commit c2f8006ede3d07ca53467fa73573bdbfb864a65e
author Elliott Hughes <enh@google.com> Mon Nov 07 11:57:51 2011 -0800
committer Elliott Hughes <enh@google.com> Mon Nov 07 11:57:51 2011 -0800
tree 80e24f98bbd9653790d468dcb057a6ce0016a80a
parent b1f9f22cd16929925b8330c7ee95c8a29a6e554c

Make sure that SignalCatcher says what's going on _before_ it can get stuck.

We regressed here recently. The new code is a bit neater anyway.

Change-Id: I5a786e53fc24043dce56f13357c995da6b239976

src/signal_catcher.cc

diff --git a/src/signal_catcher.cc b/src/signal_catcher.cc
index f25a9ba..d0cfe95 100644
--- a/src/signal_catcher.cc
+++ b/src/signal_catcher.cc
@@ -94,12 +94,6 @@
 void SignalCatcher::HandleSigQuit() {
   Runtime* runtime = Runtime::Current();
   ThreadList* thread_list = runtime->GetThreadList();
-  ClassLinker* class_linker = runtime->GetClassLinker();
-
-  LOG(INFO) << "Heap lock owner tid: " << Heap::GetLockOwner() << "\n"
-            << "ThreadList lock owner tid: " << thread_list->GetLockOwner() << "\n"
-            << "ClassLinker classes lock owner tid: " << class_linker->GetClassesLockOwner() << "\n"
-            << "ClassLinker dex lock owner tid: " << class_linker->GetDexLockOwner() << "\n";
 
   thread_list->SuspendAll();
 
@@ -134,8 +128,8 @@
   Heap::CollectGarbage();
 }
 
-int WaitForSignal(Thread* thread, sigset_t& mask) {
-  ScopedThreadStateChange tsc(thread, Thread::kVmWait);
+int SignalCatcher::WaitForSignal(sigset_t& mask) {
+  ScopedThreadStateChange tsc(thread_, Thread::kVmWait);
 
   // Signals for sigwait() must be blocked but not ignored.  We
   // block signals like SIGQUIT for all threads, so the condition
@@ -149,6 +143,25 @@
     PLOG(FATAL) << "sigwait failed";
   }
 
+  if (!ShouldHalt()) {
+    // Let the user know we got the signal, just in case the system's too screwed for us to
+    // actually do what they want us to do...
+    LOG(INFO) << *thread_ << ": reacting to signal " << signal_number;
+
+    // If anyone's holding locks (and so we might fail to get back into state Runnable), say so...
+    ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
+    pid_t heap_lock_owner = Heap::GetLockOwner();
+    pid_t thread_list_lock_owner = Runtime::Current()->GetThreadList()->GetLockOwner();
+    pid_t classes_lock_owner = class_linker->GetClassesLockOwner();
+    pid_t dex_lock_owner = class_linker->GetDexLockOwner();
+    if ((heap_lock_owner | thread_list_lock_owner | classes_lock_owner | dex_lock_owner) != 0) {
+      LOG(INFO) << "Heap lock owner tid: " << heap_lock_owner << "\n"
+                << "ThreadList lock owner tid: " << thread_list_lock_owner << "\n"
+                << "ClassLinker classes lock owner tid: " << classes_lock_owner << "\n"
+                << "ClassLinker dex lock owner tid: " << dex_lock_owner << "\n";
+    }
+  }
+
   return signal_number;
 }
 
@@ -173,13 +186,12 @@
   sigaddset(&mask, SIGUSR1);
 
   while (true) {
-    int signal_number = WaitForSignal(signal_catcher->thread_, mask);
+    int signal_number = signal_catcher->WaitForSignal(mask);
     if (signal_catcher->ShouldHalt()) {
       runtime->DetachCurrentThread();
       return NULL;
     }
 
-    LOG(INFO) << *signal_catcher->thread_ << ": reacting to signal " << signal_number;
     switch (signal_number) {
     case SIGQUIT:
       signal_catcher->HandleSigQuit();