Hi Jan,

Jan Kiszka wrote:
Hi all,

fiddling with latest Xenomai trunk and 2.3.x on one of our robots (there
is still a bug in trunk /wrt broken timeouts of rt_dev_read on
xeno_16550A - different issue...), I ran into a weird behaviour of
rtcanrecv:

I have a continuous stream of a few thousand packets/s towards the
robot. When I start up two "rtcanrecv rtcan0 -p1000" instances (or one +
our own receiver application), the second one causes a Linux lock-up.
Sometimes this happens during startup of the second rtcanrecv, but at
latest on its termination. Other RT tasks are still running. I can
resolve the lock-up by pulling the CAN cable, everyone is fine
afterwards and can be cleaned up. I played with quite a few combinations
of recent ipipe patches and Xenomai revisions (even back to #1084 in
v2.3.x), no noticeable difference.

Seems like I have to take a closer look - once time permits and the
robot is available. So any ideas or attempts to reproduce this are
welcome, current .config attached (no magic knob found there yet).

I will try to reporduce the problem a.s.a.p.

Jan


PS: Wolfgang, any objections against "decoupling" -v from -p and
lowering the receiver priority to 0?

No, -v with -p looks like a bug anyway. And does it make sense to define an option for the task priority?


Index: src/utils/can/rtcanrecv.c
===================================================================
--- src/utils/can/rtcanrecv.c   (revision 2146)
+++ src/utils/can/rtcanrecv.c   (working copy)
@@ -192,6 +192,7 @@ int main(int argc, char **argv)

        case 'p':
            print = strtoul(optarg, NULL, 0);
+           break;

        case 'v':
            verbose = 1;
@@ -312,7 +313,7 @@ int main(int argc, char **argv)
     }

     snprintf(name, sizeof(name), "rtcanrecv-%d", getpid());
-    ret = rt_task_shadow(&rt_task_desc, name, 1, 0);
+    ret = rt_task_shadow(&rt_task_desc, name, 0, 0);
     if (ret) {
        fprintf(stderr, "rt_task_shadow: %s\n", strerror(-ret));
        goto failure;


Wolfgang.

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