Hi, On 06/28/2018 09:58 AM, Damian Pietras wrote: > I've also hit it on one of my boxes with > 4.8.3+xsa267+shim4.10.1+xsa267-1+deb9u8 > > This is related to too small stack size set for threads in XEN utils > which explicitly set it to use 16KB. Similar issue is reported here for > NTP: https://bugzilla.redhat.com/show_bug.cgi?id=1564527 > > I've recompilled the package with the attached patch to increase the > stack size from 16KB to 32KB and it works.
Thanks for doing "bug triaging"! > Technical details: > > The issue appears with modern CPU that support AVX-512 instruction set, > in my case it's Intel(R) Xeon(R) Gold 6148. More details are in this > bug report against glibc: https://bugzilla.redhat.com/show_bug.cgi?id=1 > 527887#c18 > > There was a post on xen-users acknowledging the bug that says it's > fixed in XEN 4.11: https://lists.xenproject.org/archives/html/xen-users > /2018-05/msg00034.html Following that post and what happened afterwards leads me to upstream commit 448c03b3cb "tools/xenstore: try to get minimum thread stack size for watch thread", which seems to solve this problem without hardcoding some size. Maybe this should be a nice candidate for upstream backport to stable branches, since users are buying newer hardware and otherwise cannot use Debian Stable without recompiling their Xen packages? Ian? Thanks, Hans