[PATCH 5.15 066/102] x86/mm: Fix marking of unused sub-pmd ranges

Greg Kroah-Hartman
2022-05-16T20:07:11Z

From: Adrian-Ken Rueegsegger <ken@codelabs.ch>

commit 280abe14b6e0a38de9cc86fe6a019523aadd8f70 upstream.

The unused part precedes the new range spanned by the start, end parameters
of vmemmap_use_new_sub_pmd(). This means it actually goes from
ALIGN_DOWN(start, PMD_SIZE) up to start.

Use the correct address when applying the mark using memset.

Fixes: 8d400913c231 ("x86/vmemmap: handle unpopulated sub-pmd ranges")
Signed-off-by: Adrian-Ken Rueegsegger <ken@codelabs.ch>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220509090637.24152-2-ken@codelabs.ch
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/mm/init_64.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -902,6 +902,8 @@ static void __meminit vmemmap_use_sub_pm

static void __meminit vmemmap_use_new_sub_pmd(unsigned long start, unsigned long end)
{
+ const unsigned long page = ALIGN_DOWN(start, PMD_SIZE);
+
vmemmap_flush_unused_pmd();

/*
@@ -914,8 +916,7 @@ static void __meminit vmemmap_use_new_su
* Mark with PAGE_UNUSED the unused parts of the new memmap range
*/
if (!IS_ALIGNED(start, PMD_SIZE))
- memset((void *)start, PAGE_UNUSED,
- start - ALIGN_DOWN(start, PMD_SIZE));
+ memset((void *)page, PAGE_UNUSED, start - page);

/*
* We want to avoid memset(PAGE_UNUSED) when populating the vmemmap of