TSAN: unprotected global counter

WARNING: ThreadSanitizer: data race (pid=1506937)
  Write of size 8 at 0x0000067ab740 by thread T6:
    #0 buf_page_get_low(page_id_t, unsigned long, unsigned long, buf_block_t*, unsigned long, mtr_t*, dberr_t*, bool) /storage/innobase/buf/buf0buf.cc:2946:8 (mariadbd+0x2014c7f)
    #1 buf_page_get_gen(page_id_t, unsigned long, unsigned long, buf_block_t*, unsigned long, mtr_t*, dberr_t*, bool) /storage/innobase/buf/buf0buf.cc:3047:10 (mariadbd+0x2016216)
    #2 btr_cur_search_to_nth_level_func(dict_index_t*, unsigned long, dtuple_t const*, page_cur_mode_t, unsigned long, btr_cur_t*, ssux_lock_impl<true>*, mtr_t*, unsigned long) /storage/innobase/btr/btr0cur.cc:1613:10 (mariadbd+0x1fb5bff)
    #3 btr_pcur_open_low(dict_index_t*, unsigned long, dtuple_t const*, page_cur_mode_t, unsigned long, btr_pcur_t*, unsigned long, mtr_t*) /storage/innobase/include/btr0pcur.ic:439:8 (mariadbd+0x24ddead)
    #4 row_search_on_row_ref(btr_pcur_t*, unsigned long, dict_table_t const*, dtuple_t const*, mtr_t*) /storage/innobase/row/row0row.cc:1215:7 (mariadbd+0x24dd537)
    #5 row_purge_reposition_pcur(unsigned long, purge_node_t*, mtr_t*) /storage/innobase/row/row0purge.cc:81:23 (mariadbd+0x24c5369)
    #6 row_purge_reset_trx_id(purge_node_t*, mtr_t*) /storage/innobase/row/row0purge.cc:748:6 (mariadbd+0x24c90c7)
    #7 row_purge_record_func(purge_node_t*, unsigned char*, que_thr_t const*, bool) /storage/innobase/row/row0purge.cc:1174:4 (mariadbd+0x24c8262)
    MariaDB#8 row_purge(purge_node_t*, unsigned char*, que_thr_t*) /storage/innobase/row/row0purge.cc:1218:18 (mariadbd+0x24c5af3)
    MariaDB#9 row_purge_step(que_thr_t*) /storage/innobase/row/row0purge.cc:1267:3 (mariadbd+0x24c5996)
    MariaDB#10 que_thr_step(que_thr_t*) /storage/innobase/que/que0que.cc:653:9 (mariadbd+0x23d5298)
    MariaDB#11 que_run_threads_low(que_thr_t*) /storage/innobase/que/que0que.cc:709:25 (mariadbd+0x23d3f29)
    MariaDB#12 que_run_threads(que_thr_t*) /storage/innobase/que/que0que.cc:729:2 (mariadbd+0x23d3bdf)
    MariaDB#13 srv_task_execute() /storage/innobase/srv/srv0srv.cc:1692:3 (mariadbd+0x2562841)
    MariaDB#14 purge_worker_callback(void*) /storage/innobase/srv/srv0srv.cc:1864:10 (mariadbd+0x255f361)
    MariaDB#15 tpool::task_group::execute(tpool::task*) /tpool/task_group.cc:55:9 (mariadbd+0x260a5ca)
    MariaDB#16 tpool::task::execute() /tpool/task.cc:47:16 (mariadbd+0x260adf6)
    MariaDB#17 tpool::thread_pool_generic::worker_main(tpool::worker_data*) /tpool/tpool_generic.cc:550:11 (mariadbd+0x25fc590)
    MariaDB#18 void std::__invoke_impl<void, void (tpool::thread_pool_generic::*)(tpool::worker_data*), tpool::thread_pool_generic*, tpool::worker_data*>(std::__invoke_memfun_deref, void (tpool::thread_pool_generic::*&&)(tpool::worker_data*), tpool::thread_pool_generic*&&, tpool::worker_data*&&) /usr/lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/invoke.h:74:14 (mariadbd+0x26061b5)
    MariaDB#19 std::__invoke_result<void (tpool::thread_pool_generic::*)(tpool::worker_data*), tpool::thread_pool_generic*, tpool::worker_data*>::type std::__invoke<void (tpool::thread_pool_generic::*)(tpool::worker_data*), tpool::thread_pool_generic*, tpool::worker_data*>(void (tpool::thread_pool_generic::*&&)(tpool::worker_data*), tpool::thread_pool_generic*&&, tpool::worker_data*&&) /usr/lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/invoke.h:96:14 (mariadbd+0x2605f57)
    MariaDB#20 void std::thread::_Invoker<std::tuple<void (tpool::thread_pool_generic::*)(tpool::worker_data*), tpool::thread_pool_generic*, tpool::worker_data*> >::_M_invoke<0ul, 1ul, 2ul>(std::_Index_tuple<0ul, 1ul, 2ul>) /usr/lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/std_thread.h:253:13 (mariadbd+0x2605ecb)
    MariaDB#21 std::thread::_Invoker<std::tuple<void (tpool::thread_pool_generic::*)(tpool::worker_data*), tpool::thread_pool_generic*, tpool::worker_data*> >::operator()() /usr/lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/std_thread.h:260:11 (mariadbd+0x2605e35)
    MariaDB#22 std::thread::_State_impl<std::thread::_Invoker<std::tuple<void (tpool::thread_pool_generic::*)(tpool::worker_data*), tpool::thread_pool_generic*, tpool::worker_data*> > >::_M_run() /usr/lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/std_thread.h:211:13 (mariadbd+0x2605ac9)
    MariaDB#23 <null> <null> (libstdc++.so.6+0xd230f)

