The patch titled Subject: mm,hugetlb: take hugetlb_lock before decrementing h->resv_huge_pages has been added to the -mm mm-hotfixes-unstable branch. Its filename is mmhugetlb-take-hugetlb_lock-before-decrementing-h-resv_huge_pages.patch
This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...
This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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 via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days
------------------------------------------------------ From: Rik van Riel riel@surriel.com Subject: mm,hugetlb: take hugetlb_lock before decrementing h->resv_huge_pages Date: Mon, 17 Oct 2022 20:25:05 -0400
The h->*_huge_pages counters are protected by the hugetlb_lock, but alloc_huge_page has a corner case where it can decrement the counter outside of the lock.
This could lead to a corrupted value of h->resv_huge_pages, which we have observed on our systems.
Take the hugetlb_lock before decrementing h->resv_huge_pages to avoid a potential race.
Link: https://lkml.kernel.org/r/20221017202505.0e6a4fcd@imladris.surriel.com Fixes: a88c76954804 ("mm: hugetlb: fix hugepage memory leak caused by wrong reserve count") Signed-off-by: Rik van Riel riel@surriel.com Reviewed-by: Mike Kravetz mike.kravetz@oracle.com Cc: Naoya Horiguchi n-horiguchi@ah.jp.nec.com Cc: Glen McCready gkmccready@meta.com Cc: Mike Kravetz mike.kravetz@oracle.com Cc: Muchun Song songmuchun@bytedance.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
mm/hugetlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/hugetlb.c~mmhugetlb-take-hugetlb_lock-before-decrementing-h-resv_huge_pages +++ a/mm/hugetlb.c @@ -2924,11 +2924,11 @@ struct page *alloc_huge_page(struct vm_a page = alloc_buddy_huge_page_with_mpol(h, vma, addr); if (!page) goto out_uncharge_cgroup; + spin_lock_irq(&hugetlb_lock); if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) { SetHPageRestoreReserve(page); h->resv_huge_pages--; } - spin_lock_irq(&hugetlb_lock); list_add(&page->lru, &h->hugepage_activelist); set_page_refcounted(page); /* Fall through */ _
Patches currently in -mm which might be from riel@surriel.com are
mmhugetlb-take-hugetlb_lock-before-decrementing-h-resv_huge_pages.patch