From: Martin Kroeker <martin@ruby.chemie.uni-freiburg.de>
Date: Fri, 7 Mar 2025 12:48:28 +0000 (+0100)
Subject: [PATCH] Improve thread safety of pthreads builds that rely on C11 atomic operations... 
X-Git-Tag: archive/raspbian/0.3.29+ds-3+rpi1^2~7
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=e41c6c230c32fc3c8896ac3916e5544bcf0552f1;p=openblas.git

[PATCH] Improve thread safety of pthreads builds that rely on C11 atomic operations for locking (#5170)

* Tighten memory orders for C11 atomic operations

Gbp-Pq: Name 39eb43d4410d0745ca2c78d1162d973abf3aa35b.patch
---

diff --git a/driver/others/blas_server.c b/driver/others/blas_server.c
index 7306a3e..4b79136 100644
--- a/driver/others/blas_server.c
+++ b/driver/others/blas_server.c
@@ -146,8 +146,8 @@ typedef struct {
 } thread_status_t;
 
 #ifdef HAVE_C11
-#define	atomic_load_queue(p)		__atomic_load_n(p, __ATOMIC_RELAXED)
-#define	atomic_store_queue(p, v)	__atomic_store_n(p, v, __ATOMIC_RELAXED)
+#define	atomic_load_queue(p)		__atomic_load_n(p, __ATOMIC_ACQUIRE)
+#define	atomic_store_queue(p, v)	__atomic_store_n(p, v, __ATOMIC_RELEASE)
 #else
 #define	atomic_load_queue(p)		(blas_queue_t*)(*(volatile blas_queue_t**)(p))
 #define	atomic_store_queue(p, v)	(*(volatile blas_queue_t* volatile*)(p) = (v))
@@ -637,7 +637,9 @@ int exec_blas_async(BLASLONG pos, blas_queue_t *queue){
 
 #ifdef SMP_SERVER
   // Handle lazy re-init of the thread-pool after a POSIX fork
+  LOCK_COMMAND(&server_lock);
   if (unlikely(blas_server_avail == 0)) blas_thread_init();
+  UNLOCK_COMMAND(&server_lock);
 #endif
   BLASLONG i = 0;
   blas_queue_t *current = queue;