  Previous write of size 8 at 0x0000067ab740 by thread T8:
    #0 buf_page_get_low(page_id_t, unsigned long, unsigned long, buf_block_t*, unsigned long, mtr_t*, dberr_t*, bool) /storage/innobase/buf/buf0buf.cc:2946:8 (mariadbd+0x2014c7f)
    #1 buf_page_get_gen(page_id_t, unsigned long, unsigned long, buf_block_t*, unsigned long, mtr_t*, dberr_t*, bool) /storage/innobase/buf/buf0buf.cc:3047:10 (mariadbd+0x2016216)
    #2 btr_cur_search_to_nth_level_func(dict_index_t*, unsigned long, dtuple_t const*, page_cur_mode_t, unsigned long, btr_cur_t*, ssux_lock_impl<true>*, mtr_t*, unsigned long) /storage/innobase/btr/btr0cur.cc:1613:10 (mariadbd+0x1fb5bff)
    #3 btr_pcur_open_low(dict_index_t*, unsigned long, dtuple_t const*, page_cur_mode_t, unsigned long, btr_pcur_t*, unsigned long, mtr_t*) /storage/innobase/include/btr0pcur.ic:439:8 (mariadbd+0x24ddead)
    #4 row_search_on_row_ref(btr_pcur_t*, unsigned long, dict_table_t const*, dtuple_t const*, mtr_t*) /storage/innobase/row/row0row.cc:1215:7 (mariadbd+0x24dd537)
    #5 row_purge_reposition_pcur(unsigned long, purge_node_t*, mtr_t*) /storage/innobase/row/row0purge.cc:81:23 (mariadbd+0x24c5369)
    #6 row_purge_reset_trx_id(purge_node_t*, mtr_t*) /storage/innobase/row/row0purge.cc:748:6 (mariadbd+0x24c90c7)
    #7 row_purge_record_func(purge_node_t*, unsigned char*, que_thr_t const*, bool) /storage/innobase/row/row0purge.cc:1174:4 (mariadbd+0x24c8262)
    MariaDB#8 row_purge(purge_node_t*, unsigned char*, que_thr_t*) /storage/innobase/row/row0purge.cc:1218:18 (mariadbd+0x24c5af3)
    MariaDB#9 row_purge_step(que_thr_t*) /storage/innobase/row/row0purge.cc:1267:3 (mariadbd+0x24c5996)
    MariaDB#10 que_thr_step(que_thr_t*) /storage/innobase/que/que0que.cc:653:9 (mariadbd+0x23d5298)
    MariaDB#11 que_run_threads_low(que_thr_t*) /storage/innobase/que/que0que.cc:709:25 (mariadbd+0x23d3f29)
    MariaDB#12 que_run_threads(que_thr_t*) /storage/innobase/que/que0que.cc:729:2 (mariadbd+0x23d3bdf)
    MariaDB#13 trx_purge(unsigned long, bool) /storage/innobase/trx/trx0purge.cc:1271:2 (mariadbd+0x25841b4)
    MariaDB#14 srv_do_purge(unsigned long*) /storage/innobase/srv/srv0srv.cc:1784:20 (mariadbd+0x2563224)
    MariaDB#15 purge_coordinator_callback_low() /storage/innobase/srv/srv0srv.cc:1881:35 (mariadbd+0x2562b3b)
    MariaDB#16 purge_coordinator_callback(void*) /storage/innobase/srv/srv0srv.cc:1910:3 (mariadbd+0x255f4ab)
    MariaDB#17 tpool::task_group::execute(tpool::task*) /tpool/task_group.cc:55:9 (mariadbd+0x260a5ca)
