[Xenomai-help] Scheduling while atomic

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* [Xenomai-help] Scheduling while atomic
@ 2006-01-16 16:09 Jeroen Van den Keybus
  2006-01-16 17:26 ` Jan Kiszka
  2006-01-16 17:31 ` Gilles Chanteperdrix
  0 siblings, 2 replies; 5+ messages in thread
From: Jeroen Van den Keybus @ 2006-01-16 16:09 UTC (permalink / raw)
  To: xenomai

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I got a fair number of 'scheduling while atomic' entries in the dmesg log
after running a multithread Xenomai program. What do they mean ?

Jeroen.

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* Re: [Xenomai-help] Scheduling while atomic
  2006-01-16 16:09 [Xenomai-help] Scheduling while atomic Jeroen Van den Keybus
@ 2006-01-16 17:26 ` Jan Kiszka
  2006-01-16 17:31 ` Gilles Chanteperdrix
  1 sibling, 0 replies; 5+ messages in thread
From: Jan Kiszka @ 2006-01-16 17:26 UTC (permalink / raw)
  To: Jeroen Van den Keybus; +Cc: xenomai

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Jeroen Van den Keybus wrote:
> I got a fair number of 'scheduling while atomic' entries in the dmesg log
> after running a multithread Xenomai program. What do they mean ?
> 

Backtraces, i.e. the dmesg logs, please.

The general meaning is that the Linux scheduler was invoked in a
non-schedulable context, e.g. with preemption lock held. The precise
meaning can only be derived from that output.

Jan


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^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [Xenomai-help] Scheduling while atomic
  2006-01-16 16:09 [Xenomai-help] Scheduling while atomic Jeroen Van den Keybus
  2006-01-16 17:26 ` Jan Kiszka
@ 2006-01-16 17:31 ` Gilles Chanteperdrix
       [not found]   ` <fd6a47a90601170609u594d4fd4k@domain.hid>
  1 sibling, 1 reply; 5+ messages in thread
From: Gilles Chanteperdrix @ 2006-01-16 17:31 UTC (permalink / raw)
  To: Jeroen Van den Keybus; +Cc: xenomai

Jeroen Van den Keybus wrote:
 > I got a fair number of 'scheduling while atomic' entries in the dmesg log
 > after running a multithread Xenomai program. What do they mean ?

You may have found a bug. Could you provide an program (preferably as
short as possible) which causes these messages ?

-- 


					    Gilles Chanteperdrix.


^ permalink raw reply	[flat|nested] 5+ messages in thread

[parent not found: <fd6a47a90601170609u594d4fd4k@domain.hid>]

* [Xenomai-help] Scheduling while atomic
       [not found]   ` <fd6a47a90601170609u594d4fd4k@domain.hid>
@ 2006-01-17 14:11     ` Jeroen Van den Keybus
  2006-01-17 15:45     ` [Xenomai-core] " Gilles Chanteperdrix
  1 sibling, 0 replies; 5+ messages in thread
From: Jeroen Van den Keybus @ 2006-01-17 14:11 UTC (permalink / raw)
  To: xenomai

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Gilles, Jan,


The offending program is quite complex (several .c files and
a considerable .h file tree) and involves 2 computers. However, I think I
can narrow down the problem to concurrent access (from 2 Xenomai threads in
2nd domain) to the same Linux file descriptor for a TCP/IP connection.

In order to rule this out, I have put RT_MUTEXes around the send() and
recv() calls.However, I still received 'scheduling while atomic'. Further
investigation, however, has shown that the mutexes seem to fail:
rt_mutex_enquire() returns 0 or even -1 after acquisition of the lock. With
this program, I didn't (yet) receive the 'scheduling...' error, but by
increasing the task repetition rate, it should be a matter of (a long) time
(both tasks arriving at a blocking write).

I have compiled a program that represents the structure of the original
program. Could you have a look and see if I'm not making a mistake here ?

For proper following up, I've also attached the dmesg log asked for earlier
by Jan.


