The patch titled Subject: kpageflags: fix wrong KPF_THP on non-huge compound pages has been removed from the -mm tree. Its filename was kpageflags-fix-wrong-kpf_thp-on-non-huge-compound-pages.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> Subject: kpageflags: fix wrong KPF_THP on non-huge compound pages KPF_THP can be set on non-huge compound pages (like slab pages or pages allocated by drivers with __GFP_COMP) because PageTransCompound only checks PG_head and PG_tail. Obviously this is a bug and breaks user space applications which look for thp via /proc/kpageflags. This patch rules out setting KPF_THP wrongly by additionally checking PageLRU on the head pages. Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> Acked-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> Acked-by: David Rientjes <rientjes@xxxxxxxxxx> Reviewed-by: Fengguang Wu <fengguang.wu@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/proc/page.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff -puN fs/proc/page.c~kpageflags-fix-wrong-kpf_thp-on-non-huge-compound-pages fs/proc/page.c --- a/fs/proc/page.c~kpageflags-fix-wrong-kpf_thp-on-non-huge-compound-pages +++ a/fs/proc/page.c @@ -115,7 +115,13 @@ u64 stable_page_flags(struct page *page) u |= 1 << KPF_COMPOUND_TAIL; if (PageHuge(page)) u |= 1 << KPF_HUGE; - else if (PageTransCompound(page)) + /* + * PageTransCompound can be true for non-huge compound pages (slab + * pages or pages allocated by drivers with __GFP_COMP) because it + * just checks PG_head/PG_tail, so we need to check PageLRU to make + * sure a given page is a thp, not a non-huge compound page. + */ + else if (PageTransCompound(page) && PageLRU(compound_trans_head(page))) u |= 1 << KPF_THP; /* _ Patches currently in -mm which might be from n-horiguchi@xxxxxxxxxxxxx are origin.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html