From: David Hildenbrand <david@xxxxxxxxxx> Subject: s390/vdso: don't clear PG_reserved The VDSO is part of the kernel image and therefore the struct pages are marked as reserved during boot. As we install a special mapping, the actual struct pages will never be exposed to MM via the page tables. We can therefore leave the pages marked as reserved. Link: http://lkml.kernel.org/r/20190114125903.24845-3-david@xxxxxxxxxx Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> Suggested-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Souptick Joarder <jrdr.linux@xxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/s390/kernel/vdso.c | 2 -- 1 file changed, 2 deletions(-) --- a/arch/s390/kernel/vdso.c~s390-vdso-dont-clear-pg_reserved +++ a/arch/s390/kernel/vdso.c @@ -291,7 +291,6 @@ static int __init vdso_init(void) BUG_ON(vdso32_pagelist == NULL); for (i = 0; i < vdso32_pages - 1; i++) { struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE); - ClearPageReserved(pg); get_page(pg); vdso32_pagelist[i] = pg; } @@ -309,7 +308,6 @@ static int __init vdso_init(void) BUG_ON(vdso64_pagelist == NULL); for (i = 0; i < vdso64_pages - 1; i++) { struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE); - ClearPageReserved(pg); get_page(pg); vdso64_pagelist[i] = pg; } _
