From cc00550b2ae7ab1c7c56669fc004a13d880aaf0a Mon Sep 17 00:00:00 2001 From: Vasily Gorbik Date: Fri, 29 Nov 2024 01:07:01 +0100 Subject: [PATCH] Revert "s390/mm: Allow large pages for KASAN shadow mapping" This reverts commit ff123eb7741638d55abf82fac090bb3a543c1e74. Allowing large pages for KASAN shadow mappings isn't inherently wrong, but adding POPULATE_KASAN_MAP_SHADOW to large_allowed() exposes an issue in can_large_pud() and can_large_pmd(). Since commit d8073dc6bc04 ("s390/mm: Allow large pages only for aligned physical addresses"), both can_large_pud() and can_large_pmd() call _pa() to check if large page physical addresses are aligned. However, _pa() has a side effect: it allocates memory in POPULATE_KASAN_MAP_SHADOW mode. This results in massive memory leaks. The proper fix would be to address both large_allowed() and _pa()'s side effects, but for now, revert this change to avoid the leaks. Fixes: ff123eb77416 ("s390/mm: Allow large pages for KASAN shadow mapping") Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens --- arch/s390/boot/vmem.c | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-) diff --git a/arch/s390/boot/vmem.c b/arch/s390/boot/vmem.c index 8476b6f965a9..145035f84a0e 100644 --- a/arch/s390/boot/vmem.c +++ b/arch/s390/boot/vmem.c @@ -264,17 +264,7 @@ static unsigned long _pa(unsigned long addr, unsigned long size, enum populate_m static bool large_allowed(enum populate_mode mode) { - switch (mode) { - case POPULATE_DIRECT: - case POPULATE_IDENTITY: - case POPULATE_KERNEL: -#ifdef CONFIG_KASAN - case POPULATE_KASAN_MAP_SHADOW: -#endif - return true; - default: - return false; - } + return (mode == POPULATE_DIRECT) || (mode == POPULATE_IDENTITY) || (mode == POPULATE_KERNEL); } static bool can_large_pud(pud_t *pu_dir, unsigned long addr, unsigned long end,