[PATCH] missing NULL pointer check in pte_alloc_one.

[PATCH] missing NULL pointer check in pte_alloc_one.

[Martin Schwidefsky]

Hi,
just found an small bug in pgalloc for s390*. Comparing notes
with other architectures I found that pte_alloc_one is sick for
alpha and sparc64 as well. See patch below.

blue skies,
  Martin.

ChangeLog:
Add NULL pointer check to pte_alloc_one for alpha, s390 and sparc64.

diffstat:
 asm-alpha/pgalloc.h   |    5 ++++-
 asm-s390/pgalloc.h    |    5 ++++-
 asm-sparc64/pgalloc.h |   10 +++++++++-
 3 files changed, 17 insertions(+), 3 deletions(-)

diff -urN linux-2.6/include/asm-alpha/pgalloc.h linux-2.6-pgalloc/include/asm-alpha/pgalloc.h
--- linux-2.6/include/asm-alpha/pgalloc.h	Thu Mar 11 03:55:20 2004
+++ linux-2.6-pgalloc/include/asm-alpha/pgalloc.h	Thu Apr  1 20:48:54 2004
@@ -63,7 +63,10 @@
 static inline struct page *
 pte_alloc_one(struct mm_struct *mm, unsigned long addr)
 {
-	return virt_to_page(pte_alloc_one_kernel(mm, addr));
+	pte_t *pte = pte_alloc_one_kernel(mm, addr);
+	if (pte)
+		return virt_to_page(pte);
+	return 0;
 }
 
 static inline void
diff -urN linux-2.6/include/asm-s390/pgalloc.h linux-2.6-pgalloc/include/asm-s390/pgalloc.h
--- linux-2.6/include/asm-s390/pgalloc.h	Thu Mar 11 03:55:34 2004
+++ linux-2.6-pgalloc/include/asm-s390/pgalloc.h	Thu Apr  1 20:48:54 2004
@@ -139,7 +139,10 @@
 static inline struct page *
 pte_alloc_one(struct mm_struct *mm, unsigned long vmaddr)
 {
-	return virt_to_page(pte_alloc_one_kernel(mm, vmaddr));
+	pte_t *pte = pte_alloc_one_kernel(mm, vmaddr);
+	if (pte)
+		return virt_to_page(pte_alloc_one_kernel(mm, vmaddr));
+	return 0;
 }
 
 static inline void pte_free_kernel(pte_t *pte)
diff -urN linux-2.6/include/asm-sparc64/pgalloc.h linux-2.6-pgalloc/include/asm-sparc64/pgalloc.h
--- linux-2.6/include/asm-sparc64/pgalloc.h	Thu Apr  1 15:23:23 2004
+++ linux-2.6-pgalloc/include/asm-sparc64/pgalloc.h	Thu Apr  1 20:48:54 2004
@@ -189,7 +189,15 @@
 	pmd_populate_kernel(MM,PMD,page_address(PTE_PAGE))
 
 extern pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address);
-#define pte_alloc_one(MM,ADDR)	virt_to_page(pte_alloc_one_kernel(MM,ADDR))
+
+static inline struct page *
+pte_alloc_one(struct mm_struct *mm, unsigned long addr)
+{
+	pte_t *pte = pte_alloc_one_kernel(mm, addr);
+	if (pte)
+		return virt_to_page(pte);
+	return 0;
+}
 
 static __inline__ pte_t *pte_alloc_one_fast(struct mm_struct *mm, unsigned long address)
 {

Re: [PATCH] missing NULL pointer check in pte_alloc_one.

[Martin Schwidefsky]

Hi Andrew,
stupid cut-copy-paste error. I fixed the problem for alpha and sparc64
but I broke s390. pte_alloc_one shouldn't allocate two pages, return one
and forget the other without freeing it...

blue skies,
  Martin.

diff -urN linux-2.6/include/asm-s390/pgalloc.h linux-2.6-pgalloc/include/asm-s390/pgalloc.h
--- linux-2.6/include/asm-s390/pgalloc.h	Wed Apr  7 18:17:19 2004
+++ linux-2.6-pgalloc/include/asm-s390/pgalloc.h	Wed Apr  7 18:16:50 2004
@@ -141,7 +141,7 @@
 {
 	pte_t *pte = pte_alloc_one_kernel(mm, vmaddr);
 	if (pte)
-		return virt_to_page(pte_alloc_one_kernel(mm, vmaddr));
+		return virt_to_page(pte);
 	return 0;
 }