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Commit 80119ef5 authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds
Browse files

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: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6c7c6afb

fs/proc/proc_misc.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

include/linux/mman.h

+2 −2
Original line number Diff line number Diff line
@@ -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

mm/mmap.c

+2 −2
Original line number Diff line number Diff line
@@ -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 allocate a new virtual
@@ -177,7 +177,7 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) 
	 * 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);

mm/nommu.c

+2 −2
Original line number Diff line number Diff line
@@ -39,7 +39,7 @@ struct page *mem_map; 
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 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) 
	 * 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);

mm/swap.c

+2 −2
Original line number Diff line number Diff line
@@ -503,7 +503,7 @@ void vm_acct_memory(long pages) 
	local = &__get_cpu_var(committed_space);

	*local += pages;

	if (*local > ACCT_THRESHOLD || *local < -ACCT_THRESHOLD) {

		atomic_add(*local, &vm_committed_space);

		atomic_long_add(*local, &vm_committed_space);

		*local = 0;

	}

	preempt_enable();
@@ -520,7 +520,7 @@ static int cpu_swap_callback(struct notifier_block *nfb, 


	committed = &per_cpu(committed_space, (long)hcpu);

	if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {

		atomic_add(*committed, &vm_committed_space);

		atomic_long_add(*committed, &vm_committed_space);

		*committed = 0;

		drain_cpu_pagevecs((long)hcpu);

	}