| Message ID | 52789B31.70005@intel.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
On Tuesday, November 05, 2013 03:16:01 PM Aaron Lu wrote: > 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. > > Reference: https://bugzilla.kernel.org/show_bug.cgi?id=60817 > Reported-and-tested-by: Leon Drugi <eyak@wp.pl> > Cc: stable <stable@vger.kernel.org> > Signed-off-by: Aaron Lu <aaron.lu@intel.com> > --- > kernel/power/snapshot.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c > index 98c3b34a4cff..91aa616a1f4e 100644 > --- a/kernel/power/snapshot.c > +++ b/kernel/power/snapshot.c > @@ -1402,7 +1402,8 @@ 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) > pages_highmem ? > + (count - max_size - pages_highmem) : 0; Well, what about 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. */ >
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 98c3b34a4cff..91aa616a1f4e 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -1402,7 +1402,8 @@ 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) > pages_highmem ? + (count - max_size - pages_highmem) : 0; pages = preallocate_image_memory(alloc, avail_normal); if (pages < alloc) { /* We have exhausted non-highmem pages, try highmem. */
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. Reference: https://bugzilla.kernel.org/show_bug.cgi?id=60817 Reported-and-tested-by: Leon Drugi <eyak@wp.pl> Cc: stable <stable@vger.kernel.org> Signed-off-by: Aaron Lu <aaron.lu@intel.com> --- kernel/power/snapshot.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)