[OBV] Testsuite: Ensure interrupt-daemon-attach doesn't run forever

Message ID 20190327115023.8808-1-alan.hayward@arm.com
State New
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  • [OBV] Testsuite: Ensure interrupt-daemon-attach doesn't run forever
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Commit Message

Alan Hayward March 27, 2019, 11:50 a.m.
[Pushed because this was slowing down the Aarch64 buildbot.
 Sergio - it's probably worth checking if there are similar hanging processes on
 the other buildslave machines.]

Looking at the AArch64 buildbot, I noticed about two dozen old instances of
interrupt-daemon-attach taking up a full 100% cpu each.

If the test fails then the test binary relies on an alarm to ensure it dies
after 60 seconds.

As per the Linux man page for alarm:
  Alarms created by alarm() ... are not inherited by children created via fork.

Update the test to add an alarm in the child and also put a sleep in the
child loop so it does not constantly consume cpu.

Note I haven't managed to re-create why the test failed.  This fix will just
stop it hanging and consuming cpu when it does.

gdb/testsuite/ChangeLog:

2019-03-27  Alan Hayward  <alan.hayward@arm.com>

	* gdb.base/interrupt-daemon-attach.c (main): Add alarm and sleep
	in child.
---
 gdb/testsuite/gdb.base/interrupt-daemon-attach.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

-- 
2.20.1 (Apple Git-117)

Comments

Sergio Durigan Junior March 27, 2019, 6:44 p.m. | #1
On Wednesday, March 27 2019, Alan Hayward wrote:

> [Pushed because this was slowing down the Aarch64 buildbot.

>  Sergio - it's probably worth checking if there are similar hanging processes on

>  the other buildslave machines.]


Thanks for the heads up, Alan.

I see pending builds on the x86_64 builders (and a few more), but I'll
leave them running for now and wait.  Hopefully in a few days things
should be back to normal.

Thanks,

> Looking at the AArch64 buildbot, I noticed about two dozen old instances of

> interrupt-daemon-attach taking up a full 100% cpu each.

>

> If the test fails then the test binary relies on an alarm to ensure it dies

> after 60 seconds.

>

> As per the Linux man page for alarm:

>   Alarms created by alarm() ... are not inherited by children created via fork.

>

> Update the test to add an alarm in the child and also put a sleep in the

> child loop so it does not constantly consume cpu.

>

> Note I haven't managed to re-create why the test failed.  This fix will just

> stop it hanging and consuming cpu when it does.

>

> gdb/testsuite/ChangeLog:

>

> 2019-03-27  Alan Hayward  <alan.hayward@arm.com>

>

> 	* gdb.base/interrupt-daemon-attach.c (main): Add alarm and sleep

> 	in child.

> ---

>  gdb/testsuite/gdb.base/interrupt-daemon-attach.c | 11 +++++++++--

>  1 file changed, 9 insertions(+), 2 deletions(-)

>

> diff --git a/gdb/testsuite/gdb.base/interrupt-daemon-attach.c b/gdb/testsuite/gdb.base/interrupt-daemon-attach.c

> index 5dc84438dc..e8dddf81b4 100644

> --- a/gdb/testsuite/gdb.base/interrupt-daemon-attach.c

> +++ b/gdb/testsuite/gdb.base/interrupt-daemon-attach.c

> @@ -43,6 +43,7 @@ main ()

>        break;

>  

>      default:

> +      /* In parent process.  */

>        while (1)

>  	{

>  	  marker ();

> @@ -50,12 +51,18 @@ main ()

>  	}

>      }

>  

> +  /* In child process.  */

> +

> +  /* Alarms are not inherited by child processes. Set the alarm again to stop

> +     the test case running forever.  */

> +  alarm (60);

> +

>    /* Detach from controlling terminal.  */

>    if (setsid () == (pid_t) -1)

>      return 1;

>  

> -  for (;;)

> -    ;

> +  while (1)

> +    usleep (1000);

>  

>    return 0;

>  }

> -- 

> 2.20.1 (Apple Git-117)


-- 
Sergio
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http://sergiodj.net/

Patch

diff --git a/gdb/testsuite/gdb.base/interrupt-daemon-attach.c b/gdb/testsuite/gdb.base/interrupt-daemon-attach.c
index 5dc84438dc..e8dddf81b4 100644
--- a/gdb/testsuite/gdb.base/interrupt-daemon-attach.c
+++ b/gdb/testsuite/gdb.base/interrupt-daemon-attach.c
@@ -43,6 +43,7 @@  main ()
       break;
 
     default:
+      /* In parent process.  */
       while (1)
 	{
 	  marker ();
@@ -50,12 +51,18 @@  main ()
 	}
     }
 
+  /* In child process.  */
+
+  /* Alarms are not inherited by child processes. Set the alarm again to stop
+     the test case running forever.  */
+  alarm (60);
+
   /* Detach from controlling terminal.  */
   if (setsid () == (pid_t) -1)
     return 1;
 
-  for (;;)
-    ;
+  while (1)
+    usleep (1000);
 
   return 0;
 }