Public bug reported:
pthread_setattr_default_np race condition with pthread_create.
When creating a new thread with pthread_create and a NULL
pthread_attr_t* argument, the pthread_attr_t* argument must come from
the last call to pthread_setattr_default_np preceding the call to
pthread_create.
It seems that there is a race condition in glibc implementation such
that pthread_attr_t* argument comes from a pthread_setattr_default_np
call that succeeds a pthread_create call.
Example:
[max@supernova:~/src/test] $ g++ --version
g++ (Ubuntu 8.3.0-6ubuntu1~18.04.1) 8.3.0
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
[max@supernova:~/src/test] $ cat test.cc
#include <cstdio>
#include <thread>
#include <system_error>
#include <pthread.h>
void set_default_thread_stack_size(size_t size) {
pthread_attr_t attr;
if(int err = ::pthread_attr_init(&attr))
throw std::system_error(err, std::system_category(),
"pthread_attr_init");
if(int err = ::pthread_attr_setstacksize(&attr, size))
throw std::system_error(err, std::system_category(),
"pthread_attr_setstacksize");
if(int err = ::pthread_setattr_default_np(&attr))
throw std::system_error(err, std::system_category(),
"pthread_setattr_default_np");
if(int err = ::pthread_attr_destroy(&attr))
throw std::system_error(err, std::system_category(),
"pthread_attr_destroy");
}
void another_thread() {
pthread_attr_t attr;
if(int err = ::pthread_attr_init(&attr))
throw std::system_error(err, std::system_category(),
"pthread_attr_init");
size_t stack_size;
if(int err = ::pthread_attr_getstacksize(&attr, &stack_size))
throw std::system_error(err, std::system_category(),
"pthread_attr_getstacksize");
if(int err = ::pthread_attr_destroy(&attr))
throw std::system_error(err, std::system_category(),
"pthread_attr_destroy");
std::printf("thread stack size is %zu\n", stack_size);
}
int main() {
another_thread();
std::thread t0(another_thread);
set_default_thread_stack_size(1024 * 1024);
std::thread t1(another_thread);
t0.join();
t1.join();
}
[max@supernova:~/src/test] $ g++ -std=gnu++14 -W{all,extra,error} -O3
-march=native -o test test.cc -pthread
[max@supernova:~/src/test] $ ldd test
linux-vdso.so.1 (0x00007ffd74d74000)
libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f597ed00000)
libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f597eae8000)
libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f597e8c9000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f597e4d8000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f597e13a000)
/lib64/ld-linux-x86-64.so.2 (0x00007f597f28d000)
[max@supernova:~/src/test] $ /lib/x86_64-linux-gnu/libc.so.6
GNU C Library (Ubuntu GLIBC 2.27-3ubuntu1) stable release version 2.27.
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 7.3.0.
libc ABIs: UNIQUE IFUNC
For bug reporting instructions, please see:
<https://bugs.launchpad.net/ubuntu/+source/glibc/+bugs>.
[max@supernova:~/src/test] $ ./test
thread stack size is 8720384
thread stack size is 1048576
thread stack size is 1048576
The above output is incorrect. The expected output is:
thread stack size is 8720384
thread stack size is 8720384
thread stack size is 1048576
If `t0.join();` line is moved to right after `std::thread
t0(another_thread);` line then the code produces the correct output.
It appears that setting the default pthread_attr_t is not atomic/ordered
with respect to pthread_create calls.
** Affects: glibc (Ubuntu)
Importance: Undecided
Status: New
** Tags: glibc libc nptl pthreads threads
** Description changed:
pthread_setattr_default_np race condition with pthread_create.
When creating a new thread with pthread_create and a NULL
pthread_attr_t* argument, the pthread_attr_t* argument must come from
the last call to pthread_setattr_default_np preceding the call to
pthread_create.
It seems that there is a race condition in glibc implementation such
that pthread_attr_t* argument comes from a pthread_setattr_default_np
call that succeeds a pthread_create call.
Example:
-
- [max@supernova:~/src/test] $ /lib/x86_64-linux-gnu/libc.so.6
- GNU C Library (Ubuntu GLIBC 2.27-3ubuntu1) stable release version 2.27.
- Copyright (C) 2018 Free Software Foundation, Inc.
