Downstream-only patch from Mark Wielaard <mjw@redhat.com> to avoid a

crash in backtrace if the vDSO is not available.

Upstream, this code was removed in commit 82fd7314c7df8c5555dce02

("powerpc: Remove backtrace implementation"), so patch is not needed

there.

diff --git a/sysdeps/powerpc/powerpc64/backtrace.c b/sysdeps/powerpc/powerpc64/backtrace.c

index 37de9b5bdd73c316..0ffa7509dfa4862a 100644

--- a/sysdeps/powerpc/powerpc64/backtrace.c

+++ b/sysdeps/powerpc/powerpc64/backtrace.c

@@ -68,8 +68,9 @@ static inline bool

 is_sigtramp_address (void *nip)

 {

 #ifdef HAVE_SIGTRAMP_RT64

-  if (nip == GLRO (dl_vdso_sigtramp_rt64) ||

-      nip == GLRO (dl_vdso_sigtramp_rt64) + 4)

+  if ((nip == GLRO (dl_vdso_sigtramp_rt64) ||

+       nip == GLRO (dl_vdso_sigtramp_rt64) + 4)

+      && nip != NULL)

     return true;

 #endif

   return false;