Commit 79dc4fc2 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'x86-urgent-2022-05-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull x86 fix from Thomas Gleixner:
 "A single fix for the handling of unpopulated sub-pmd spaces.

  The copy & pasta from the corresponding s390 code screwed up the
  address calculation for marking the sub-pmd ranges via memset by
  omitting the ALIGN_DOWN() to calculate the proper start address.

  It's a mystery why this code is not generic and shared because there
  is nothing architecture specific in there, but that's too intrusive
  for a backportable fix"

* tag 'x86-urgent-2022-05-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Fix marking of unused sub-pmd ranges
parents 990e798d 280abe14

arch/x86/mm/init_64.c

+3 −2
Original line number Diff line number Diff line
@@ -902,6 +902,8 @@ static void __meminit vmemmap_use_sub_pmd(unsigned long start, unsigned long end 


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_sub_pmd(unsigned long start, unsigned long 
	 * 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