Messages in this thread | | | Subject | Re: [PATCH] hugetlb: Fix __prep_compound_gigantic_page page flag setting | From | Muchun Song <> | Date | Sun, 20 Nov 2022 12:03:52 +0800 |
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> On Nov 19, 2022, at 03:52, Mike Kravetz <mike.kravetz@oracle.com> wrote: > > Commit 2b21624fc232 ("hugetlb: freeze allocated pages before creating > hugetlb pages") changed the order page flags were cleared and set in the > head page. It moved the __ClearPageReserved after __SetPageHead. > However, there is a check to make sure __ClearPageReserved is never > done on a head page. If CONFIG_DEBUG_VM_PGFLAGS is enabled, the > following BUG will be hit when creating a hugetlb gigantic page: > > page dumped because: VM_BUG_ON_PAGE(1 && PageCompound(page)) > ------------[ cut here ]------------ > kernel BUG at include/linux/page-flags.h:500! > Call Trace will differ depending on whether hugetlb page is created > at boot time or run time. > > Make sure to __ClearPageReserved BEFORE __SetPageHead. > > Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > Fixes: 2b21624fc232 ("hugetlb: freeze allocated pages before creating hugetlb pages") > Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Thanks.
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