Re: [Qemu-devel] [PATCH for-1.4] libqtest: Wait for the right child PID after killing QEMU

[Anthony Liguori]

Andreas Färber <address@hidden> writes:

> Am 28.01.2013 19:15, schrieb Eduardo Habkost:
>> When running "make check" with gcov enabled, we get the following
>> message:
>> 
>>    hw/tmp105.gcda:cannot open data file, assuming not executed
>> 
>> The problem happens because:
>> 
>>  * tmp105-test exits before QEMU exits, because waitpid() at
>>    qtest_quit() fails;
>>  * waitpid() fails because there's another process already
>>    waiting for the QEMU process;
>>  * The process that is already waiting for QEMU is the child created by
>>    qtest_init() to run system();
>>  * qtest_quit() is incorrectly waiting for the QEMU PID directly instead
>>    of the child created by qtest_init().
>> 
>> This fixes the problem by sending SIGTERM to QEMU, but waiting for the
>> child process created by qtest_init() (that exits immediately after QEMU
>> exits).
>> 
>> Reported-by: Andreas Färber <address@hidden>
>> Signed-off-by: Eduardo Habkost <address@hidden>
>
> Thanks. Still need to test this...
>
> Anthony, might this by any chance fix your sparc 100% CPU issue?

I don't see how.  How would this impact the QEMU process?

Regards,

Anthony Liguori


>
> Andreas
>
>> ---
>>  tests/libqtest.c | 7 +++++--
>>  1 file changed, 5 insertions(+), 2 deletions(-)
>> 
>> diff --git a/tests/libqtest.c b/tests/libqtest.c
>> index 913fa05..762dec4 100644
>> --- a/tests/libqtest.c
>> +++ b/tests/libqtest.c
>> @@ -39,7 +39,8 @@ struct QTestState
>>      int qmp_fd;
>>      bool irq_level[MAX_IRQ];
>>      GString *rx;
>> -    gchar *pid_file;
>> +    gchar *pid_file; /* QEMU PID file */
>> +    int child_pid;   /* Child process created to execute QEMU */
>>      char *socket_path, *qmp_socket_path;
>>  };
>>  
>> @@ -144,6 +145,7 @@ QTestState *qtest_init(const char *extra_args)
>>  
>>      s->rx = g_string_new("");
>>      s->pid_file = pid_file;
>> +    s->child_pid = pid;
>>      for (i = 0; i < MAX_IRQ; i++) {
>>          s->irq_level[i] = false;
>>      }
>> @@ -165,8 +167,9 @@ void qtest_quit(QTestState *s)
>>  
>>      pid_t pid = qtest_qemu_pid(s);
>>      if (pid != -1) {
>> +        /* kill QEMU, but wait for the child created by us to run system() 
>> */
>>          kill(pid, SIGTERM);
>> -        waitpid(pid, &status, 0);
>> +        waitpid(s->child_pid, &status, 0);
>>      }
>>  
>>      unlink(s->pid_file);
>> 
>
>
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