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/nommu.c b/mm/nommu.c
index ef8c62c..dca93fc 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -39,7 +39,7 @@
unsigned long max_mapnr;
unsigned long num_physpages;
unsigned long askedalloc, realalloc;
-atomic_t vm_committed_space = ATOMIC_INIT(0);
+atomic_long_t vm_committed_space = ATOMIC_LONG_INIT(0);
int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
int sysctl_overcommit_ratio = 50; /* default is 50% */
int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
@@ -1410,7 +1410,7 @@
* 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);