Logging in a static function causes segfault

[godbyk]

Previously, logging from a static function used to work fine. It would just log to the console because InitGoogleLogging() hadn't been called yet.

Now, logging from a static function causes the program to segfault.

Here's a short test program that demonstrates the problem. The static bool b = f("..."); line triggers the crash. If that line is commented out, the program runs fine.

#include <glog/logging.h>
#include <string>

bool f(const std::string& message)
{
    LOG(INFO) << message;
    return true;
}

// Uncommenting the following line will trigger the crash
//static bool b = f("Logging before main() crashes.");

int main(int argc, char* argv[])
{
    f("Logging after main() but before InitGoogleLogging() is fine.");
    google::InitGoogleLogging(argv[0]);
    f("Logging after InitGoogleLogging() is obviously fine.");

    return 0;
}

Example stack trace from gdb:

#0  0x00007ffff796eae0 in std::string::empty() const () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#1  0x0000000000408366 in google::LogMessage::Init (this=0x7fffffffd458, file=0x42d484 "static_log.cpp", line=6, severity=0, 
    send_method=(void (google::LogMessage::*)(google::LogMessage * const)) 0x4087f0 <google::LogMessage::SendToLog()>)
    at /home/godbyk/git/glog/src/logging.cc:1251
#2  0x0000000000407b79 in google::LogMessage::LogMessage (this=0x7fffffffd458, file=0x42d484 "static_log.cpp", line=6)
    at /home/godbyk/git/glog/src/logging.cc:1160
#3  0x0000000000405925 in f (message="Logging before main() crashes.") at static_log.cpp:6
#4  0x000000000040516f in __cxx_global_var_init () at static_log.cpp:11
#5  0x00000000004051fe in _GLOBAL__sub_I_static_log.cpp ()
#6  0x000000000042d3ed in __libc_csu_init ()
#7  0x00007ffff6fe49cf in __libc_start_main (main=0x4059a0 <main(int, char**)>, argc=1, argv=0x7fffffffd5e8, 
    init=0x42d3a0 <__libc_csu_init>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffd5d8) at libc-start.c:245
#8  0x00000000004057d9 in _start ()

[godbyk]

I got this sorted it. My build script was compiling against the static glog library and the dynamic gflags library.

Here are how the combinations work out:

glog  gflags  status
----  ------  ------
 so    so     OK
 so    a      error (see below)
 a     so     crash
 a     a      crash

When using the dynamic glog library and the static gflags library, the program prints the following error at runtime:

ERROR: something wrong with flag 'flagfile' in file '/home/username/git/gflags/src/gflags.cc'.  One possibility: file '/home/username/git/gflags/src/gflags.cc' is being linked both statically and dynamically into this executable.

[Shixiaowei02]

I also encountered this problem, but it seems that sometimes the results of static links are normal.

[echoface]

same problem here. libgflags.a(2.2.2) + libglog.a (0.4.0) cause crash when init LOGOBJECT, is there any root cause found about this issue?

centos and debian both, other platform not testing

log:
0x00007ffff6715c90 in std::string::c_str() const () from /lib64/libstdc++.so.6
Missing separate debuginfos, use: debuginfo-install keyutils-libs-1.5.8-3.el7.x86_64 krb5-libs-1.15.1-37.el7_7.2.x86_64 libcom_err-1.42.9-16.el7.x86_64 libgcc-4.8.5-39.el7.x86_64 libselinux-2.5-14.1.el7.x86_64 libstdc++-4.8.5-39.el7.x86_64 mariadb-libs-5.5.64-1.el7.x86_64 openssl-libs-1.0.2k-19.el7.x86_64 zlib-1.2.7-18.el7.x86_64
(gdb) bt
#0 0x00007ffff6715c90 in std::string::c_str() const () from /lib64/libstdc++.so.6
#1 0x0000000000482ac4 in google::VLOG2Initializer() ()
#2 0x0000000000482ece in google::InitVLOG3__(int**, int*, char const*, int) ()
#3 0x000000000045cfef in base::MessageLoop::ThreadMain() ()
#4 0x000000000049d2b0 in execute_native_thread_routine ()
#5 0x00007ffff7bc6e65 in start_thread () from /lib64/libpthread.so.0
#6 0x00007ffff5e7188d in clone () from /lib64/libc.so.6

[mawenge]

I declared a global variable, and in the constructor of that variable, I called glog to print logs. Then a segmentation fault occurred. In other words, the error occurred before the main method, in the constructor of the global variable.

Thread 1 "metric_test" received signal SIGSEGV, Segmentation fault.
0x00005555558e35d8 in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::size() const ()
(gdb) bt
#0  0x00005555558e35d8 in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::size() const ()
#1  0x00005555558e936e in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::empty() const ()
#2  0x0000555555aca04e in google::LogMessage::Init(char const*, int, int, void (google::LogMessage::*)()) ()
#3  0x0000555555ac985c in google::LogMessage::LogMessage(char const*, int) ()
#4  0x00007ffff72404df in data_prism::CivilToBsonDate(absl::lts_20240116::time_internal::cctz::detail::civil_time<absl::lts_20240116::time_internal::second_tag> const&, absl::lts_20240116::TimeZone const&) ()