- This is free software; see the source for copying conditions.
- There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
- PARTICULAR PURPOSE.
- Compiled by GNU CC version 7.3.0.
- libc ABIs: UNIQUE IFUNC
- For bug reporting instructions, please see:
- <https://bugs.launchpad.net/ubuntu/+source/glibc/+bugs>.
[max@supernova:~/src/test] $ g++ --version
g++ (Ubuntu 8.3.0-6ubuntu1~18.04.1) 8.3.0
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
[max@supernova:~/src/test] $ cat test.cc
#include <cstdio>
#include <thread>
#include <system_error>
#include <pthread.h>
void set_default_thread_stack_size(size_t size) {
- pthread_attr_t attr;
- if(int err = ::pthread_attr_init(&attr))
- throw std::system_error(err, std::system_category(),
"pthread_attr_init");
- if(int err = ::pthread_attr_setstacksize(&attr, size))
- throw std::system_error(err, std::system_category(),
"pthread_attr_setstacksize");
- if(int err = ::pthread_setattr_default_np(&attr))
- throw std::system_error(err, std::system_category(),
"pthread_setattr_default_np");
- if(int err = ::pthread_attr_destroy(&attr))
- throw std::system_error(err, std::system_category(),
"pthread_attr_destroy");
+ pthread_attr_t attr;
+ if(int err = ::pthread_attr_init(&attr))
+ throw std::system_error(err, std::system_category(),
"pthread_attr_init");
+ if(int err = ::pthread_attr_setstacksize(&attr, size))
+ throw std::system_error(err, std::system_category(),
"pthread_attr_setstacksize");
+ if(int err = ::pthread_setattr_default_np(&attr))
+ throw std::system_error(err, std::system_category(),
"pthread_setattr_default_np");
+ if(int err = ::pthread_attr_destroy(&attr))
+ throw std::system_error(err, std::system_category(),
"pthread_attr_destroy");
}
void another_thread() {
- pthread_attr_t attr;
- if(int err = ::pthread_attr_init(&attr))
- throw std::system_error(err, std::system_category(),
"pthread_attr_init");
- size_t stack_size;
- if(int err = ::pthread_attr_getstacksize(&attr, &stack_size))
- throw std::system_error(err, std::system_category(),
"pthread_attr_getstacksize");
- if(int err = ::pthread_attr_destroy(&attr))
- throw std::system_error(err, std::system_category(),
"pthread_attr_destroy");
- std::printf("thread stack size is %zu\n", stack_size);
+ pthread_attr_t attr;
+ if(int err = ::pthread_attr_init(&attr))
+ throw std::system_error(err, std::system_category(),
"pthread_attr_init");
+ size_t stack_size;
+ if(int err = ::pthread_attr_getstacksize(&attr, &stack_size))
+ throw std::system_error(err, std::system_category(),
"pthread_attr_getstacksize");
+ if(int err = ::pthread_attr_destroy(&attr))
+ throw std::system_error(err, std::system_category(),
"pthread_attr_destroy");
+ std::printf("thread stack size is %zu\n", stack_size);
}
int main() {
- another_thread();
- std::thread t0(another_thread);
- set_default_thread_stack_size(1024 * 1024);
- std::thread t1(another_thread);
- t0.join();
- t1.join();
+ another_thread();
+ std::thread t0(another_thread);
+ set_default_thread_stack_size(1024 * 1024);
+ std::thread t1(another_thread);
+ t0.join();
+ t1.join();
}
[max@supernova:~/src/test] $ g++ -std=gnu++14 -W{all,extra,error} -O3
-march=native -o test test.cc -pthread
- [max@supernova:~/src/test] $ ./test
+ [max@supernova:~/src/test] $ ldd test
+ linux-vdso.so.1 (0x00007ffd74d74000)
+ libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6
(0x00007f597ed00000)
+ libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1
(0x00007f597eae8000)
+ libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0
(0x00007f597e8c9000)
+ libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f597e4d8000)
+ libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f597e13a000)
+ /lib64/ld-linux-x86-64.so.2 (0x00007f597f28d000)
+
+ [max@supernova:~/src/test] $ /lib/x86_64-linux-gnu/libc.so.6
+ GNU C Library (Ubuntu GLIBC 2.27-3ubuntu1) stable release version 2.27.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This is free software; see the source for copying conditions.