/* TEST_MUTEX.C */

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <math.h>

#include <native/task.h>
#include <native/mutex.h>
#include <native/sem.h>

int fd, err;
RT_MUTEX m;
RT_SEM s;

#define CHECK(arg) check(arg, __LINE__)

int check(int r, int n)
{
    if (r != 0)
        fprintf(stderr, "L%d: %s.\n", n, strerror(-r));
    return(r);
}

void output(char c) {
    static int cnt = 0;
    int n;
    char buf[2];
    RT_MUTEX_INFO mutexinfo;

    buf[0] = c;

    if (cnt == 80) {
        buf[1] = '\n';
        n = 2;
        cnt = 0;
    }
    else {
        n = 1;
        cnt++;
    }

    CHECK(rt_mutex_inquire(&m, &mutexinfo));
    if (mutexinfo.lockcnt <= 0) {
        RT_TASK_INFO taskinfo;
        CHECK(rt_task_inquire(NULL, &taskinfo));
        fprintf(stderr, "ALERT: No lock! (lockcnt=%d) Offending task: %s\n",
                mutexinfo.lockcnt, taskinfo.name );
    }

    if (write(fd, buf, n) != n) {
        fprintf(stderr, "File write error.\n");
        CHECK(rt_sem_v(&s));
    }
}

void task0(void *arg)
{
    while (1) {
        CHECK(rt_task_sleep((float)rand()*1.0e7/(float)RAND_MAX));
        CHECK(rt_mutex_lock(&m, TM_INFINITE));
        output('0');
        CHECK(rt_mutex_unlock(&m));
    }
}

void task1(void *arg)
{
    while (1) {
        CHECK(rt_task_sleep((float)rand()*1.0e7/(float)RAND_MAX));
        CHECK(rt_mutex_lock(&m, TM_INFINITE));
        output('1');
        CHECK(rt_mutex_unlock(&m));
    }
}

void sighandler(int arg)
{
    CHECK(rt_sem_v(&s));
}

int main(int argc, char *argv[])
{
    RT_TASK t, t0, t1;

    if ((fd = open("dump.txt", O_CREAT | O_RDWR)) < 0)
        fprintf(stderr, "File open error.\n");
    else {
        CHECK(rt_timer_start(TM_ONESHOT));

        CHECK(rt_mutex_create(&m, "mutex"));
        CHECK(rt_sem_create(&s, "sem", 0, S_PRIO));

        signal(SIGINT, sighandler);

        CHECK(rt_task_create(&t0, "task0", 0, 30, T_FPU));
        CHECK(rt_task_start(&t0, task0, NULL));
        CHECK(rt_task_create(&t1, "task1", 0, 29, T_FPU));
        CHECK(rt_task_start(&t1, task1, NULL));
        CHECK(rt_task_shadow(&t, "main", 1, T_FPU));

        CHECK(rt_sem_p(&s, TM_INFINITE));
        signal(SIGINT, SIG_IGN);

        CHECK(rt_task_delete(&t1));
        CHECK(rt_task_delete(&t0));

        CHECK(rt_sem_delete(&s));
        CHECK(rt_mutex_delete(&m));

        rt_timer_stop();

        close(fd);
    }
    return 0;
}

Compiled with GCC 4.0.2:

gcc mtest.c -o mtest $(xeno-config --xeno-cflags) $(xeno-config
---xeno-ldflags)



Run on kernel 2.6.15, Adeos 1.1-03, Xenomai SVN rev. 462



dmesg output (usually not that long - the truncated first line is actually
there - it is not the top of the dmesg log):

pe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
scheduling while atomic: ext_upload/0x00000002/12490
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0148ade>] ipipe_trace_end+0x35/0x37
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
note: ext_upload[12490] exited with preempt_count 2
scheduling while atomic: ext_upload/0x00000002/12661
 [<c03b4c64>] schedule+0x4b4/0x790
 [<c011a0ca>] __wake_up_sync+0x67/0xb8
 [<c0155455>] xnshadow_harden+0xc6/0xdd
 [<c0156c5b>] losyscall_event+0x8c/0x1c0
 [<c0147473>] __ipipe_dispatch_event+0x90/0x173
 [<c011697a>] __ipipe_syscall_root+0x36/0x110
 [<c0103434>] system_call+0x20/0x41
note: ext_upload[12661] exited with preempt_count 2

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^ permalink raw reply	[flat|nested] 5+ messages in thread

