On Thu, 2011-06-09 at 14:42 +0200, Wolfgang Grandegger wrote:
> Hello,
>
> I just realized a problem with synchronous message passing support. When
> rt_task_send() send times out, I get the oops below from line:
>
Does this help?
diff --git a/ksrc/skins/native/task.c b/ksrc/skins/native/task.c
index b822fd0..b0e99a7 100644
--- a/ksrc/skins/native/task.c
+++ b/ksrc/skins/native/task.c
@@ -1988,21 +1988,28 @@ int rt_task_receive(RT_TASK_MCB *mcb_r, RTIME timeout)
}
/*
- * Wait on our receive slot for some client to enqueue itself
- * in our send queue.
+ * We loop to care for spurious wakeups, in case the
+ * client times out before we unblock.
*/
- info = xnsynch_sleep_on(&server->mrecv, timeout, XN_RELATIVE);
- /*
- * XNRMID cannot happen, since well, the current task would be the
- * deleted object, so...
- */
- if (info & XNTIMEO) {
- err = -ETIMEDOUT; /* Timeout. */
- goto unlock_and_exit;
- } else if (info & XNBREAK) {
- err = -EINTR; /* Unblocked. */
- goto unlock_and_exit;
- }
+ do {
+ /*
+ * Wait on our receive slot for some client to enqueue
+ * itself in our send queue.
+ */
+ info = xnsynch_sleep_on(&server->mrecv, timeout, XN_RELATIVE);
+ /*
+ * XNRMID cannot happen, since well, the current task
+ * would be the deleted object, so...
+ */
+ if (info & XNTIMEO) {
+ err = -ETIMEDOUT; /* Timeout. */
+ goto unlock_and_exit;
+ }
+ if (info & XNBREAK) {
+ err = -EINTR; /* Unblocked. */
+ goto unlock_and_exit;
+ }
+ } while (!xnsynch_pended_p(&server->mrecv));
holder = getheadpq(xnsynch_wait_queue(&server->msendq));
/* There must be a valid holder since we waited for it. */
> http://www.rts.uni-hannover.de/xenomai/lxr/source/ksrc/skins/native/task.c#1976
>
> -bash-3.2# ./oops_sender
> pre-rt_task_receive()
> [ 662.423571] Unable to handle kernel paging request for data at address
> 0x0000024c
> [ 662.515607] Faulting instruction address: 0xc0070124
> [ 662.576614] Oops: Kernel access of bad area, sig: 11 [#2]
> [ 662.642806] mpc5200-simple-platform
> [ 662.685493] last sysfs file:
> [ 662.721775] Modules linked in:
> [ 662.759127] NIP: c0070124 LR: c00701c8 CTR: 00000000
> [ 662.819974] REGS: c7b8bd40 TRAP: 0300 Tainted: G D
> (2.6.36.4-00003-g1af23a4-dirty)
> [ 662.925684] MSR: 00003032 <FP,ME,IR,DR> CR: 24008482 XER: 20000000
> [ 663.003613] DAR: 0000024c, DSISR: 20000000
> [ 663.053780] TASK = c7b923f0[1227] 'oops_test_main' THREAD: c7b8a000
> [ 663.128525] GPR00: 00000000 c7b8bdf0 c7b923f0 c902a69c c042ea60 00000000
> 36291b28 c042ea60
> [ 663.231015] GPR08: c902a210 fffffe0c c902a210 c9029df8 24008422 1004a118
> 00000000 00000000
> [ 663.333503] GPR16: c040dc54 c0425ba0 fffffff0 c7b8bf50 c0425ba0 c042f058
> 00000010 c902a210
> [ 663.435993] GPR24: c03f9af8 c0425ba0 c03fb678 00000000 fffffdfc c902a200
> c7b8be20 fffffffc
> [ 663.540611] NIP [c0070124] rt_task_receive+0xc8/0x1ac
> [ 663.602534] LR [c00701c8] rt_task_receive+0x16c/0x1ac
> [ 663.664436] Call Trace:
> [ 663.694322] [c7b8bdf0] [c00701c8] rt_task_receive+0x16c/0x1ac (unreliable)
> [ 663.778687] [c7b8be10] [c0072de4] __rt_task_receive+0xd0/0x1b0
> [ 663.850245] [c7b8be90] [c0068cd0] losyscall_event+0xc8/0x328
> [ 663.919654] [c7b8bed0] [c00587c8] __ipipe_dispatch_event+0xa4/0x200
> [ 663.996532] [c7b8bf20] [c000ae78] __ipipe_syscall_root+0x58/0x164
> [ 664.071289] [c7b8bf40] [c00104b8] DoSyscall+0x20/0x5c
> [ 664.133213] --- Exception: c01 at 0xffaca7c
> [ 664.133222] LR = 0xffaca14
> [ 664.221809] Instruction dump:
> [ 664.258092] 557b07fe 90091b48 813d049c 7f9c4800 419e007c 2f890000 3929fe0c
> 419e0070
> [ 664.353104] 2f890000 3b800000 419e0008 3b89fff0 <83bc0450> 3be0ff97
> 801e000c 7f9d0040
> [ 664.452834] ---[ end trace 07ae98a3f6576a96 ]---
>
> Message from syslogd@ at Sat Feb 21 08:02:43 1970 ...
> CPUP0 kernel: [ 662.685493] last sysfs file: rt_task_send() failed: -110
> (Connection timed out)
> Killing child
>
> The oops is *not* trigger if the timeout is long enough and
> rt_task_send() returns successfully.
>
> I'm using on a PowerPC MPC5200-based system:
>
> -bash-3.2# cat /proc/ipipe/version
> 2.12-03
> -bash-3.2# cat /proc/xenomai/version
> 2.5.6
> -bash-3.2# uname -a
> Linux CPUP0 2.6.36.4-00003-g1af23a4-dirty #9 Thu Jun 9 11:56:54 CEST 2011
> ppc ppc ppc GNU/Linux
>
> Any idea what could go wrong. I have attached my litte test programs
> including Makefile. Just start it with ./oops_sender.
>
> Thanks,
>
> Wolfgang.
> _______________________________________________
> Xenomai-core mailing list
> Xenomai-core@gna.org
> https://mail.gna.org/listinfo/xenomai-core
--
Philippe.
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