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 <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

diff --git a/arch/s390/boot/vmem.c b/arch/s390/boot/vmem.c
index 8476b6f965a92ea3a7978b5f3bc847e020778a39..145035f84a0e3e898ff708f815b5ac54ec541860 100644 (file)
--- 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,