From: Aaron Lu <aaron.lu@intel.com>
Date: Wed, 6 Nov 2013 00:41:31 +0000 (+0800)
Subject: PM / hibernate: Avoid overflow in hibernate_preallocate_memory()
X-Git-Tag: v3.2.54~154
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=103ebb406f8ddb3008848d6a243299e5b7ddf2f3;p=pandora-kernel.git

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: Ben Hutchings <ben@decadent.org.uk>
---

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