Merge pull request #13251 from omoerbeek/mtasker-exception-fiber

rec: When an exception is thrown from an mthread register stack switch (in the ASAN case)
PowerDNS · Sep 13, 2023 · 7a54e86 · 7a54e86
2 parents 89209f0 + c3b9a89
commit 7a54e86
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Showing 3 changed files with 24 additions and 18 deletions.
diff --git a/pdns/mtasker.cc b/pdns/mtasker.cc
@@ -252,7 +252,13 @@ template<class EventKey, class EventVal, class Cmp>int MTasker<EventKey,EventVal
   auto userspace=std::move(waiter->context);
   d_waiters.erase(waiter);             // removes the waitpoint
   notifyStackSwitch(d_threads[d_tid].startOfStack, d_stacksize);
-  pdns_swapcontext(d_kernel,*userspace); // swaps back to the above point 'A'
+  try {
+    pdns_swapcontext(d_kernel,*userspace); // swaps back to the above point 'A'
+  }
+  catch (...) {
+    notifyStackSwitchDone();
+    throw;
+  }
   notifyStackSwitchDone();
   return 1;
 }
@@ -325,7 +331,14 @@ template<class Key, class Val, class Cmp>bool MTasker<Key,Val,Cmp>::schedule(con
     d_threads[d_tid].dt.start();
 #endif
     notifyStackSwitch(d_threads[d_tid].startOfStack, d_stacksize);
-    pdns_swapcontext(d_kernel, *d_threads[d_tid].context);
+    try {
+      pdns_swapcontext(d_kernel, *d_threads[d_tid].context);
+    }
+    catch (...) {
+      notifyStackSwitchDone();
+      // It is not clear if the d_runQueue.pop() should be done in this case
+      throw;
+    }
     notifyStackSwitchDone();
 
     d_runQueue.pop();
@@ -367,7 +380,13 @@ template<class Key, class Val, class Cmp>bool MTasker<Key,Val,Cmp>::schedule(con
         ttdindex.erase(i++);                  // removes the waitpoint
 
         notifyStackSwitch(d_threads[d_tid].startOfStack, d_stacksize);
-        pdns_swapcontext(d_kernel, *uc); // swaps back to the above point 'A'
+        try {
+          pdns_swapcontext(d_kernel, *uc); // swaps back to the above point 'A'
+        }
+        catch (...) {
+          notifyStackSwitchDone();
+          throw;
+        }
         notifyStackSwitchDone();
       }
       else if(i->ttd.tv_sec)

diff --git a/pdns/recursordist/test-mtasker.cc b/pdns/recursordist/test-mtasker.cc
@@ -78,19 +78,6 @@ BOOST_AUTO_TEST_CASE(test_AlmostStackOverflow)
   BOOST_CHECK_EQUAL(g_result, o);
 }
 
-#if defined(HAVE_FIBER_SANITIZER) && defined(__APPLE__) && defined(__arm64__)
-
-// This test is buggy on MacOS when compiled with asan. It also causes subsequents tests to report spurious issues.
-// So switch it off for now
-// See https://github.com/PowerDNS/pdns/issues/12151
-
-BOOST_AUTO_TEST_CASE(test_MtaskerException)
-{
-  cerr << "test_MtaskerException test disabled on this platform with asan enabled, please fix" << endl;
-}
-
-#else
-
 static void willThrow(void* /* p */)
 {
   throw std::runtime_error("Help!");
@@ -111,6 +98,4 @@ BOOST_AUTO_TEST_CASE(test_MtaskerException)
                     std::exception);
 }
 
-#endif // defined(HAVE_FIBER_SANITIZER) && defined(__APPLE__) && defined(__arm64__)
-
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/pdns/recursordist/test-rec-zonetocache.cc b/pdns/recursordist/test-rec-zonetocache.cc
@@ -169,6 +169,8 @@ static void zonemdGenericTest(const std::string& lines, pdns::ZoneMD::Config mod
 
 BOOST_AUTO_TEST_CASE(test_zonetocachegeneric)
 {
+  g_log.setLoglevel(Logger::Critical);
+  g_log.toConsole(Logger::Critical);
   zonemdGenericTest(genericTest, pdns::ZoneMD::Config::Require, pdns::ZoneMD::Config::Ignore, 4U);
   zonemdGenericTest(genericBadTest, pdns::ZoneMD::Config::Require, pdns::ZoneMD::Config::Ignore, 0U);
 }