On 01/09/2015 07:34 PM, Dave Hansen wrote: > On 01/09/2015 10:25 AM, Michael Kerrisk (man-pages) wrote: >> On 9 January 2015 at 18:25, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote: >>> "Michael Kerrisk (man-pages)" <mtk.manpages@xxxxxxxxx> writes: >>>> From: Michael Kerrisk <mtk.manpages@xxxxxxxxx> >>>> >>>> commit fe8c7f5cbf91124987106faa3bdf0c8b955c4cf7 added two new prctl() >>>> operations, PR_MPX_ENABLE_MANAGEMENT and PR_MPX_DISABLE_MANAGEMENT. >>>> However, no checks were included to ensure that unused arguments >>>> are zero, as is done in many existing prctl()s and as should be >>>> done for all new prctl()s. This patch adds the required checks. >>> >>> This will break the existing gcc run time, which doesn't zero these >>> arguments. >> >> I'm a little lost here. Weren't these flags new in the >> as-yet-unreleased 3.19? How does gcc run-time depends on them already? > > These prctl()s have been around in some form or another for a few months > since the patches had not yet been merged in to the kernel. There is > support for them in a set of (yet unmerged) gcc patches, as well as some > tests which are only internal to Intel. > > This change will, indeed, break those internal tests as well as the gcc > patches. As far as I know, the code is not in production anywhere and > can be changed. The prctl() numbers have changed while the patches were > out of tree and it's a somewhat painful process each time it changes. > It's not impossible, just painful. So, sounds like thinks can be fixed (with mild inconvenience), and they should be fixed before 3.19 is actually released. Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- 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>