Removed panic channel, replaced by integrated logging and issue reporting.

22 files changed, 85 insertions, 251 deletions

diff --git a/components/constellation/constellation.rs b/components/constellation/constellation.rs
index af6237ddd8b..d2152d52cfe 100644
--- a/components/constellation/constellation.rs
+++ b/components/constellation/constellation.rs
@@ -29,7 +29,6 @@ use msg::constellation_msg::{FrameId, FrameType, PipelineId};
 use msg::constellation_msg::{Key, KeyModifiers, KeyState, LoadData};
 use msg::constellation_msg::{PipelineNamespace, PipelineNamespaceId, NavigationDirection};
 use msg::constellation_msg::{SubpageId, WindowSizeType};
-use msg::constellation_msg::{self, PanicMsg};
 use net_traits::bluetooth_thread::BluetoothMethodMsg;
 use net_traits::filemanager_thread::FileManagerThreadMsg;
 use net_traits::image_cache_thread::ImageCacheThread;
@@ -91,9 +90,6 @@ pub struct Constellation<Message, LTF, STF> {
     /// A channel through which layout thread messages can be sent to this object.
     layout_sender: IpcSender<FromLayoutMsg>,
 
-    /// A channel through which panic messages can be sent to this object.
-    panic_sender: IpcSender<PanicMsg>,
-
     /// Receives messages from scripts.
     script_receiver: Receiver<FromScriptMsg>,
 
@@ -103,9 +99,6 @@ pub struct Constellation<Message, LTF, STF> {
     /// Receives messages from the layout thread
     layout_receiver: Receiver<FromLayoutMsg>,
 
-    /// Receives panic messages.
-    panic_receiver: Receiver<PanicMsg>,
-
     /// A channel (the implementation of which is port-specific) through which messages can be sent
     /// to the compositor.
     compositor_proxy: Box<CompositorProxy>,
@@ -189,9 +182,6 @@ pub struct Constellation<Message, LTF, STF> {
     /// Are we shutting down?
     shutting_down: bool,
 
-    /// Have we seen any panics? Hopefully always false!
-    handled_panic: bool,
-
     /// Have we seen any warnings? Hopefully always empty!
     /// The buffer contains `(thread_name, reason)` entries.
     handled_warnings: VecDeque<(Option<String>, String)>,
@@ -346,9 +336,10 @@ impl Log for FromScriptLogger {
 
     fn log(&self, record: &LogRecord) {
         if let Some(entry) = log_entry(record) {
-            // TODO: Store the pipeline id in TLS so we can recover it here
+            debug!("Sending log entry {:?}.", entry);
+            let pipeline_id = PipelineId::installed();
             let thread_name = thread::current().name().map(ToOwned::to_owned);
-            let msg = FromScriptMsg::LogEntry(None, thread_name, entry);
+            let msg = FromScriptMsg::LogEntry(pipeline_id, thread_name, entry);
             if let Ok(chan) = self.constellation_chan.lock() {
                 let _ = chan.send(msg);
             }
@@ -384,9 +375,10 @@ impl Log for FromCompositorLogger {
 
     fn log(&self, record: &LogRecord) {
         if let Some(entry) = log_entry(record) {
-            // TODO: Store the pipeline id in TLS so we can recover it here
+            debug!("Sending log entry {:?}.", entry);
+            let pipeline_id = PipelineId::installed();
             let thread_name = thread::current().name().map(ToOwned::to_owned);
-            let msg = FromCompositorMsg::LogEntry(None, thread_name, entry);
+            let msg = FromCompositorMsg::LogEntry(pipeline_id, thread_name, entry);
             if let Ok(chan) = self.constellation_chan.lock() {
                 let _ = chan.send(msg);
             }
@@ -430,19 +422,14 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
             let (ipc_layout_sender, ipc_layout_receiver) = ipc::channel().expect("ipc channel failure");
             let layout_receiver = ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_layout_receiver);
 
