /* Out of memory */
>
> so something's returning ERR_PTR(-ENOMEM) instead of NULL.
page is not initialized in alloc_buddy_huge_page_with_mpol() and after
commit 2cfa8b23744f ("mm-hugetlb-add-support-for-mempolicy-mpol_preferred_many-fix") we have
struct page *page;
...
if (mpol_is_preferred_many(mpol)) {
gfp_t gfp = gfp_mask | __GFP_NOWARN;
gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL);
page = alloc_surplus_huge_page(h, gfp, nid, nodemask, false);
/* Fallback to all nodes if page==NULL */
nodemask = NULL;
}
if (!page)
page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask, false
mpol_cond_put(mpol);
return page;
so for !mpol_is_preferred_many() we return an uninitialized variable.
This should fix it:
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 008662083fec..6337697f7ee4 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2152,7 +2152,7 @@ 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;
--
Sincerely yours,
Mike.
