Patch "mm/sparsemem: Fix ARM64 boot crash when CONFIG_SPARSEMEM_EXTREME=y" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

mm/sparsemem: Fix ARM64 boot crash when CONFIG_SPARSEMEM_EXTREME=y

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mm-sparsemem-fix-arm64-boot-crash-when-config_sparsemem_extreme-y.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: "Kirill A. Shutemov" <[email protected]>
Date: Tue, 7 Nov 2017 11:33:37 +0300
Subject: mm/sparsemem: Fix ARM64 boot crash when CONFIG_SPARSEMEM_EXTREME=y

From: Kirill A. Shutemov <[email protected]>

commit 629a359bdb0e0652a8227b4ff3125431995fec6e upstream.

Since commit:

83e3c48729d9 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")

we allocate the mem_section array dynamically in sparse_memory_present_with_active_regions(), but some architectures, like arm64, don't call the routine to initialize sparsemem.

Let's move the initialization into memory_present() it should cover all architectures.

---
 mm/page_alloc.c |   10 ----------
 mm/sparse.c     |   10 ++++++++++
 2 files changed, 10 insertions(+), 10 deletions(-)

@@ -5651,16 +5651,6 @@ void __init sparse_memory_present_with_a
 	unsigned long start_pfn, end_pfn;
 	int i, this_nid;
 
-#ifdef CONFIG_SPARSEMEM_EXTREME
-	if (!mem_section) {
-		unsigned long size, align;
-
-		size = sizeof(struct mem_section) * NR_SECTION_ROOTS;
-		align = 1 << (INTERNODE_CACHE_SHIFT);
-		mem_section = memblock_virt_alloc(size, align);
-	}
-#endif
-
 	for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid)
 		memory_present(this_nid, start_pfn, end_pfn);
 }

@@ -207,6 +207,16 @@ void __init memory_present(int nid, unsi
 {
 	unsigned long pfn;
 
+#ifdef CONFIG_SPARSEMEM_EXTREME
+	if (unlikely(!mem_section)) {
+		unsigned long size, align;
+
+		size = sizeof(struct mem_section) * NR_SECTION_ROOTS;
+		align = 1 << (INTERNODE_CACHE_SHIFT);
+		mem_section = memblock_virt_alloc(size, align);
+	}
+#endif
+
 	start &= PAGE_SECTION_MASK;
 	mminit_validate_memmodel_limits(&start, &end);
 	for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/mm-sparsemem-fix-arm64-boot-crash-when-config_sparsemem_extreme-y.patch queue-4.14/x86-xen-provide-pre-built-page-tables-only-for-config_xen_pv-y-and-config_xen_pvh-y.patch queue-4.14/x86-xen-drop-5-level-paging-support-code-from-the-xen_pv-code.patch queue-4.14/x86-kasan-use-the-same-shadow-offset-for-4-and-5-level-paging.patch queue-4.14/mm-sparsemem-allocate-mem_section-at-runtime-for-config_sparsemem_extreme-y.patch queue-4.14/x86-mm-relocate-page-fault-error-codes-to-traps.h.patch