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. 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 -- Damian Pietras
--- xen-4.8.3+xsa267+shim4.10.1+xsa267.orig/shim/tools/xenstore/xs.c +++ xen-4.8.3+xsa267+shim4.10.1+xsa267/shim/tools/xenstore/xs.c @@ -800,7 +800,7 @@ bool xs_watch(struct xs_handle *h, const struct iovec iov[2]; #ifdef USE_PTHREAD -#define DEFAULT_THREAD_STACKSIZE (16 * 1024) +#define DEFAULT_THREAD_STACKSIZE (32 * 1024) #define READ_THREAD_STACKSIZE \ ((DEFAULT_THREAD_STACKSIZE < PTHREAD_STACK_MIN) ? \ PTHREAD_STACK_MIN : DEFAULT_THREAD_STACKSIZE) --- xen-4.8.3+xsa267+shim4.10.1+xsa267.orig/tools/xenstore/xs.c +++ xen-4.8.3+xsa267+shim4.10.1+xsa267/tools/xenstore/xs.c @@ -725,7 +725,7 @@ bool xs_watch(struct xs_handle *h, const struct iovec iov[2]; #ifdef USE_PTHREAD -#define DEFAULT_THREAD_STACKSIZE (16 * 1024) +#define DEFAULT_THREAD_STACKSIZE (32 * 1024) #define READ_THREAD_STACKSIZE \ ((DEFAULT_THREAD_STACKSIZE < PTHREAD_STACK_MIN) ? \ PTHREAD_STACK_MIN : DEFAULT_THREAD_STACKSIZE)
