Hi all,I' am trying to send small UDP datagrams in a real-time system. I can't get a satisfactory performance when I send these packets from a userspace Xenomai task using sendto() call.
That's why I tried to code a small kernel module to make some measurements. However; whenever
• A xenomai task
• An alarm function
• A thread created with kthread_run() form a xenomai task
that includes the sock_sendmsg() call runs, system crashes. However,
if a write a regular kernel module, the it works just fine...
Below you can find the code and the crash dump.Does anyone have any suggestions? Is there any other way that I can send a UDP packet from a kernel Xenomai task?
Best regards,
alphan
------- Code ---------
#include "misc_kernel.h"
#include "ncs_const.h"
#include "xenomai.h"
//TODO: Remove unnecessary includes
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kthread.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/netdevice.h>
#include <linux/ip.h>
#include <linux/in.h>
#include <linux/delay.h>
#define TASK_PRIO 99 /*
Highest RT priority */
#define TASK_MODE T_CPU(0) /* Bound to CPU #0 */
#define TASK_STKSZ 32000 /*
Stack size (in bytes) *
#define ALARM_PERIOD 1000000000
#define INADDR_SEND (unsigned long int)0xC0A80204 //192.168.2.4
in hex
#define CONNECT_PORT 6355
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Kernel UDP Transmission Latency & Jitter Test
Module");
static RT_ALARM aid;
static RT_TASK tid;
static startMarkFrame currentStartMark;
static struct socket* sock_send;
static struct sockaddr_in addr_send;
static struct msghdr msg;
static struct iovec iov;
static mm_segment_t oldfs;
static void coordTask(void *cookie) {
printk("\n");
iov.iov_base = ¤tStartMark;
iov.iov_len = sizeof(currentStartMark);
msg.msg_flags = 0;
msg.msg_name = &addr_send;
msg.msg_namelen = sizeof(struct sockaddr_in);
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_control = NULL;
oldfs = get_fs();
printk("21 ");
set_fs(KERNEL_DS);
printk("22 ");
sock_sendmsg(sock_send,&msg,sizeof(currentStartMark));
printk("23 ");
set_fs(oldfs);
printk("24 ");
currentStartMark.sequenceNumber++;
printk("25 ");
}
int coordInit(void) {
int err;
printk("\nStarting Kernel UDP Transmission Test Module...\n");
/* */
/* Create Socket */
/* */
if ((err = sock_create(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock_send))
< 0 )
{
printk("sock_create() failed with code: %d\n",err);
goto fail;
}
addr_send.sin_family = AF_INET;
addr_send.sin_addr.s_addr = htonl(INADDR_SEND);
addr_send.sin_port = htons(CONNECT_PORT);
if ((err = sock_send->ops->connect(sock_send, (struct sockaddr
*)&addr_send, sizeof(struct sockaddr), 0) < 0 ))
{
printk("connect() failed with code: %d \n",err);
goto fail;
}
/* */
/* Initialize variables */
/* */
currentStartMark.frameType = START_MARK_FRAME;
currentStartMark.sequenceNumber = 0x00;
err = rt_task_create(&tid, "Kenrel UDP Task", TASK_STKSZ, TASK_PRIO,
TASK_MODE);
if (err) {
printk("rt_task_create() failed: code %d\n", err);
goto fail;
}
rt_task_start(&tid,&coordTask,NULL);
fail:
return err;
}
void coordCleanup(void) {
//rt_alarm_delete(&aid);
rt_task_delete(&tid);
printk("\nKernel UDP module removed!\n");
}
module_init(coordInit);
module_exit(coordCleanup);
-------- Stack trace ----------
[ 454.999957] Starting Kernel UDP Transmission Test Module...
