Jeff Weber wrote:
> I get a segfault when attempting to rt_mutex_acquire a mutex created in
> kernel space. I've reduced the issue to the following sample code.
> Help finding my mistake is appreciated.
>
> TIA,
> Jeff
>
>
> Kernel space Code:
> #include <linux/module.h>
> #include <linux/init.h>
> #include <native/mutex.h>
> #include "testAPI.h" /* defines MTXNAME */
>
> #define MODNAME "XenoTest"
>
> static RT_MUTEX sMtx;
>
> static int __init mymodule_init(void)
> {
> int status;
>
> status = rt_mutex_create(&sMtx, MTXNAME);
> if (status) {
> printk ("rt_mutex_create: %d\n", status);
> return 1;
> }
>
> printk ("loaded module %s\n", MODNAME);
> return 0;
> }
>
> static void __exit mymodule_exit(void)
> {
> rt_mutex_delete(&sMtx);
>
> printk ("unloaded module %s\n", MODNAME);
> return;
> }
>
> module_init(mymodule_init);
> module_exit(mymodule_exit);
>
> MODULE_LICENSE("GPL");
>
>
>
> User space Code:
> #include <stdio.h>
> #include <sys/mman.h>
> #include <native/mutex.h>
> #include <native/task.h>
>
> #include "testAPI.h" /* defines MTXNAME */
>
> #define PRIO 0
> #define MODE 0
>
> int main(void)
> {
> RT_MUTEX mtx;
> RT_TASK tsk;
> RT_MUTEX_INFO info;
> int status;
>
> mlockall(MCL_CURRENT|MCL_FUTURE);
>
> status = rt_task_shadow(&tsk, NULL, PRIO, MODE);
> if (status) {
> fprintf(stderr, "rt_task_shadow: %d\n", status);
> return 1;
> }
>
> status = rt_mutex_bind(&mtx, MTXNAME, TM_INFINITE);
> if (status) {
> fprintf(stderr, "rt_mutex_bind: %d\n", status);
> return 1;
> }
>
> status = rt_mutex_inquire(&mtx, &info);
> if (status) {
> fprintf(stderr, "rt_mutex_inquire: %d\n", status);
> return 1;
> }
>
> status = rt_mutex_acquire(&mtx, TM_INFINITE); /* SEGFAULT HERE! */
> if (status) {
> fprintf(stderr, "rt_mutex_acquire: %d\n", status);
> return 1;
> }
>
> status = rt_mutex_release(&mtx);
> if (status) {
> fprintf(stderr, "rt_mutex_release: %d\n", status);
> return 1;
> }
>
> printf("test success\n"); // back to primary mode
> return 0;
> }
>
> my kernel
>
> backtrace:
> Program terminated with signal 11, Segmentation fault.
> #0 0xb770077a in xnarch_atomic_cmpxchg (v=0xb777ac00, old=0, newval=21)
> at ../../../src/include/asm/xenomai/atomic.h:95
> 95 __asm__ __volatile__(LOCK_PREFIX "cmpxchgl %1,%2"
> (gdb) bt full
> #0 0xb770077a in xnarch_atomic_cmpxchg (v=0xb777ac00, old=0, newval=21)
> at ../../../src/include/asm/xenomai/atomic.h:95
> ptr = 0xb777ac00
> prev = 4294967295
> #1 0xb7700815 in xnsynch_fast_acquire (fastlock=0xb777ac00, new_ownerh=21)
> at ../../../include/nucleus/synch.h:52
> lock_state = 3077595124
> #2 0xb7700c3a in rt_mutex_acquire_inner (mutex=0xbfecd690, timeout=0,
> mode=XN_RELATIVE) at mutex.c:83
> err = 134513420
> cur = 21
> #3 0xb7700e01 in rt_mutex_acquire (mutex=0xbfecd690, timeout=0) at
> mutex.c:129
> No locals.
> #4 0x0804884a in main () at uspace.c:38
> mtx = {opaque = 19, fastlock = 0xb777ac00, lockcnt = 0}
> tsk = {opaque = 21, opaque2 = 3075921616}
> info = {locked = 0, nwaiters = 0,
> name = "TestMtx\000\000\000\060\000@\236i\340\000\177%", '\000'
> <repeats 12 times>,
> owner =
> "\000\000\000\000\364\036\331\336\020\037\331\336\365Pd\340\005\005UU\000\037\331\336\000\000\000\000\023\000\000"}
> status = 0
>
> my config:
> arch: x86
> linux: 2.6.35.10
> xenomai: 2.5.5.2
32 bits? 64 bits? uniprocessor? multiprocessor?
--
Gilles.
_______________________________________________
Xenomai-help mailing list
[email protected]
https://mail.gna.org/listinfo/xenomai-help