+ There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
+ PARTICULAR PURPOSE.
+ Compiled by GNU CC version 7.3.0.
+ libc ABIs: UNIQUE IFUNC
+ For bug reporting instructions, please see:
+ <https://bugs.launchpad.net/ubuntu/+source/glibc/+bugs>.
+
+ [max@supernova:~/src/test] $ ./test
thread stack size is 8720384
thread stack size is 1048576
thread stack size is 1048576
The above output is incorrect. The expected output is:
thread stack size is 8720384
thread stack size is 8720384
thread stack size is 1048576
If `t0.join();` line is moved to right after `std::thread
t0(another_thread);` line then the code produces the correct output.
It looks that setting the default pthread_attr_t is not atomic with
respect to pthread_create calls.
** Description changed:
pthread_setattr_default_np race condition with pthread_create.
When creating a new thread with pthread_create and a NULL
pthread_attr_t* argument, the pthread_attr_t* argument must come from
the last call to pthread_setattr_default_np preceding the call to
pthread_create.
It seems that there is a race condition in glibc implementation such
that pthread_attr_t* argument comes from a pthread_setattr_default_np
call that succeeds a pthread_create call.
Example:
[max@supernova:~/src/test] $ g++ --version
g++ (Ubuntu 8.3.0-6ubuntu1~18.04.1) 8.3.0
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
[max@supernova:~/src/test] $ cat test.cc
#include <cstdio>
#include <thread>
#include <system_error>
#include <pthread.h>
void set_default_thread_stack_size(size_t size) {
pthread_attr_t attr;
if(int err = ::pthread_attr_init(&attr))
throw std::system_error(err, std::system_category(),
"pthread_attr_init");
if(int err = ::pthread_attr_setstacksize(&attr, size))
throw std::system_error(err, std::system_category(),
"pthread_attr_setstacksize");
if(int err = ::pthread_setattr_default_np(&attr))
throw std::system_error(err, std::system_category(),
"pthread_setattr_default_np");
if(int err = ::pthread_attr_destroy(&attr))
throw std::system_error(err, std::system_category(),
"pthread_attr_destroy");
}
void another_thread() {
pthread_attr_t attr;
if(int err = ::pthread_attr_init(&attr))
throw std::system_error(err, std::system_category(),
"pthread_attr_init");
size_t stack_size;
if(int err = ::pthread_attr_getstacksize(&attr, &stack_size))
throw std::system_error(err, std::system_category(),
"pthread_attr_getstacksize");
if(int err = ::pthread_attr_destroy(&attr))
throw std::system_error(err, std::system_category(),
"pthread_attr_destroy");
std::printf("thread stack size is %zu\n", stack_size);
}
int main() {
another_thread();
std::thread t0(another_thread);
set_default_thread_stack_size(1024 * 1024);
std::thread t1(another_thread);
t0.join();
t1.join();
}
[max@supernova:~/src/test] $ g++ -std=gnu++14 -W{all,extra,error} -O3
-march=native -o test test.cc -pthread
[max@supernova:~/src/test] $ ldd test
- linux-vdso.so.1 (0x00007ffd74d74000)
- libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6
(0x00007f597ed00000)
- libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1
(0x00007f597eae8000)
- libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0
(0x00007f597e8c9000)
- libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f597e4d8000)
- libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f597e13a000)
- /lib64/ld-linux-x86-64.so.2 (0x00007f597f28d000)
+ linux-vdso.so.1 (0x00007ffd74d74000)
+ libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6
(0x00007f597ed00000)
+ libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f597eae8000)
+ libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f597e8c9000)
+ libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f597e4d8000)
+ libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f597e13a000)
+ /lib64/ld-linux-x86-64.so.2 (0x00007f597f28d000)
[max@supernova:~/src/test] $ /lib/x86_64-linux-gnu/libc.so.6
GNU C Library (Ubuntu GLIBC 2.27-3ubuntu1) stable release version 2.27.
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 7.3.0.
libc ABIs: UNIQUE IFUNC
For bug reporting instructions, please see:
<https://bugs.launchpad.net/ubuntu/+source/glibc/+bugs>.
