diff options
| author | Mike Kravetz <mike.kravetz@oracle.com> | 2022-11-18 22:52:49 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-11-23 05:50:44 +0300 |
| commit | 7fb0728a9b005b8fc55e835529047cca15191031 (patch) | |
| tree | c39483e917b55a294de9ee4a57fbea4ea419b8a9 | |
| parent | 747c0f35f2d55de20093e992bd9fc7292193c0e6 (diff) | |
| download | linux-7fb0728a9b005b8fc55e835529047cca15191031.tar.xz | |
hugetlb: fix __prep_compound_gigantic_page page flag setting
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.
Link: https://lkml.kernel.org/r/20221118195249.178319-1-mike.kravetz@oracle.com
Fixes: 2b21624fc232 ("hugetlb: freeze allocated pages before creating hugetlb pages")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Tested-by: Tarun Sahu <tsahu@linux.ibm.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/hugetlb.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index e48f8ef45b17..f1385c3b6c96 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1800,6 +1800,7 @@ static bool __prep_compound_gigantic_page(struct page *page, unsigned int order, /* we rely on prep_new_huge_page to set the destructor */ set_compound_order(page, order); + __ClearPageReserved(page); __SetPageHead(page); for (i = 0; i < nr_pages; i++) { p = nth_page(page, i); @@ -1816,7 +1817,8 @@ static bool __prep_compound_gigantic_page(struct page *page, unsigned int order, * on the head page when they need know if put_page() is needed * after get_user_pages(). */ - __ClearPageReserved(p); + if (i != 0) /* head page cleared above */ + __ClearPageReserved(p); /* * Subtle and very unlikely * |