-            let (ipc_panic_sender, ipc_panic_receiver) = ipc::channel().expect("ipc channel failure");
-            let panic_receiver = ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_panic_receiver);
-
             let swmanager_receiver = ROUTER.route_ipc_receiver_to_new_mpsc_receiver(swmanager_receiver);
 
             let mut constellation: Constellation<Message, LTF, STF> = Constellation {
                 script_sender: ipc_script_sender,
                 layout_sender: ipc_layout_sender,
                 script_receiver: script_receiver,
-                panic_sender: ipc_panic_sender,
                 compositor_receiver: compositor_receiver,
                 layout_receiver: layout_receiver,
-                panic_receiver: panic_receiver,
                 compositor_proxy: state.compositor_proxy,
                 devtools_chan: state.devtools_chan,
                 bluetooth_thread: state.bluetooth_thread,
@@ -478,7 +465,6 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
                 document_states: HashMap::new(),
                 webrender_api_sender: state.webrender_api_sender,
                 shutting_down: false,
-                handled_panic: false,
                 handled_warnings: VecDeque::new(),
                 random_pipeline_closure: opts::get().random_pipeline_closure_probability.map(|prob| {
                     let seed = opts::get().random_pipeline_closure_seed.unwrap_or_else(random);
@@ -539,7 +525,6 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
             parent_info: parent_info,
             constellation_chan: self.script_sender.clone(),
             layout_to_constellation_chan: self.layout_sender.clone(),
-            panic_chan: self.panic_sender.clone(),
             scheduler_chan: self.scheduler_chan.clone(),
             compositor_proxy: self.compositor_proxy.clone_compositor_proxy(),
             devtools_chan: self.devtools_chan.clone(),
@@ -617,8 +602,7 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
             Script(FromScriptMsg),
             Compositor(FromCompositorMsg),
             Layout(FromLayoutMsg),
-            Panic(PanicMsg),
-            FromSWManager(SWManagerMsg)
+            FromSWManager(SWManagerMsg),
         }
 
         // Get one incoming request.
@@ -636,7 +620,6 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
             let receiver_from_script = &self.script_receiver;
             let receiver_from_compositor = &self.compositor_receiver;
             let receiver_from_layout = &self.layout_receiver;
-            let receiver_from_panic = &self.panic_receiver;
             let receiver_from_swmanager = &self.swmanager_receiver;
             select! {
                 msg = receiver_from_script.recv() =>
@@ -645,8 +628,6 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
                     Request::Compositor(msg.expect("Unexpected compositor channel panic in constellation")),
                 msg = receiver_from_layout.recv() =>
                     Request::Layout(msg.expect("Unexpected layout channel panic in constellation")),
-                msg = receiver_from_panic.recv() =>
-                    Request::Panic(msg.expect("Unexpected panic channel panic in constellation")),
                 msg = receiver_from_swmanager.recv() =>
                     Request::FromSWManager(msg.expect("Unexpected panic channel panic in constellation"))
             }
@@ -662,9 +643,6 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
             Request::Layout(message) => {
                 self.handle_request_from_layout(message);
             },
-            Request::Panic(message) => {
-                self.handle_request_from_panic(message);
-            },
             Request::FromSWManager(message) => {
                 self.handle_request_from_swmanager(message);
             }
@@ -957,15 +935,6 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
         }
     }
 
-    fn handle_request_from_panic(&mut self, message: PanicMsg) {
-        match message {
-            (pipeline_id, panic_reason, backtrace) => {
-                debug!("handling panic message ({:?})", pipeline_id);
-                self.handle_panic(pipeline_id, panic_reason, backtrace);
-            }
-        }
-    }
-
     fn handle_register_serviceworker(&self, scope_things: ScopeThings, scope: Url) {
         if let Some(ref mgr) = self.swmanager_chan {
             let _ = mgr.send(ServiceWorkerMsg::RegisterServiceWorker(scope_things, scope));
@@ -1053,22 +1022,14 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
     fn handle_send_error(&mut self, pipeline_id: PipelineId, err: IOError) {
         // Treat send error the same as receiving a panic message
         debug!("Pipeline {:?} send error ({}).", pipeline_id, err);
-        self.handle_panic(Some(pipeline_id), format!("Send failed ({})", err), String::from("<none>"));
+        self.handle_panic(Some(pipeline_id), format!("Send failed ({})", err), None);
     }
 
