mm: fix atomic_t overflow in vm
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
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 @@
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 allocate a new virtual
@@ -177,7 +177,7 @@
* cast `allowed' as a signed long because vm_committed_space
* sometimes has a negative value
*/
- if (atomic_read(&vm_committed_space) < (long)allowed)
+ if (atomic_long_read(&vm_committed_space) < (long)allowed)
return 0;
error:
vm_unacct_memory(pages);