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Commit 2d28e01d authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'akpm' (patches from Andrew) 

Merge misc fixes from Andrew Morton:
 "2 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  hugetlbfs: fix races and page leaks during migration
  kasan: turn off asan-stack for clang-8 and earlier
parents 6357c812 cb6acd01

fs/hugetlbfs/inode.c

+12 −0
Original line number Diff line number Diff line
@@ -859,6 +859,18 @@ static int hugetlbfs_migrate_page(struct address_space *mapping, 
	rc = migrate_huge_page_move_mapping(mapping, newpage, page);

	if (rc != MIGRATEPAGE_SUCCESS)

		return rc;



	/*

	 * page_private is subpool pointer in hugetlb pages.  Transfer to

	 * new page.  PagePrivate is not associated with page_private for

	 * hugetlb pages and can not be set here as only page_huge_active

	 * pages can be migrated.

	 */

	if (page_private(page)) {

		set_page_private(newpage, page_private(page));

		set_page_private(page, 0);

	}



	if (mode != MIGRATE_SYNC_NO_COPY)

		migrate_page_copy(newpage, page);

	else

lib/Kconfig.kasan

+22 −0
Original line number Diff line number Diff line
@@ -113,6 +113,28 @@ config KASAN_INLINE 


endchoice



config KASAN_STACK_ENABLE

	bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST

	default !(CLANG_VERSION < 90000)

	depends on KASAN

	help

	  The LLVM stack address sanitizer has a know problem that

	  causes excessive stack usage in a lot of functions, see

	  https://bugs.llvm.org/show_bug.cgi?id=38809

	  Disabling asan-stack makes it safe to run kernels build

	  with clang-8 with KASAN enabled, though it loses some of

	  the functionality.

	  This feature is always disabled when compile-testing with clang-8

	  or earlier to avoid cluttering the output in stack overflow

	  warnings, but clang-8 users can still enable it for builds without

	  CONFIG_COMPILE_TEST.  On gcc and later clang versions it is

	  assumed to always be safe to use and enabled by default.



config KASAN_STACK

	int

	default 1 if KASAN_STACK_ENABLE || CC_IS_GCC

	default 0



config KASAN_S390_4_LEVEL_PAGING

	bool "KASan: use 4-level paging"

	depends on KASAN && S390

mm/hugetlb.c

+13 −3
Original line number Diff line number Diff line
@@ -3624,7 +3624,6 @@ static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, 
	copy_user_huge_page(new_page, old_page, address, vma,

			    pages_per_huge_page(h));

	__SetPageUptodate(new_page);

	set_page_huge_active(new_page);



	mmu_notifier_range_init(&range, mm, haddr, haddr + huge_page_size(h));

	mmu_notifier_invalidate_range_start(&range);
@@ -3645,6 +3644,7 @@ static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, 
				make_huge_pte(vma, new_page, 1));

		page_remove_rmap(old_page, true);

		hugepage_add_new_anon_rmap(new_page, vma, haddr);

		set_page_huge_active(new_page);

		/* Make the old page be freed below */

		new_page = old_page;

	}
@@ -3729,6 +3729,7 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm, 
	pte_t new_pte;

	spinlock_t *ptl;

	unsigned long haddr = address & huge_page_mask(h);

	bool new_page = false;



	/*

	 * Currently, we are forced to kill the process in the event the
@@ -3790,7 +3791,7 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm, 
		}

		clear_huge_page(page, address, pages_per_huge_page(h));

		__SetPageUptodate(page);

		set_page_huge_active(page);

		new_page = true;



		if (vma->vm_flags & VM_MAYSHARE) {

			int err = huge_add_to_page_cache(page, mapping, idx);
@@ -3861,6 +3862,15 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm, 
	}



	spin_unlock(ptl);



	/*

	 * Only make newly allocated pages active.  Existing pages found

	 * in the pagecache could be !page_huge_active() if they have been

	 * isolated for migration.

	 */

	if (new_page)

		set_page_huge_active(page);



	unlock_page(page);

out:

	return ret;
@@ -4095,7 +4105,6 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, 
	 * the set_pte_at() write.

	 */

	__SetPageUptodate(page);

	set_page_huge_active(page);



	mapping = dst_vma->vm_file->f_mapping;

	idx = vma_hugecache_offset(h, dst_vma, dst_addr);
@@ -4163,6 +4172,7 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, 
	update_mmu_cache(dst_vma, dst_addr, dst_pte);



	spin_unlock(ptl);

	set_page_huge_active(page);

	if (vm_shared)

		unlock_page(page);

	ret = 0;

mm/migrate.c

+11 −0
Original line number Diff line number Diff line
@@ -1315,6 +1315,16 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, 
		lock_page(hpage);

	}



	/*

	 * Check for pages which are in the process of being freed.  Without

	 * page_mapping() set, hugetlbfs specific move page routine will not

	 * be called and we could leak usage counts for subpools.

	 */

	if (page_private(hpage) && !page_mapping(hpage)) {

		rc = -EBUSY;

		goto out_unlock;

	}



	if (PageAnon(hpage))

		anon_vma = page_get_anon_vma(hpage);
@@ -1345,6 +1355,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, 
		put_new_page = NULL;

	}



out_unlock:

	unlock_page(hpage);

out:

	if (rc != -EAGAIN)

scripts/Makefile.kasan

+1 −1
Original line number Diff line number Diff line
@@ -26,7 +26,7 @@ else 
	CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \

	 $(call cc-param,asan-globals=1) \

	 $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \

	 $(call cc-param,asan-stack=1) \

	 $(call cc-param,asan-stack=$(CONFIG_KASAN_STACK)) \

	 $(call cc-param,asan-use-after-scope=1) \

	 $(call cc-param,asan-instrument-allocas=1)

endif