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Revert "s390/mm: Allow large pages for KASAN shadow mapping"

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This reverts commit ff123eb774.

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 d8073dc6bc ("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: ff123eb774 ("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>
This commit is contained in:
Vasily Gorbik 2024-11-29 01:07:01 +01:00 committed by Heiko Carstens
parent 889221c4d7
commit cc00550b2a
1 changed files with 1 additions and 11 deletions
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12
arch/s390/boot/vmem.c
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@ -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,