| From | Luis Henriques <> | Subject | [PATCH 3.11 127/272] PM / hibernate: Avoid overflow in hibernate_preallocate_memory() | Date | Fri, 6 Dec 2013 12:56:56 +0000 |
| |
3.11.10.1 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Aaron Lu <aaron.lu@intel.com>
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: Luis Henriques <luis.henriques@canonical.com> --- kernel/power/snapshot.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 349587b..e8d1a82 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -1399,7 +1399,11 @@ 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. */ -- 1.8.3.2
|