dirtyCOW fix for 3.4.112

http://forum.armbian.com/index.php/topic/2589-dirtycow-fix-for-34112

patch/kernel/sun4i-default/dirtyCOW-fix-for-3.4.112.patch

@@ -0,0 +1,61 @@
+From 543472582a6adcef12fae4ad11da72a62f29fb74 Mon Sep 17 00:00:00 2001
+From: Sven Kayser <sk@urbanstudio.de>
+Date: Fri, 21 Oct 2016 20:59:39 +0000
+Subject: [PATCH] dirtyCOW fix for 3.4.112
+
+---
+ include/linux/mm.h |  1 +
+ mm/memory.c        | 14 ++++++++++++--
+ 2 files changed, 13 insertions(+), 2 deletions(-)
+
+diff --git a/include/linux/mm.h b/include/linux/mm.h
+index 91b4589..e089716 100644
+--- a/include/linux/mm.h
++++ b/include/linux/mm.h
+@@ -1538,6 +1538,7 @@ struct page *follow_page(struct vm_area_struct *, unsigned long address,
+ #define FOLL_MLOCK	0x40	/* mark page as mlocked */
+ #define FOLL_SPLIT	0x80	/* don't return transhuge pages, split them */
+ #define FOLL_HWPOISON	0x100	/* check page is hwpoisoned */
++#define FOLL_COW	0x200	/* internal GUP flag */
+ 
+ typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
+ 			void *data);
+diff --git a/mm/memory.c b/mm/memory.c
+index 4774579..85661b9 100644
+--- a/mm/memory.c
++++ b/mm/memory.c
+@@ -1447,6 +1447,16 @@ int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
+ }
+ EXPORT_SYMBOL_GPL(zap_vma_ptes);
+ 
++/*
++ * FOLL_FORCE can write to even unwritable pte's, but only
++ * after we've gone through a COW cycle and they are dirty.
++ */
++static inline bool can_follow_write_pte(pte_t pte, unsigned int flags)
++{
++	return pte_write(pte) ||
++		((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte));
++}
++
+ /**
+  * follow_page - look up a page descriptor from a user-virtual address
+  * @vma: vm_area_struct mapping @address
+@@ -1529,7 +1539,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
+ 	pte = *ptep;
+ 	if (!pte_present(pte))
+ 		goto no_page;
+-	if ((flags & FOLL_WRITE) && !pte_write(pte))
++	if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags))
+ 		goto unlock;
+ 
+ 	page = vm_normal_page(vma, address, pte);
+@@ -1819,7 +1829,7 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+ 				 */
+ 				if ((ret & VM_FAULT_WRITE) &&
+ 				    !(vma->vm_flags & VM_WRITE))
+-					foll_flags &= ~FOLL_WRITE;
++					foll_flags |= FOLL_COW;
+ 
+ 				cond_resched();
+ 			}

patch/kernel/sun5i-default/dirtyCOW-fix-for-3.4.112.patch

@@ -0,0 +1,61 @@
+From 543472582a6adcef12fae4ad11da72a62f29fb74 Mon Sep 17 00:00:00 2001
+From: Sven Kayser <sk@urbanstudio.de>
+Date: Fri, 21 Oct 2016 20:59:39 +0000
+Subject: [PATCH] dirtyCOW fix for 3.4.112
+
+---
+ include/linux/mm.h |  1 +
+ mm/memory.c        | 14 ++++++++++++--
+ 2 files changed, 13 insertions(+), 2 deletions(-)
+
+diff --git a/include/linux/mm.h b/include/linux/mm.h
+index 91b4589..e089716 100644
+--- a/include/linux/mm.h
++++ b/include/linux/mm.h
+@@ -1538,6 +1538,7 @@ struct page *follow_page(struct vm_area_struct *, unsigned long address,
+ #define FOLL_MLOCK	0x40	/* mark page as mlocked */
+ #define FOLL_SPLIT	0x80	/* don't return transhuge pages, split them */
+ #define FOLL_HWPOISON	0x100	/* check page is hwpoisoned */
++#define FOLL_COW	0x200	/* internal GUP flag */
+ 
+ typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
+ 			void *data);
+diff --git a/mm/memory.c b/mm/memory.c
+index 4774579..85661b9 100644
+--- a/mm/memory.c
++++ b/mm/memory.c
+@@ -1447,6 +1447,16 @@ int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
+ }
+ EXPORT_SYMBOL_GPL(zap_vma_ptes);
+ 
++/*
++ * FOLL_FORCE can write to even unwritable pte's, but only
++ * after we've gone through a COW cycle and they are dirty.
++ */
++static inline bool can_follow_write_pte(pte_t pte, unsigned int flags)
++{
++	return pte_write(pte) ||
++		((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte));
++}
++
+ /**
+  * follow_page - look up a page descriptor from a user-virtual address
+  * @vma: vm_area_struct mapping @address
+@@ -1529,7 +1539,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
+ 	pte = *ptep;
+ 	if (!pte_present(pte))
+ 		goto no_page;
+-	if ((flags & FOLL_WRITE) && !pte_write(pte))
++	if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags))
+ 		goto unlock;
+ 
+ 	page = vm_normal_page(vma, address, pte);
+@@ -1819,7 +1829,7 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+ 				 */
+ 				if ((ret & VM_FAULT_WRITE) &&
+ 				    !(vma->vm_flags & VM_WRITE))
+-					foll_flags &= ~FOLL_WRITE;
++					foll_flags |= FOLL_COW;
+ 
+ 				cond_resched();
+ 			}