[ 455.021232] 1 2 3 4 5 6 <3>BUG: Unhandled exception over domain
Xenomai at 0xc0145cfe - switching to ROOT
[ 455.021484] Pid: 3643, comm: insmod Not tainted 2.6.26.5 #9 [ 455.021558] [<c0112351>] __ipipe_handle_exception+0x1b1/0x1c0 [ 455.021644] [<c0145cfe>] __ipipe_restore_root+0x1e/0x30 [ 455.021724] [<c03a7633>] error_code+0x6f/0x7c [ 455.021803] [<c0326c96>] __alloc_skb+0x36/0x120 [ 455.021881] [<c0145cfe>] __ipipe_restore_root+0x1e/0x30 [ 455.021960] [<c0182795>] kmem_cache_alloc+0x55/0xd0 [ 455.022001] [<c0326c96>] __alloc_skb+0x36/0x120 [ 455.022001] [<c0322c08>] sock_alloc_send_skb+0x168/0x1b0 [ 455.022001] [<c0348611>] ip_append_data+0x711/0x970 [ 455.022001] [<c0349540>] ip_generic_getfrag+0x0/0xb0 [ 455.022001] [<c0364730>] udp_sendmsg+0x2f0/0x660 [ 455.022001] [<c036ab37>] inet_sendmsg+0x37/0x70 [ 455.022001] [<c032062e>] sock_sendmsg+0xbe/0xf0 [ 455.022001] [<c0150260>] xntimer_start_aperiodic+0x0/0x200 [ 455.022001] [<c012ef50>] autoremove_wake_function+0x0/0x50 [ 455.022001] [<c0150260>] xntimer_start_aperiodic+0x0/0x200 [ 455.022001] [<c014bc35>] xnpod_suspend_thread+0x1f5/0x200 [ 455.022001] [<c027e184>] vscnprintf+0x14/0x20 [ 455.022001] [<c011cc04>] printk+0xc4/0xe0 [ 455.022001] [<f890b180>] coordTask+0x0/0x104 [deneme2] [ 455.022001] [<f890b238>] coordTask+0xb8/0x104 [deneme2] [ 455.022001] [<c014c162>] xnarch_thread_redirect+0x32/0x50 [ 455.022001] [<f890b180>] coordTask+0x0/0x104 [deneme2] [ 455.022001] ======================= [ 455.022001] ------------[ cut here ]------------ [ 455.022001] kernel BUG at kernel/ipipe/core.c:323! [ 455.022001] invalid opcode: 0000 [#1] PREEMPT[ 455.022001] Modules linked in: deneme2(+) arc4 ecb crypto_blkcipher cryptomgr crypto_algapi [last unloaded: deneme2]
[ 455.022001] [ 455.022001] Pid: 3643, comm: insmod Not tainted (2.6.26.5 #9) [ 455.022001] EIP: 0060:[<c0145cfe>] EFLAGS: 00010202 CPU: 0 [ 455.022001] EIP is at __ipipe_restore_root+0x1e/0x30 [ 455.022001] EAX: 00000000 EBX: f74586c0 ECX: c0326c96 EDX: c0491b9c [ 455.022001] ESI: 00000000 EDI: c0491b20 EBP: 000000c0 ESP: f7d37870 [ 455.022001] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068[ 455.022001] Process insmod (pid: 3643, ti=f7d36000 task=f7f2aa20 task.ti=f7512000)<0>
[ 455.022001] I-pipe domain Linux[ 455.022001] Stack: c0182795 00000000 00000000 000004d0 00000200 00000000 0000003d 000004d0 [ 455.022001] c0491b20 c0326c96 00000000 f7c3ea00 7fffffff 0000000a 000004d0 c0322c08 [ 455.022001] ffffffff 0000003d 00000000 00000000 f74fa700 00000000 00000000 f74fa700
[ 455.022001] Call Trace: [ 455.022001] [<c0182795>] kmem_cache_alloc+0x55/0xd0 [ 455.022001] [<c0326c96>] __alloc_skb+0x36/0x120 [ 455.022001] [<c0322c08>] sock_alloc_send_skb+0x168/0x1b0 [ 455.022001] [<c0348611>] ip_append_data+0x711/0x970 [ 455.022001] [<c0349540>] ip_generic_getfrag+0x0/0xb0 [ 455.022001] [<c0364730>] udp_sendmsg+0x2f0/0x660 [ 455.022001] [<c036ab37>] inet_sendmsg+0x37/0x70 [ 455.022001] [<c032062e>] sock_sendmsg+0xbe/0xf0 [ 455.022001] [<c0150260>] xntimer_start_aperiodic+0x0/0x200 [ 455.022001] [<c012ef50>] autoremove_wake_function+0x0/0x50 [ 455.022001] [<c0150260>] xntimer_start_aperiodic+0x0/0x200 [ 455.022001] [<c014bc35>] xnpod_suspend_thread+0x1f5/0x200 [ 455.022001] [<c027e184>] vscnprintf+0x14/0x20 [ 455.022001] [<c011cc04>] printk+0xc4/0xe0 [ 455.022001] [<f890b180>] coordTask+0x0/0x104 [deneme2] [ 455.022001] [<f890b238>] coordTask+0xb8/0x104 [deneme2] [ 455.022001] [<c014c162>] xnarch_thread_redirect+0x32/0x50 [ 455.022001] [<f890b180>] coordTask+0x0/0x104 [deneme2] [ 455.022001] =======================[ 455.022001] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 81 3d 20 e8 45 c0 c0 0a 55 c0 75 12 85 c0 74 09 0f ba 2d c0 d4 45 c0 00 c3 e9 a2 ff ff ff <0f> 0b eb fe 8d b4 26 00 00 00 00 8d bc 27 00 00 00 00 89 c1 8b [ 455.022001] EIP: [<c0145cfe>] __ipipe_restore_root+0x1e/0x30 SS:ESP 0068:f7d37870
[ 455.022001] ---[ end trace 415d3c300348194e ]---
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