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| author | Aaron Lu <aaron.lu@intel.com> | 2013-11-06 08:41:31 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-12-04 10:56:58 -0800 |
| commit | 67b51f87ef941607e1e891bf477bd18df53ce6f1 (patch) | |
| tree | b4fca418f3ef838d5d09c053c72b7856b2c78213 /kernel | |
| parent | d8db1a5f3133ec936bcbaced67890f229551d24f (diff) | |
| download | lwn-67b51f87ef941607e1e891bf477bd18df53ce6f1.tar.gz lwn-67b51f87ef941607e1e891bf477bd18df53ce6f1.zip | |
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>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/power/snapshot.c | 6 |
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. */ |