Hi,

I am currently working with threads using linux 2.6.11 and glibc 2.3.5 on x86. When i am trying to create thread with user defined stacks glibc gives segmentation fault. I have written a wrapper to pthread_create () and generated shared object for the same. When i am trying to create any thread (for user defined stack) using this shared object i am getting segmentation fault. If i don't create shared object and try to create thread (with user defined stack) using same code, it works fine. I am not able to understand this behavior. Why creating a thread using shared object shall result in segfault. And how to overcome this situation.

NOTE: I got same behavior when tried with linux 2.6.12 and glibc-2.3.6 on arm platform.


gdb output for the behavior is :

Loaded symbols for /lib/libgcc_s.so.1
#0 0x0018a777 in memset () from /lib/libc.so.6
(gdb) bt'
#0 0x0018a777 in memset () from /lib/libc.so.6
No symbol table info available.
#1 0x003e27ef in pthread_create@@GLIBC_2.1 () from /lib/libpthread.so.0
No symbol table info available.
#2 0x003e29fd in pthread_create@GLIBC_2.0 () from /lib/libpthread.so.0
No symbol table info available.
#3 0x00ed9880 in process_create (entry_point=0x8048f4c <ThreadEntryPoint>, pArg=0x1, pStack=0x82e08a8, ulStack_Size=16384, ulPrio=127)
at multithreading.c:1916
stThAttr = {__size = "c\000\000\000\002\000\000\000j\000\000\000\000\02 0\000\000¨H.\b\000@", '\0' <repeats 13 times>, __align = 99}
stSchedParam = {__sched_priority = 99}
pstTd = (ThreadData_t *) 0xedd7d8
state = 0
chPriority = 99 'c'
ulRetVal = 0
pRetVal = 0x0
__FUNCTION__ = "process_create"
#4 0x08049af8 in process_create_test (ulInParam=1) at multithreading_test.c:539
ulIndex = 0
lRetVal = -1
ulThreadIndex = 1
lTestPassFlag = 0
stack = (void *) 0x82d88a8
pStack = (void *) 0x82e08a8
ulPrio = 127
stackSize = 16384
__FUNCTION__ = "process_create_test"
#5 0x0804b14b in main () at multithreading_test.c:1460
chChoice = "1"
lChoice = 1
stack = (void *) 0x0
stackSize = 0
ulPrio = 0
ulLoopIndex = 0
stTime = 134533384
stTimeInfo = {tm_sec = 4, tm_min = 53, tm_hour = 7, tm_mday = 7, tm_mon = 3, tm_year = 74, tm_wday = 0, tm_yday = 96, tm_isdst = 0,
tm_gmtoff = 19800, tm_zone = 0x82d81b8 "IST"}
achTimebuf = "04/07/1974 07:53:w"
stThAttr = {__size = '\0' <repeats 13 times>, "\020", '\0' <repeats 21 times>, __align = 0}
lFlag = 1
chFlag = 0
lTestPassFlag = 0
ulThreadIndex = 0
ulloopIndex = 1
ulThreadId = {0, 0, 0, 0}
__FUNCTION__ = "main"
(gdb) f 0
#0 0x0018a777 in memset () from /lib/libc.so.6
(gdb) f 1
#1 0x003e27ef in pthread_create@@GLIBC_2.1 () from /lib/libpthread.so.0
(gdb)


Please let me know if someone can help me.

Thanks,
Ashish