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Re: [PATCH] mm: Fix atomic_t overflow in vm

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[view original message]
From: Alan Cox
Subject: [PATCH] mm: Fix atomic_t overflow in vm
Date: Wednesday, May 14, 2008 - 2:33 pm

From: Alan Cox <alan@redhat.com>

The atomic_t type is 32bit but a 64bit system can have more than 2^32
pages of virtual address space available. Without this we overflow on
ludicrously large mappings
---

 fs/proc/proc_misc.c  |    2 +-
 include/linux/mman.h |    4 ++--
 mm/mmap.c            |    4 ++--
 mm/nommu.c           |    4 ++--
 mm/swap.c            |    4 ++--
 5 files changed, 9 insertions(+), 9 deletions(-)


diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c
index 74a323d..32dc14c 100644
--- a/fs/proc/proc_misc.c
+++ b/fs/proc/proc_misc.c
@@ -139,7 +139,7 @@ static int meminfo_read_proc(char *page, char **start, off_t off,
 #define K(x) ((x) << (PAGE_SHIFT - 10))
 	si_meminfo(&i);
 	si_swapinfo(&i);
-	committed = atomic_read(&vm_committed_space);
+	committed = atomic_long_read(&vm_committed_space);
 	allowed = ((totalram_pages - hugetlb_total_pages())
 		* sysctl_overcommit_ratio / 100) + total_swap_pages;
 
diff --git a/include/linux/mman.h b/include/linux/mman.h
index 87920a0..dab8892 100644
--- a/include/linux/mman.h
+++ b/include/linux/mman.h
@@ -17,14 +17,14 @@
 
 extern int sysctl_overcommit_memory;
 extern int sysctl_overcommit_ratio;
-extern atomic_t vm_committed_space;
+extern atomic_long_t vm_committed_space;
 
 #ifdef CONFIG_SMP
 extern void vm_acct_memory(long pages);
 #else
 static inline void vm_acct_memory(long pages)
 {
-	atomic_add(pages, &vm_committed_space);
+	atomic_long_add(pages, &vm_committed_space);
 }
 #endif
 
diff --git a/mm/mmap.c b/mm/mmap.c
index fac6633..669499e 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -80,7 +80,7 @@ EXPORT_SYMBOL(vm_get_page_prot);
 int sysctl_overcommit_memory = OVERCOMMIT_GUESS;  /* heuristic overcommit */
 int sysctl_overcommit_ratio = 50;	/* default is 50% */
 int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
-atomic_t vm_committed_space = ATOMIC_INIT(0);
+atomic_long_t vm_committed_space = ATOMIC_LONG_INIT(0);
 
 /*
  * Check that a process has enough memory to ...
[ message continues ]
[view original message]
From: Alan Cox
Subject: Re: [PATCH] mm: Fix atomic_t overflow in vm
Date: Wednesday, May 14, 2008 - 2:37 pm

On Wed, 14 May 2008 22:33:03 +0100

Umm need to adjust the template: Add

Signed-off-by: Alan Cox <alan@redhat.com>
--


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Previous thread: [PATCH 1/2] Split list.h and move rcu-protected lists into rculist.h by Franck Bui-Huu on Wednesday, May 14, 2008 - 2:24 pm. (4 messages)

Next thread: BUG: sleeping function called from invalid context when hibernating by Sitsofe Wheeler on Wednesday, May 14, 2008 - 3:08 pm. (4 messages)