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Groups > linux.kernel > #1702474

[v4 12/15] mm: explicitly zero pagetable memory

From Pavel Tatashin <pasha.tatashin@oracle.com>
Newsgroups linux.kernel
Subject [v4 12/15] mm: explicitly zero pagetable memory
Date 2017-08-02 22:50 +0200
Message-ID <ua8KC-6uU-19@gated-at.bofh.it> (permalink)
References <ua8AW-6r3-21@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Soon vmemmap_alloc_block() will no longer zero the block, so zero memory
at its call sites for everything except struct pages.  Struct page memory
is zero'd by struct page initialization.

Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
---
 mm/sparse-vmemmap.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index c50b1a14d55e..d40c721ab19f 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -191,6 +191,7 @@ pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node)
 		void *p = vmemmap_alloc_block(PAGE_SIZE, node);
 		if (!p)
 			return NULL;
+		memset(p, 0, PAGE_SIZE);
 		pmd_populate_kernel(&init_mm, pmd, p);
 	}
 	return pmd;
@@ -203,6 +204,7 @@ pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node)
 		void *p = vmemmap_alloc_block(PAGE_SIZE, node);
 		if (!p)
 			return NULL;
+		memset(p, 0, PAGE_SIZE);
 		pud_populate(&init_mm, pud, p);
 	}
 	return pud;
@@ -215,6 +217,7 @@ p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node)
 		void *p = vmemmap_alloc_block(PAGE_SIZE, node);
 		if (!p)
 			return NULL;
+		memset(p, 0, PAGE_SIZE);
 		p4d_populate(&init_mm, p4d, p);
 	}
 	return p4d;
@@ -227,6 +230,7 @@ pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
 		void *p = vmemmap_alloc_block(PAGE_SIZE, node);
 		if (!p)
 			return NULL;
+		memset(p, 0, PAGE_SIZE);
 		pgd_populate(&init_mm, pgd, p);
 	}
 	return pgd;
-- 
2.13.3

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Thread

[v4 00/15] complete deferred page initialization Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:40 +0200
  [v4 14/15] mm: optimize early system hash allocations Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:40 +0200
  [v4 03/15] sparc64/mm: setting fields in deferred pages Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 06/15] sparc64: simplify vmemmap_populate Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 01/15] x86/mm: reserve only exiting low pages Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 02/15] x86/mm: setting fields in deferred pages Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 15/15] mm: debug for raw alloctor Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 09/15] sparc64: optimized struct page zeroing Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 12/15] mm: explicitly zero pagetable memory Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 10/15] x86/kasan: explicitly zero kasan shadow memory Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 04/15] mm: discard memblock data later Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 08/15] mm: zero struct pages during initialization Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 11/15] arm64/kasan: explicitly zero kasan shadow memory Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 07/15] mm: defining memblock_virt_alloc_try_nid_raw Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 05/15] mm: don't accessed uninitialized struct pages Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200

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