I have struggling a week to fix a program , in the begining i got SIGBUS , but after many attempts still the program gets SIGSEGV segment fault , In bellow i post the seg fault log + source codes. would really appreciate if experts help me to fix this segment fault error. any advice is highly appreciated.
Thanks in advance
Code:LL_NODE *ll_prepend(LLIST *l, void *obj) { if (l && obj) { //line bellow is module-datastruct-llist.c:167 //mentioned in segment-fault log as frame 3 if (!ll_lock(l)) return NULL; LL_NODE *new; if(!cs_malloc(&new,sizeof(LL_NODE), -1)) return NULL; new->obj = obj; new->nxt = l->initial; l->initial = new; if (!l->last) l->last = l->initial; l->count++; ll_unlock(l); return new; } return NULL; }
Code:int32_t ll_lock(LLIST *l) { int32_t res = 1; res=cs_trylock(&l->lock); //line bellow is module-datastruct-llist.c:51 //mentioned in segment-fault log as frame 2 while (l && !l->flag && res) { cs_debug_mask(D_TRACE, "trylock ll_lock wait"); cs_sleepms(fast_rnd()%5 + 1); } return !res; }
Code:int32_t cs_trylock(pthread_mutex_t *mutex){ if(!mutex) return -1; int32_t result, oldtype; /* Make sure that we won't get interrupted while getting the lock */ pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype); //line bellow is oscam-simples.c:1233 //mentioned in segment-fault log as frame 1 if((result=pthread_mutex_trylock(mutex)) == 0){ struct s_client *cl = cs_preparelock(cur_client(), mutex); if(cl) cl->mutexstore_used++; } pthread_setcanceltype(oldtype, NULL); pthread_testcancel(); return result; }
Code:// in this function &l->lock is initialized LLIST *ll_create() { LLIST *l = cs_malloc(&l, sizeof(LLIST), 0); pthread_mutex_init(&l->lock, NULL); return l; }
if u need entire source codes:Segment fault log :
Program received signal SIGSEGV, Segmentation fault.
[Switching to LWP 1905]
0x2979b7ba in pthread_mutex_trylock () from /lib/libpthread.so.0
(gdb) bt
#0 0x2979b7ba in pthread_mutex_trylock () from /lib/libpthread.so.0
#1 0x00410d98 in cs_trylock (mutex=0x247373a4) at oscam-simples.c:1233
#2 0x0043d4aa in ll_lock (l=0x24737398) at module-datastruct-llist.c:51
#3 0x0043d956 in ll_prepend (l=0x24737398, obj=0x4a2410)
at module-datastruct-llist.c:167
#4 0x0040a66e in get_cw (client=0x4daa80, er=0x5063a0) at oscam.c:2645
#5 0x00439754 in dvbapi_process_input (demux_id=0, filter_num=0,
buffer=0x2a98bb60 "\201q=", len=320) at module-dvbapi.c:1634
#6 0x0043c866 in stapi_read_thread (sparam=0x4d1558) at module-dvbapi.c:2441
#7 0x29799486 in ?? () from /lib/libpthread.so.0
Backtrace stopped: frame did not save the PC
(gdb) info args
No symbol table info available.
module-datastruct-llist.c in trunk
oscam-simples.c in trunk
globals.h in trunk
my guess is the bug comes from pthread_mutex_trylock in oscam-simples.c : line 1233, i mean :
any advice is highly apprecited.Code:pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype); /* Line 1233 */ if((result=pthread_mutex_trylock(mutex)) == 0){