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authorAaron Lu <aaron.lu@intel.com>2013-11-06 08:41:31 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-12-04 10:50:31 -0800
commit7094547c201149598a2bd90ef7f04d477dffae1b (patch)
tree1322f341512653df7c5a93b4a26fed9aaf24217f
parent3ccb527f871a225b8eada036d24d41c59e40a2e4 (diff)
PM / hibernate: Avoid overflow in hibernate_preallocate_memory()
commit fd432b9f8c7c88428a4635b9f5a9c6e174df6e36 upstream. When system has a lot of highmem (e.g. 16GiB using a 32 bits kernel), the code to calculate how much memory we need to preallocate in normal zone may cause overflow. As Leon has analysed: It looks that during computing 'alloc' variable there is overflow: alloc = (3943404 - 1970542) - 1978280 = -5418 (signed) And this function goes to err_out. Fix this by avoiding that overflow. References: https://bugzilla.kernel.org/show_bug.cgi?id=60817 Reported-and-tested-by: Leon Drugi <eyak@wp.pl> Signed-off-by: Aaron Lu <aaron.lu@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--kernel/power/snapshot.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 0de28576807d..91c04f16e79c 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1398,7 +1398,11 @@ int hibernate_preallocate_memory(void)
* highmem and non-highmem zones separately.
*/
pages_highmem = preallocate_image_highmem(highmem / 2);
- alloc = (count - max_size) - pages_highmem;
+ alloc = count - max_size;
+ if (alloc > pages_highmem)
+ alloc -= pages_highmem;
+ else
+ alloc = 0;
pages = preallocate_image_memory(alloc, avail_normal);
if (pages < alloc) {
/* We have exhausted non-highmem pages, try highmem. */