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mm/vmalloc.c: avoid endless loop under v[un]mapping improper ranges

PATCH Superseded zijun_hu 1 participant 2 messages Sep 21, 2016 – Sep 23, 2016

Subsystems (2)
Memory management vmalloc

v1 of 2 Superseded Latest is v2 →

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PATCH 5/5 mm/vmalloc.c: avoid endless loop under v[un]mapping improper ranges

From: zijun_hu <[email protected]>

fix the following bug:
- endless loop maybe happen when v[un]mapping improper ranges whose either boundary is not aligned to page

Signed-off-by zijun_hu <[email protected]>
---
 mm/vmalloc.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
mm/vmalloc.c +7 -2
index 5eeecc3..16fe957 100644
@@ -67,7 +67,7 @@ static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end)
 	do {
 		pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte);
 		WARN_ON(!pte_none(ptent) && !pte_present(ptent));
-	} while (pte++, addr += PAGE_SIZE, addr != end);
+	} while (pte++, addr += PAGE_SIZE, addr < end && addr >= PAGE_SIZE);
 }
 
 static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end)

@@ -108,6 +108,9 @@ static void vunmap_page_range(unsigned long addr, unsigned long end)
 	unsigned long next;
 
 	BUG_ON(addr >= end);
+	WARN_ON(!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(end));
+
+	addr = round_down(addr, PAGE_SIZE);
 	pgd = pgd_offset_k(addr);
 	do {
 		next = pgd_addr_end(addr, end);

@@ -139,7 +142,7 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
 			return -ENOMEM;
 		set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
 		(*nr)++;
-	} while (pte++, addr += PAGE_SIZE, addr != end);
+	} while (pte++, addr += PAGE_SIZE, addr < end);
 	return 0;
 }
 

@@ -193,6 +196,8 @@ static int vmap_page_range_noflush(unsigned long start, unsigned long end,
 	int nr = 0;
 
 	BUG_ON(addr >= end);
+	BUG_ON(!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(end));
+
 	pgd = pgd_offset_k(addr);
 	do {
 		next = pgd_addr_end(addr, end);
Signature · 1 line
1.9.1
author
#1 lore raw
Quoted 45 lines · zijun_hu

From: zijun_hu <[email protected]>

fix the following bug:
- endless loop maybe happen when v[un]mapping improper ranges whose either boundary is not aligned to page

Signed-off-by zijun_hu <[email protected]>
---
 mm/vmalloc.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
mm/vmalloc.c +5 -2
index 5eeecc3..16fe957 100644
@@ -67,7 +67,7 @@ static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end)
 	do {
 		pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte);
 		WARN_ON(!pte_none(ptent) && !pte_present(ptent));
-	} while (pte++, addr += PAGE_SIZE, addr != end);
+	} while (pte++, addr += PAGE_SIZE, addr < end && addr >= PAGE_SIZE);
 }
 
 static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end)

@@ -108,6 +108,9 @@ static void vunmap_page_range(unsigned long addr, unsigned long end)
 	unsigned long next;
 
 	BUG_ON(addr >= end);
+	WARN_ON(!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(end));
+
+	addr = round_down(addr, PAGE_SIZE);
 	pgd = pgd_offset_k(addr);
 	do {
 		next = pgd_addr_end(addr, end);

@@ -139,7 +142,7 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
 			return -ENOMEM;
 		set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
 		(*nr)++;
-	} while (pte++, addr += PAGE_SIZE, addr != end);
+	} while (pte++, addr += PAGE_SIZE, addr < end);
 	return 0;
 }

mm/vmalloc.c static int vmap_page_range_noflush(unsigned long start, unsigned long end, · line 203

Quoted 8 lines
mm/vmalloc.c +2 -0
@@ -193,6 +196,8 @@ static int vmap_page_range_noflush(unsigned long start, unsigned long end,
 	int nr = 0;
 
 	BUG_ON(addr >= end);
+	BUG_ON(!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(end));
+
 	pgd = pgd_offset_k(addr);
 	do {
 		next = pgd_addr_end(addr, end);

From: zijun_hu <[email protected]>

s/WARN_ON()/WARN_ON_ONCE()/ to reduce warning messages

Signed-off-by zijun_hu <[email protected]>
---
 mm/vmalloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
mm/vmalloc.c +1 -1
index 16fe957..e34031e 100644
@@ -108,7 +108,7 @@ static void vunmap_page_range(unsigned long addr, unsigned long end)
 	unsigned long next;
 
 	BUG_ON(addr >= end);
-	WARN_ON(!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(end));
+	WARN_ON_ONCE(!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(end));
 
 	addr = round_down(addr, PAGE_SIZE);
 	pgd = pgd_offset_k(addr);
Signature · 1 line
1.9.1