Coverity has informed:

*** CID 188251:  Error handling issues  (CHECKED_RETURN)
/criu/arch/x86/crtools.c: 196 in kdat_x86_has_ptrace_fpu_xsave_bug_child()
190             return 0;
191     }
192     #endif
193
194     static int kdat_x86_has_ptrace_fpu_xsave_bug_child(void *arg)
195     {
>>>     CID 188251:  Error handling issues  (CHECKED_RETURN)
>>>     Calling "ptrace" without checking return value (as is done elsewhere 46 out of 51 times).
196             ptrace(PTRACE_TRACEME, 0, 0, 0);
197             kill(getpid(), SIGSTOP);
198             pr_err("Continue after SIGSTOP.. Urr what?\n");
199             _exit(1);
200     }
201

Also added checks for kill() and waitpid().
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>