On Fri, 27 Feb 2015 17:07:28 -0800 Danesh Petigara <dpetigara@xxxxxxxxxxxx> wrote: > On 2/27/2015 3:54 PM, Andrew Morton wrote: > > On Fri, 27 Feb 2015 15:52:56 -0800 Danesh Petigara <dpetigara@xxxxxxxxxxxx> wrote: > > > >> On 2/27/2015 1:24 PM, Andrew Morton wrote: > >>> On Tue, 24 Feb 2015 15:39:45 -0800 Danesh Petigara <dpetigara@xxxxxxxxxxxx> wrote: > >>> > >>>> The CMA aligned offset calculation is incorrect for > >>>> non-zero order_per_bit values. > >>>> > >>>> For example, if cma->order_per_bit=1, cma->base_pfn= > >>>> 0x2f800000 and align_order=12, the function returns > >>>> a value of 0x17c00 instead of 0x400. > >>>> > >>>> This patch fixes the CMA aligned offset calculation. > >>> > >>> When fixing a bug please always describe the end-user visible effects > >>> of that bug. > >>> > >>> Without that information others are unable to understand why you are > >>> recommending a -stable backport. > >>> > >> > >> Thank you for the feedback. I had no crash logs to show, nevertheless, I > >> agree that a sentence describing potential effects of the bug would've > >> helped. > > > > What was the reason for adding a cc:stable? > > > > It was added since the commit that introduced the incorrect logic > (b5be83e) was already picked up by v3.19. argh. afaict the bug will, under some conditions cause cma_alloc() to report that no suitable free area is available in the arena when in fact such regions *are* available. So it's effectively a bogus ENOMEM. Correct? If so, what are the conditions under which this will occur? This isn't hard - I want to know what the patch *does*! -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>