stap on syscall probe errors with "unresolved target-symbol expression: identifier"

Solution Verified - Updated -


  • stap on syscall probe errors with unresolved target-symbol expression: identifier
  • Using SystemTap to trace a syscall probe, the variables do not work and error when implementing

probe syscall.umask {
    printf("> %s[%d] %#o\n", execname(), tid(), $mask);
    printf("%s\n", task_ancestry(pid2task(tid()), 0));

probe syscall.umask.return {
    printf("< %s[%d] %o\n", execname(), tid(), $retval);


  • Red Hat Enterprise Linux 8
  • SystemTap with probe alias such as the built-in syscall family

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