[max@supernova:~/src/test] $ ./test
thread stack size is 8720384
thread stack size is 1048576
thread stack size is 1048576
The above output is incorrect. The expected output is:
thread stack size is 8720384
thread stack size is 8720384
thread stack size is 1048576
If `t0.join();` line is moved to right after `std::thread
t0(another_thread);` line then the code produces the correct output.
- It looks that setting the default pthread_attr_t is not atomic with
+ It appears that setting the default pthread_attr_t is not atomic with
respect to pthread_create calls.
** Description changed:
pthread_setattr_default_np race condition with pthread_create.
When creating a new thread with pthread_create and a NULL
pthread_attr_t* argument, the pthread_attr_t* argument must come from
the last call to pthread_setattr_default_np preceding the call to
pthread_create.
It seems that there is a race condition in glibc implementation such
that pthread_attr_t* argument comes from a pthread_setattr_default_np
call that succeeds a pthread_create call.
Example:
[max@supernova:~/src/test] $ g++ --version
g++ (Ubuntu 8.3.0-6ubuntu1~18.04.1) 8.3.0
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
[max@supernova:~/src/test] $ cat test.cc
#include <cstdio>
#include <thread>
#include <system_error>
#include <pthread.h>
void set_default_thread_stack_size(size_t size) {
pthread_attr_t attr;
if(int err = ::pthread_attr_init(&attr))
throw std::system_error(err, std::system_category(),
"pthread_attr_init");
if(int err = ::pthread_attr_setstacksize(&attr, size))
throw std::system_error(err, std::system_category(),
"pthread_attr_setstacksize");
if(int err = ::pthread_setattr_default_np(&attr))
throw std::system_error(err, std::system_category(),
"pthread_setattr_default_np");
if(int err = ::pthread_attr_destroy(&attr))
throw std::system_error(err, std::system_category(),
"pthread_attr_destroy");
}
void another_thread() {
pthread_attr_t attr;
if(int err = ::pthread_attr_init(&attr))
throw std::system_error(err, std::system_category(),
"pthread_attr_init");
size_t stack_size;
if(int err = ::pthread_attr_getstacksize(&attr, &stack_size))
throw std::system_error(err, std::system_category(),
"pthread_attr_getstacksize");
if(int err = ::pthread_attr_destroy(&attr))
throw std::system_error(err, std::system_category(),
"pthread_attr_destroy");
std::printf("thread stack size is %zu\n", stack_size);
}
int main() {
another_thread();
std::thread t0(another_thread);
set_default_thread_stack_size(1024 * 1024);
std::thread t1(another_thread);
t0.join();
t1.join();
}
[max@supernova:~/src/test] $ g++ -std=gnu++14 -W{all,extra,error} -O3
-march=native -o test test.cc -pthread
[max@supernova:~/src/test] $ ldd test
linux-vdso.so.1 (0x00007ffd74d74000)
libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6
(0x00007f597ed00000)
libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f597eae8000)
libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f597e8c9000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f597e4d8000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f597e13a000)
/lib64/ld-linux-x86-64.so.2 (0x00007f597f28d000)
[max@supernova:~/src/test] $ /lib/x86_64-linux-gnu/libc.so.6
GNU C Library (Ubuntu GLIBC 2.27-3ubuntu1) stable release version 2.27.
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 7.3.0.
libc ABIs: UNIQUE IFUNC
For bug reporting instructions, please see:
<https://bugs.launchpad.net/ubuntu/+source/glibc/+bugs>.
[max@supernova:~/src/test] $ ./test
thread stack size is 8720384
thread stack size is 1048576
thread stack size is 1048576
The above output is incorrect. The expected output is:
thread stack size is 8720384
thread stack size is 8720384
thread stack size is 1048576
If `t0.join();` line is moved to right after `std::thread
t0(another_thread);` line then the code produces the correct output.
- It appears that setting the default pthread_attr_t is not atomic with
- respect to pthread_create calls.
+ It appears that setting the default pthread_attr_t is not atomic/ordered
+ with respect to pthread_create calls.
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1844022
Title:
pthread_setattr_default_np race condition with pthread_create.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/1844022/+subscriptions
--
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
