The request PTRACE_SINGLEBLOCK was introduced in Linux 3.15. Thus the ptrace call
will fail on older kernels.
Thus the test is now testing PTRACE_SINGLEBLOCK with data argument pointing to a
buffer on stack which is assumed to fail. If the request would be interpreted as
PTRACE_GETREGS, then the ptrace call will not fail and the regs are written to buf.
If we run with a kernel with support for PTRACE_SINGLEBLOCK a ptrace call with
data=NULL, returns zero with no error. If we run with a kernel without support for
PTRACE_SINGLEBLOCK a ptrace call with data=NULL reports an error.
In the latter case, the test is just continuing with PTRACE_CONT.
ChangeLog:
* sysdeps/unix/sysv/linux/s390/tst-ptrace-singleblock.c:
Support running on kernels without PTRACE_SINGLEBLOCK.
2c80445787