* [Xenomai-core] Re: [Xenomai-help] Scheduling while atomic
       [not found]   ` <fd6a47a90601170609u594d4fd4k@domain.hid>
  2006-01-17 14:11     ` Jeroen Van den Keybus
@ 2006-01-17 15:45     ` Gilles Chanteperdrix
  1 sibling, 0 replies; 5+ messages in thread
From: Gilles Chanteperdrix @ 2006-01-17 15:45 UTC (permalink / raw)
  To: xenomai

[-- Attachment #1: message body and .signature --]
[-- Type: text/plain, Size: 1694 bytes --]

Jeroen Van den Keybus wrote:
 > Gilles, Jan,
 > 
 > 
 > The offending program is quite complex (several .c files and
 > a considerable .h file tree) and involves 2 computers. However, I think I
 > can narrow down the problem to concurrent access (from 2 Xenomai threads in
 > 2nd domain) to the same Linux file descriptor for a TCP/IP connection.
 > 
 > In order to rule this out, I have put RT_MUTEXes around the send() and
 > recv() calls.However, I still received 'scheduling while atomic'. Further
 > investigation, however, has shown that the mutexes seem to fail:
 > rt_mutex_enquire() returns 0 or even -1 after acquisition of the lock. With
 > this program, I didn't (yet) receive the 'scheduling...' error, but by
 > increasing the task repetition rate, it should be a matter of (a long) time
 > (both tasks arriving at a blocking write).
 > 
 > I have compiled a program that represents the structure of the original
 > program. Could you have a look and see if I'm not making a mistake here ?
 > 
 > For proper following up, I've also attached the dmesg log asked for earlier
 > by Jan.

Looking at the message log, it seems xnshadow_harden is called at a
point where irqs are disabled. But is there no other error before these
"scheduling while atomic" messages ? If not, could you try and enable
the nucleus debugging ?

In case there is no error before the error messages, even with nucleus
debugging activated, I attached a patch which breaks nklock and
activates interrupts on xnshadow_harden entry and restore the caller
state on xnshadow_harden exit. Could you test it and report if you still
see the "scheduling while atomic" messages ?

-- 


					    Gilles Chanteperdrix.

[-- Attachment #2: xeno-harden.diff --]
[-- Type: text/plain, Size: 1128 bytes --]

Index: ksrc/nucleus/shadow.c
===================================================================
--- ksrc/nucleus/shadow.c	(revision 464)
+++ ksrc/nucleus/shadow.c	(working copy)
@@ -439,13 +439,17 @@
        preemption. */
     struct __gatekeeper *gk = &gatekeeper[task_cpu(this_task)];
     xnthread_t *thread = xnshadow_thread(this_task);
+    spl_t s;
 
     if (!thread)
 	return -EPERM;
 
+    xnlock_get_irqsave(&nklock, s);
+    xnlock_clear_irqon(&nklock);
+
     if (signal_pending(this_task) ||
 	down_interruptible(&gk->sync)) /* Grab the request token. */
-	return -ERESTARTSYS;
+        goto out_interrupted;
 
     xnltt_log_event(xeno_ev_primarysw,this_task->comm);
 
@@ -495,6 +499,8 @@
 			    thread->name,
 			    xnthread_user_pid(thread));
 #endif /* CONFIG_XENO_OPT_DEBUG */
+out_interrupted:
+            xnlock_put_irqrestore(&nklock, s);
 	    return -ERESTARTSYS;
 	}
     }
@@ -510,7 +516,7 @@
     if (xnthread_signaled_p(thread))
         xnpod_dispatch_signals();
 
-    xnlock_clear_irqon(&nklock);
+    xnlock_put_irqrestore(&nklock, s);
 
     xnltt_log_event(xeno_ev_primary,thread->name);
 

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2006-01-17 15:45 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2006-01-16 16:09 [Xenomai-help] Scheduling while atomic Jeroen Van den Keybus
2006-01-16 17:26 ` Jan Kiszka
2006-01-16 17:31 ` Gilles Chanteperdrix
     [not found]   ` <fd6a47a90601170609u594d4fd4k@domain.hid>
2006-01-17 14:11     ` Jeroen Van den Keybus
2006-01-17 15:45     ` [Xenomai-core] " Gilles Chanteperdrix

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