From e57bc91775ee4a888a4f11908cbd72ceadbd2ae5 Mon Sep 17 00:00:00 2001 From: Greg Burd Date: Thu, 12 Nov 2026 12:12:40 -0500 Subject: [PATCH v4 07/21] port: Fix two bugs in the native Windows pg_threads.h mapping. pg_cnd_timedwait() reported a timeout as an error, because the SleepConditionVariable*() functions fail with ERROR_TIMEOUT, while pg_thrd_map_windows_error() only recognized WAIT_TIMEOUT, which is what the WaitFor*() functions return. Map both to pg_thrd_timedout. test_pg_threads found this when built with PG_THREADS_USE_WINDOWS_H. pg_tss_ensure_fls_registered() checked pg_tss_fls without holding the lock, which is a data race, and it returned an uninitialized result when FlsAlloc() failed. Allocate the index with pg_call_once() instead, keeping the error code for the failure report. A failure is now remembered rather than retried, which seems fine for running out of FLS indexes. --- src/port/pg_threads.c | 35 ++++++++++++----------------------- 1 file changed, 12 insertions(+), 23 deletions(-) diff --git a/src/port/pg_threads.c b/src/port/pg_threads.c index 3c0b1a2aeaa..292771c94aa 100644 --- a/src/port/pg_threads.c +++ b/src/port/pg_threads.c @@ -142,6 +142,7 @@ pg_thrd_map_windows_error(DWORD windows_error) return pg_thrd_nomem; case ERROR_BUSY: return pg_thrd_busy; + case ERROR_TIMEOUT: case WAIT_TIMEOUT: return pg_thrd_timedout; default: @@ -306,6 +307,8 @@ static thread_local pg_thrd_t pg_thrd_current_thread_local; static thread_local pg_tss_value pg_tss_values[PG_TSS_MAX]; static pg_tss_slot pg_tss_slots[PG_TSS_MAX]; static DWORD pg_tss_fls = FLS_OUT_OF_INDEXES; +static DWORD pg_tss_fls_error; +static pg_once_flag pg_tss_fls_once = PG_ONCE_FLAG_INIT; static pg_mtx_t pg_tss_lock = PG_MTX_PLAIN_INIT; static BOOL CALLBACK @@ -623,28 +626,12 @@ pg_tss_fls_destructor(void *data) } } -static bool -pg_tss_ensure_fls_registered(void) +static void +pg_tss_register_fls(void) { - bool success; - - if (pg_tss_fls != FLS_OUT_OF_INDEXES) - return true; /* fast exit, already set */ - - pg_mtx_lock(&pg_tss_lock); - if (pg_tss_fls != FLS_OUT_OF_INDEXES) - { - success = true; - } - else - { - pg_tss_fls = FlsAlloc(pg_tss_fls_destructor); - if (pg_tss_fls != FLS_OUT_OF_INDEXES) - success = true; - } - pg_mtx_unlock(&pg_tss_lock); - - return success; + pg_tss_fls = FlsAlloc(pg_tss_fls_destructor); + if (pg_tss_fls == FLS_OUT_OF_INDEXES) + pg_tss_fls_error = GetLastError(); } int @@ -652,8 +639,10 @@ pg_tss_create_impl(pg_tss_t *id, pg_tss_dtor_t dtor) { bool created = false; - if (!pg_tss_ensure_fls_registered()) - return pg_thrd_map_windows_error(GetLastError()); + /* Allocate the FLS index that runs our destructors, on first use. */ + pg_call_once(&pg_tss_fls_once, pg_tss_register_fls); + if (pg_tss_fls == FLS_OUT_OF_INDEXES) + return pg_thrd_map_windows_error(pg_tss_fls_error); pg_mtx_lock(&pg_tss_lock); for (int i = 0; i < lengthof(pg_tss_slots); ++i) -- 2.54.0