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Problem Report 1370 Details

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Report 1370 Actions

    Problem Report Number 1370
    Submitter's Classification Test Suite problem
    State Resolved
    Resolution Test Suite Deficiency (TSD)
    Problem Resolution ID TSD.X.0652
    Raised 1970-01-01 08:00
    Updated 2003-03-13 08:00
    Published 1996-11-21 08:00
    Product Standard Internationalised System Calls and Libraries Extended (UNIX 95)
    Certification Program The Open Brand certification program
    Test Suite VSU version 4.1.0
    Test Identification Base/sigaction 14,19
    Problem Summary TSD4U.00165 This test may fail intermittently on some implementations.
    Problem Text
    Both of these tests are highly timing dependent and as a result may fail on an
    intermittent basis.

    In both sigaction #14 and sigaction #19, the tests set up the action for the
    SIGCHLD signal. In the case of sigaction #14, the test sets the signal handler
    to SIG_DFL and also sets the SA_NOCLDWAIT flag. For sigaction #19, the signal
    handler is set to SIG_IGN.

    After calling sigaction(), the tests fork a child that exits and then fork a
    child that sleeps. In all except for the first test case in sigaction #14
    (wait()), this sleep is for 1 second. The tests then call time(&time1), then
    one of wait(), waitpid(), wait3(), or waitid() expecting a return of -1 and
    errno set to ECHILD. The tests then call time(&time2), expecting that
    time2-time1 >= 1. If the value returned is less than one, the tests fail on
    the assumption that the wait function under test did not block.

    The sleep(1) in the child does not guarantee that the parent will have time to
    block for a full second. The calls to the wait() functions are returning the
    expected results, however depending on what the scheduler does, the timing can
    fall on either side of the tested time interval. Increasing the sleep time
    will more likely guarantee that the assertion under test will not be subject
    to implementation specific timing/scheduling differences. The real problem
    however, is that as the tests are currently written, there is a race condition
    between the parent and child and as such there is no guarantee that the
    the call time(&time1) will occur before the sleep(). A way to guarantee that
    this will occur is to move the first call to time() to before the call to
    fork().
    Test Output
    TEST CASE: sigaction

    TEST PURPOSE #14
    After a call to int sigaction(int sig, const struct
    sigaction *act, struct sigaction *oact) when
    SA_NOCLDWAIT is set in the sa_flags member of the
    structure pointed to by act and sig is SIGCHLD, if the
    calling process subsequently waits for its children
    and the process has no unwaited for children that were
    transformed into zombie processes it shall block until
    all its children terminate, and wait(), wait3(),
    waitid(), and waitpid() shall fail and set errno to
    ECHLD.
    PREP: Set up action for SIGCHLD
    PREP: fork() a child that exits
    PREP: fork() a child that sleeps
    TEST: wait() returns -1 and errno = ECHILD
    TEST: wait() blocks until child exits
    PREP: fork() a child that sleeps
    TEST: waitpid() returns -1 and errno = ECHILD
    TEST: waitpid() blocks until child exits
    PREP: fork() a child that sleeps
    TEST: wait3() returns -1 and errno = ECHILD
    TEST: wait3() blocks until child exits
    PREP: fork() a child that sleeps
    TEST: waitid() returns -1 and errno = ECHILD
    TEST: waitid() blocks until child exits
    ERROR: waitid() did not block
    14 FAIL

    TEST PURPOSE #19
    After a call to int sigaction(int sig, const struct
    sigaction *act, struct sigaction *oact) when the
    action for SIGCHLD is set to SIG_IGN if the calling
    process subsequently waits for its children and the
    process has no unwaited for children that were
    transformed into zombie processes it shall block until
    all its children terminate, and wait(), wait3(),
    waitid(), and waitpid() shall fail and set errno to
    ECHILD.
    PREP: Set SIG_IGN for SIGCHLD
    PREP: fork() a child that exits
    PREP: fork() a child that sleeps
    TEST: wait() returns -1 and errno = ECHILD
    TEST: wait() blocks until child exits
    PREP: fork() a child that sleeps
    TEST: waitpid() returns -1 and errno = ECHILD
    TEST: waitpid() blocks until child exits
    PREP: fork() a child that sleeps
    TEST: wait3() returns -1 and errno = ECHILD
    TEST: wait3() blocks until child exits
    ERROR: wait3() did not block
    PREP: fork() a child that sleeps
    TEST: waitid() returns -1 and errno = ECHILD
    TEST: waitid() blocks until child exits
    19 FAIL

    Review Information

    Review Type TSMA Review
    Start Date null
    Completed null
    Status Complete
    Review Recommendation No Resolution Given
    Review Response
    We agree this is a test suite deficiency in the version(s)
    listed.

    In the future, in order for a vendor to site this TSD in
    support of a test report showing failures of these tests,
    the vendor must also provide results for these tests
    from a run in which they did not fail, so as to illustrate the
    intermittent failure documented here is in fact the problem
    encountered.

    Review Type SA Review
    Start Date null
    Completed null
    Status Complete
    Review Resolution Test Suite Deficiency (TSD)
    Review Conclusion
    This is an agreed Test Suite Deficiency.

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