From 0928de3b7becb2c03c3e57464a33ab640efbc7fe Mon Sep 17 00:00:00 2001
From: Robin Getz <rgetz503@gmail.com>
Date: Sat, 1 Aug 2026 17:06:39 -0400
Subject: [PATCH] deviceapi: Avoid iterator invalidation when clearing buddy
 lists

Fix cppcheck warning:
    Using iterator to member container 'm_sinkBuddies' that may be invalid

clearBuddiesLists() was iterating directly over m_sourceBuddies and
m_sinkBuddies while calling removeBuddy(), which modifies the buddy
relationship lists. This could invalidate the active iterator and result in
undefined behavior.

The issue could lead to intermittent failures during buddy cleanup operations,
such as device removal, device reload, or application shutdown, depending on
container state and timing.

Iterate over copies of the buddy lists so that removing relationships does not
affect the iterators used for traversal.

Signed-off-by: Robin Getz <rgetz503@gmail.com>
---
 sdrbase/device/deviceapi.cpp | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/sdrbase/device/deviceapi.cpp b/sdrbase/device/deviceapi.cpp
index d969272ba..9f6cd2921 100644
--- a/sdrbase/device/deviceapi.cpp
+++ b/sdrbase/device/deviceapi.cpp
@@ -801,32 +801,35 @@ void DeviceAPI::removeBuddy(DeviceAPI* buddy)
 
 void DeviceAPI::clearBuddiesLists()
 {
-    auto itSource = m_sourceBuddies.begin();
-    auto itSink = m_sinkBuddies.begin();
+    // Make copies before iterating because removeBuddy() modifies the buddy
+    // relationship lists. Iterating directly over m_sourceBuddies/m_sinkBuddies
+    // could invalidate iterators while the relationships are being removed.
+    auto sourceCopy = m_sourceBuddies;
+    auto sinkCopy = m_sinkBuddies;
     bool leaderElected = false;
 
-    for (;itSource != m_sourceBuddies.end(); ++itSource)
+    for (auto* buddy : sourceCopy)
     {
         if (isBuddyLeader() && !leaderElected)
         {
-            (*itSource)->setBuddyLeader(true);
+            buddy->setBuddyLeader(true);
             leaderElected = true;
         }
 
-        (*itSource)->removeBuddy(this);
+        buddy->removeBuddy(this);
     }
 
     m_sourceBuddies.clear();
 
-    for (;itSink != m_sinkBuddies.end(); ++itSink)
+    for (auto* buddy : sinkCopy)
     {
         if (isBuddyLeader() && !leaderElected)
         {
-            (*itSink)->setBuddyLeader(true);
+            buddy->setBuddyLeader(true);
             leaderElected = true;
         }
 
-        (*itSink)->removeBuddy(this);
+        buddy->removeBuddy(this);
     }
 
     m_sinkBuddies.clear();