patch/kernel/sun7i-default/dirtyCOW-fix-for-3.4.112.patch

@@ -0,0 +1,61 @@
+From 543472582a6adcef12fae4ad11da72a62f29fb74 Mon Sep 17 00:00:00 2001
+From: Sven Kayser <sk@urbanstudio.de>
+Date: Fri, 21 Oct 2016 20:59:39 +0000
+Subject: [PATCH] dirtyCOW fix for 3.4.112
+
+---
+ include/linux/mm.h |  1 +
+ mm/memory.c        | 14 ++++++++++++--
+ 2 files changed, 13 insertions(+), 2 deletions(-)
+
+diff --git a/include/linux/mm.h b/include/linux/mm.h
+index 91b4589..e089716 100644
+--- a/include/linux/mm.h
++++ b/include/linux/mm.h
+@@ -1538,6 +1538,7 @@ struct page *follow_page(struct vm_area_struct *, unsigned long address,
+ #define FOLL_MLOCK	0x40	/* mark page as mlocked */
+ #define FOLL_SPLIT	0x80	/* don't return transhuge pages, split them */
+ #define FOLL_HWPOISON	0x100	/* check page is hwpoisoned */
++#define FOLL_COW	0x200	/* internal GUP flag */
+ 
+ typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
+ 			void *data);
+diff --git a/mm/memory.c b/mm/memory.c
+index 4774579..85661b9 100644
+--- a/mm/memory.c
++++ b/mm/memory.c
+@@ -1447,6 +1447,16 @@ int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
+ }
+ EXPORT_SYMBOL_GPL(zap_vma_ptes);
+ 
++/*
++ * FOLL_FORCE can write to even unwritable pte's, but only
++ * after we've gone through a COW cycle and they are dirty.
++ */
++static inline bool can_follow_write_pte(pte_t pte, unsigned int flags)
++{
++	return pte_write(pte) ||
++		((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte));
++}
++
+ /**
+  * follow_page - look up a page descriptor from a user-virtual address
+  * @vma: vm_area_struct mapping @address
+@@ -1529,7 +1539,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
+ 	pte = *ptep;
+ 	if (!pte_present(pte))
+ 		goto no_page;
+-	if ((flags & FOLL_WRITE) && !pte_write(pte))
++	if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags))
+ 		goto unlock;
+ 
+ 	page = vm_normal_page(vma, address, pte);
+@@ -1819,7 +1829,7 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+ 				 */
+ 				if ((ret & VM_FAULT_WRITE) &&
+ 				    !(vma->vm_flags & VM_WRITE))
+-					foll_flags &= ~FOLL_WRITE;
++					foll_flags |= FOLL_COW;
+ 
+ 				cond_resched();
+ 			}

patch/kernel/sun8i-default/dirtyCOW-fix-for-3.4.112.patch

@@ -0,0 +1,61 @@
+From 543472582a6adcef12fae4ad11da72a62f29fb74 Mon Sep 17 00:00:00 2001
+From: Sven Kayser <sk@urbanstudio.de>
+Date: Fri, 21 Oct 2016 20:59:39 +0000
+Subject: [PATCH] dirtyCOW fix for 3.4.112
+
+---
+ include/linux/mm.h |  1 +
+ mm/memory.c        | 14 ++++++++++++--
+ 2 files changed, 13 insertions(+), 2 deletions(-)
+
+diff --git a/include/linux/mm.h b/include/linux/mm.h
+index 91b4589..e089716 100644
+--- a/include/linux/mm.h
++++ b/include/linux/mm.h
+@@ -1538,6 +1538,7 @@ struct page *follow_page(struct vm_area_struct *, unsigned long address,
+ #define FOLL_MLOCK	0x40	/* mark page as mlocked */
+ #define FOLL_SPLIT	0x80	/* don't return transhuge pages, split them */
+ #define FOLL_HWPOISON	0x100	/* check page is hwpoisoned */
++#define FOLL_COW	0x200	/* internal GUP flag */
+ 
+ typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
+ 			void *data);
+diff --git a/mm/memory.c b/mm/memory.c
+index 4774579..85661b9 100644
+--- a/mm/memory.c
++++ b/mm/memory.c
+@@ -1447,6 +1447,16 @@ int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
+ }
+ EXPORT_SYMBOL_GPL(zap_vma_ptes);
+ 
++/*
++ * FOLL_FORCE can write to even unwritable pte's, but only
++ * after we've gone through a COW cycle and they are dirty.
++ */
++static inline bool can_follow_write_pte(pte_t pte, unsigned int flags)
++{
++	return pte_write(pte) ||
++		((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte));
++}
++
+ /**
+  * follow_page - look up a page descriptor from a user-virtual address
+  * @vma: vm_area_struct mapping @address
+@@ -1529,7 +1539,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
+ 	pte = *ptep;
+ 	if (!pte_present(pte))
+ 		goto no_page;
+-	if ((flags & FOLL_WRITE) && !pte_write(pte))
++	if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags))
+ 		goto unlock;
+ 
+ 	page = vm_normal_page(vma, address, pte);
+@@ -1819,7 +1829,7 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+ 				 */
+ 				if ((ret & VM_FAULT_WRITE) &&
+ 				    !(vma->vm_flags & VM_WRITE))
+-					foll_flags &= ~FOLL_WRITE;
++					foll_flags |= FOLL_COW;
+ 
+ 				cond_resched();
+ 			}