https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100806
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-11 branch has been updated by Thomas Rodgers <rodge...@gcc.gnu.org>: https://gcc.gnu.org/g:c24384efbbaeeca3dbc53e7d1226a57bc16e9ad5 commit r11-8638-gc24384efbbaeeca3dbc53e7d1226a57bc16e9ad5 Author: Thomas Rodgers <rodg...@appliantology.com> Date: Tue Jun 22 10:59:07 2021 -0700 libstdc++: Fix for deadlock in std::counting_semaphore [PR100806] libstdc++-v3/ChangeLog: PR libstdc++/100806 * include/bits/semaphore_base.h (__atomic_semaphore::_M_release): Force _M_release() to wake all waiting threads. * testsuite/30_threads/semaphore/100806.cc: New test. (cherry picked from commit e02840c1a92abecd211ffaf05b28329bcb534583)