    MariaDB#18 tpool::task::execute() /tpool/task.cc:47:16 (mariadbd+0x260adf6)
    MariaDB#19 tpool::thread_pool_generic::worker_main(tpool::worker_data*) /tpool/tpool_generic.cc:550:11 (mariadbd+0x25fc590)
    MariaDB#20 void std::__invoke_impl<void, void (tpool::thread_pool_generic::*)(tpool::worker_data*), tpool::thread_pool_generic*, tpool::worker_data*>(std::__invoke_memfun_deref, void (tpool::thread_pool_generic::*&&)(tpool::worker_data*), tpool::thread_pool_generic*&&, tpool::worker_data*&&) /usr/lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/invoke.h:74:14 (mariadbd+0x26061b5)
    MariaDB#21 std::__invoke_result<void (tpool::thread_pool_generic::*)(tpool::worker_data*), tpool::thread_pool_generic*, tpool::worker_data*>::type std::__invoke<void (tpool::thread_pool_generic::*)(tpool::worker_data*), tpool::thread_pool_generic*, tpool::worker_data*>(void (tpool::thread_pool_generic::*&&)(tpool::worker_data*), tpool::thread_pool_generic*&&, tpool::worker_data*&&) /usr/lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/invoke.h:96:14 (mariadbd+0x2605f57)
    MariaDB#22 void std::thread::_Invoker<std::tuple<void (tpool::thread_pool_generic::*)(tpool::worker_data*), tpool::thread_pool_generic*, tpool::worker_data*> >::_M_invoke<0ul, 1ul, 2ul>(std::_Index_tuple<0ul, 1ul, 2ul>) /usr/lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/std_thread.h:253:13 (mariadbd+0x2605ecb)
    MariaDB#23 std::thread::_Invoker<std::tuple<void (tpool::thread_pool_generic::*)(tpool::worker_data*), tpool::thread_pool_generic*, tpool::worker_data*> >::operator()() /usr/lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/std_thread.h:260:11 (mariadbd+0x2605e35)
    MariaDB#24 std::thread::_State_impl<std::thread::_Invoker<std::tuple<void (tpool::thread_pool_generic::*)(tpool::worker_data*), tpool::thread_pool_generic*, tpool::worker_data*> > >::_M_run() /usr/lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/std_thread.h:211:13 (mariadbd+0x2605ac9)
    MariaDB#25 <null> <null> (libstdc++.so.6+0xd230f)

  Location is global 'buf_dbg_counter' of size 8 at 0x0000067ab740 (mariadbd+0x67ab740)

  The obvious fix is to make counter atomic.

storage/innobase/buf/buf0buf.cc

@@ -335,7 +335,7 @@ my_bool			buf_disable_resize_buffer_pool_debug = TRUE;
 
 /** This is used to insert validation operations in execution
 in the debug version */
-static ulint buf_dbg_counter;
+static Atomic_counter<size_t> buf_dbg_counter;
 #endif /* UNIV_DEBUG */
 
 /** Macro to determine whether the read of write counter is used depending