6.12-stable review patch. If anyone has any objections, please let me know.
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From: Vasily Gorbik gor@linux.ibm.com
commit cc00550b2ae7ab1c7c56669fc004a13d880aaf0a upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/s390/boot/vmem.c | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-)
--- a/arch/s390/boot/vmem.c +++ b/arch/s390/boot/vmem.c @@ -264,17 +264,7 @@ static unsigned long _pa(unsigned long a
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,