Merge pull request #1460 from pguyot/w02/fix-race-condition-in-timeout

Fix race condition in timeout handling

These changes are made under both the "Apache 2.0" and the "GNU Lesser General
Public License 2.1 or later" license terms (dual license).

SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later

Author: bettio

CHANGELOG.md

@@ -27,6 +27,7 @@ certain VM instructions are used.
 - Fixed an issue where a timeout would occur immediately in a race condition
 - Fixed SPI close command
 - Added missing lock on socket structure
+- Fixed a race condition affecting multi-core MCUs where a timeout would not be properly cleared
 
 ## [0.6.5] - 2024-10-15
 

src/libAtomVM/scheduler.c

@@ -414,11 +414,11 @@ void scheduler_cancel_timeout(Context *ctx)
 {
     GlobalContext *glb = ctx->global;
 
-    context_update_flags(ctx, ~(WaitingTimeout | WaitingTimeoutExpired), NoFlags);
-
     struct TimerList *tw = &glb->timer_list;
 
     SMP_SPINLOCK_LOCK(&glb->timer_spinlock);
     timer_list_remove(tw, &ctx->timer_list_head);
     SMP_SPINLOCK_UNLOCK(&glb->timer_spinlock);
+
+    context_update_flags(ctx, ~(WaitingTimeout | WaitingTimeoutExpired), NoFlags);
 }