Messages in this thread | | | Date | Tue, 19 Jun 2012 16:00:01 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v4] mm/memblock: fix overlapping allocation when doubling reserved array |
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On Tue, 19 Jun 2012 22:35:08 +0000 "Pearson, Greg" <greg.pearson@hp.com> wrote:
> On 06/19/2012 04:14 PM, Andrew Morton wrote: > > On Mon, 18 Jun 2012 17:47:58 -0600 > > Greg Pearson <greg.pearson@hp.com> wrote: > > > >> The __alloc_memory_core_early() routine will ask memblock for a range > >> of memory then try to reserve it. If the reserved region array lacks > >> space for the new range, memblock_double_array() is called to allocate > >> more space for the array. If memblock is used to allocate memory for > >> the new array it can end up using a range that overlaps with the range > >> originally allocated in __alloc_memory_core_early(), leading to possible > >> data corruption. > > OK, but we have no information about whether it *does* lead to data > > corruption. Are there workloads which trigger this? End users who are > > experiencing problems? > > > > See, I (and others) need to work out whether this patch should be > > included in 3.5 or even earlier kernels. To do that we often need the > > developer to tell us what the impact of the bug is upon users. Please > > always include this info when fixing bugs. > > Andrew, > > I'm currently working on a prototype system that exhibits the data > corruption problem when doubling the reserved array while booting the > system. This system will be a released product in the future.
OK. I guess we can slip this fix into 3.5. Do you think it should be backported? I guess "yes", as you will probably want to run 3.4 or earlier kernels on that machine.
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