1 files changed, 12 insertions, 1 deletions
diff --git a/widget/android/jni/Utils.cpp b/widget/android/jni/Utils.cpp
index 8d3800fd03..78e1ab647a 100644
--- a/widget/android/jni/Utils.cpp
+++ b/widget/android/jni/Utils.cpp
@@ -9,6 +9,7 @@
 
 #include <android/log.h>
 #include <pthread.h>
+#include <sys/prctl.h>
 
 #include "mozilla/Assertions.h"
 #include "mozilla/java/GeckoAppShellWrappers.h"
@@ -164,10 +165,20 @@ JNIEnv* GetEnvForThread() {
     return env;
   }
 
+  // By default the VM has a nasty habit of overwriting our lovely
+  // thread names with "Thread-<n>" making them hard to identify in a debugger,
+  // so we pass the name in AttachArgs below to prevent that from happening.
+  // PR_GET_NAME requires a 16 byte buffer: https://linux.die.net/man/2/prctl.
+  // JNI_VERSION_1_4 is required for NewDirectByteBuffer.
+  char threadName[16] = {'\0'};
+  prctl(PR_GET_NAME, threadName);
+  JavaVMAttachArgs attachArgs{
+      .version = JNI_VERSION_1_4, .name = threadName, .group = nullptr};
+
   // We don't have a saved JNIEnv, so try to get one.
   // AttachCurrentThread() does the same thing as GetEnv() when a thread is
   // already attached, so we don't have to call GetEnv() at all.
-  if (!sJavaVM->AttachCurrentThread(&env, nullptr)) {
+  if (!sJavaVM->AttachCurrentThread(&env, &attachArgs)) {
     MOZ_ASSERT(env);
     MOZ_ALWAYS_TRUE(!pthread_setspecific(sThreadEnvKey, env));
     return env;