std::thread segfault

std::thread segfault

[Matthew Lai]

I'm using my 4.4.0 SVN checked out a few days ago, and I tried to use 
C++0x's std::thread, but it kept segfaulting on me.

This is on 64-bit Linux, x86-64 (Ubuntu 8.10).

-------------------------------------------------
#include <thread>

void t() {
}

int main() {
    std::thread t1(&t);

    t1.join();
}
-------------------------------------------------

-------------------------------------------------
cyberfish@cyberfish-desktop:/tmp$ g++-4.4 -v
Using built-in specs.
Target: x86_64-linux-gnu
Configured with: ../configure --enable-languages=c,c++ --prefix=/opt/gcc 
--with-system-zlib --without-included-gettext --disable-nls 
--enable-libstdcxx-debug --enable-checking=release --build=x86_64-linux-gnu
Thread model: posix
gcc version 4.4.0 20090407 (prerelease) (GCC)
cyberfish@cyberfish-desktop:/tmp$ g++-4.4 -g -std=gnu++0x a.cpp
cyberfish@cyberfish-desktop:/tmp$ gdb a.out
GNU gdb 6.8-debian
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later 
<http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu"...
(gdb) r
Starting program: /tmp/a.out

Program received signal SIGSEGV, Segmentation fault.
0x0000000000000000 in ?? ()
(gdb) bt
#0  0x0000000000000000 in ?? ()
#1  0x00007fab24c6ffa7 in std::thread::_M_start_thread 
(this=0x7fff2d0db420,
    __b=DWARF-2 expression error: DW_OP_reg operations must be used 
either alone or in conjuction with DW_OP_piece.
)
    at 
/home/cyberfish/gcc_svn/gcc/build/x86_64-linux-gnu/libstdc++-v3/include/x86_64-linux-gnu/bits/gthr-default.h:682
#2  0x0000000000400dce in thread<void (*)()> (this=0x7fff2d0db420,
    __f=0x400bbc <t()>)
    at 
/opt/gcc/lib/gcc/x86_64-linux-gnu/4.4.0/../../../../include/c++/4.4.0/thread:134
#3  0x0000000000400bde in main () at a.cpp:7
(gdb) l
1    #include <thread>
2   
3    void t() {
4    }
5   
6    int main() {
7        std::thread t1(&t);
8   
9        t1.join();
10    }
(gdb)
-------------------------------------------------

Thanks
Matthew Lai

Re: std::thread segfault

[Timothy Brownawell]

On Tue, 2009-04-14 at 14:24 -0700, Matthew Lai wrote:
> I'm using my 4.4.0 SVN checked out a few days ago, and I tried to use 
> C++0x's std::thread, but it kept segfaulting on me.

It did this to me too, some time with google turned up (besides this
message)
   http://gcc.gnu.org/ml/libstdc++/2009-02/txt00002.txt
which makes it looks like "-pthread" is needed. And giving that option
does indeed seem to make it work here.

> This is on 64-bit Linux, x86-64 (Ubuntu 8.10).
> 
> -------------------------------------------------
> #include <thread>
> 
> void t() {
> }
> 
> int main() {
>     std::thread t1(&t);
> 
>     t1.join();
> }
> -------------------------------------------------

Re: std::thread segfault

[Matthew Lai]

Thanks!

That works for me, too.

Is it intended that -pthread is required for std::thread? Even if it 
is... I don't think "Segmentation fault" is that helpful an error message.

Matthew Lai


Timothy Brownawell wrote:
> On Tue, 2009-04-14 at 14:24 -0700, Matthew Lai wrote:
>   
>> I'm using my 4.4.0 SVN checked out a few days ago, and I tried to use 
>> C++0x's std::thread, but it kept segfaulting on me.
>>     
>
> It did this to me too, some time with google turned up (besides this
> message)
>    http://gcc.gnu.org/ml/libstdc++/2009-02/txt00002.txt
> which makes it looks like "-pthread" is needed. And giving that option
> does indeed seem to make it work here.
>
>   
>> This is on 64-bit Linux, x86-64 (Ubuntu 8.10).
>>
>> -------------------------------------------------
>> #include <thread>
>>
>> void t() {
>> }
>>
>> int main() {
>>     std::thread t1(&t);
>>
>>     t1.join();
>> }
>> -------------------------------------------------
>>     
>
>