-    fn handle_panic(&mut self, pipeline_id: Option<PipelineId>, reason: String, backtrace: String) {
-        error!("Panic: {}", reason);
-        if !self.handled_panic || opts::get().full_backtraces {
-            // For the first panic, we print the full backtrace
-            error!("Backtrace:\n{}", backtrace);
-        } else {
-            error!("Backtrace skipped (run with -Z full-backtraces to see every backtrace).");
-        }
-
+    fn handle_panic(&mut self, pipeline_id: Option<PipelineId>, reason: String, backtrace: Option<String>) {
         if opts::get().hard_fail {
             // It's quite difficult to make Servo exit cleanly if some threads have failed.
             // Hard fail exists for test runners so we crash and that's good enough.
-            error!("Pipeline failed in hard-fail mode.  Crashing!");
+            println!("Pipeline failed in hard-fail mode.  Crashing!\n{}\n{}", reason, backtrace.unwrap_or_default());
             process::exit(1);
         }
 
@@ -1109,13 +1070,12 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
             self.push_pending_frame(new_pipeline_id, Some(pipeline_id));
 
         }
-
-        self.handled_panic = true;
     }
 
     fn handle_log_entry(&mut self, pipeline_id: Option<PipelineId>, thread_name: Option<String>, entry: LogEntry) {
+        debug!("Received log entry {:?}.", entry);
         match entry {
-            LogEntry::Panic(reason, backtrace) => self.trigger_mozbrowsererror(pipeline_id, reason, backtrace),
+            LogEntry::Panic(reason, backtrace) => self.handle_panic(pipeline_id, reason, Some(backtrace)),
             LogEntry::Error(reason) | LogEntry::Warn(reason) => {
                 // VecDeque::truncate is unstable
                 if WARNINGS_BUFFER_SIZE <= self.handled_warnings.len() {
@@ -1439,7 +1399,7 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
 
     fn handle_navigate_msg(&mut self,
                            pipeline_info: Option<(PipelineId, SubpageId)>,
-                           direction: constellation_msg::NavigationDirection) {
+                           direction: NavigationDirection) {
         debug!("received message to navigate {:?}", direction);
 
         // Get the frame id associated with the pipeline that sent
@@ -2310,7 +2270,7 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
 
     // https://developer.mozilla.org/en-US/docs/Web/Events/mozbrowsererror
     // Note that this does not require the pipeline to be an immediate child of the root
-    fn trigger_mozbrowsererror(&mut self, pipeline_id: Option<PipelineId>, reason: String, backtrace: String) {
+    fn trigger_mozbrowsererror(&mut self, pipeline_id: Option<PipelineId>, reason: String, backtrace: Option<String>) {
         if !PREFS.is_mozbrowser_enabled() { return; }
 
         let mut report = String::new();
@@ -2325,10 +2285,12 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
         }
         report.push_str("\nERROR: ");
         report.push_str(&*reason);
-        report.push_str("\n\n");
-        report.push_str(&*backtrace);
+        if let Some(backtrace) = backtrace {
+            report.push_str("\n\n");
+            report.push_str(&*backtrace);
+        }
 
-        let event = MozBrowserEvent::Error(MozBrowserErrorType::Fatal, Some(reason), Some(report));
+        let event = MozBrowserEvent::Error(MozBrowserErrorType::Fatal, reason, report);
 
         if let Some(pipeline_id) = pipeline_id {
             if let Some((ancestor_id, subpage_id)) = self.get_mozbrowser_ancestor_info(pipeline_id) {
diff --git a/components/constellation/pipeline.rs b/components/constellation/pipeline.rs
index 45edc40ae2a..dd2a665f6ac 100644
--- a/components/constellation/pipeline.rs
+++ b/components/constellation/pipeline.rs
@@ -17,7 +17,7 @@ use ipc_channel::ipc::{self, IpcReceiver, IpcSender};
 use ipc_channel::router::ROUTER;
 use layers::geometry::DevicePixel;
 use layout_traits::LayoutThreadFactory;
-use msg::constellation_msg::{FrameId, FrameType, LoadData, PanicMsg, PipelineId};
+use msg::constellation_msg::{FrameId, FrameType, LoadData, PipelineId};
 use msg::constellation_msg::{PipelineNamespaceId, SubpageId};
 use net_traits::bluetooth_thread::BluetoothMethodMsg;
 use net_traits::image_cache_thread::ImageCacheThread;
@@ -89,8 +89,6 @@ pub struct InitialPipelineState {
     pub constellation_chan: IpcSender<ScriptMsg>,
     /// A channel for the layout thread to send messages to the constellation.
     pub layout_to_constellation_chan: IpcSender<LayoutMsg>,
-    /// A channel to report panics
-    pub panic_chan: IpcSender<PanicMsg>,
     /// A channel to schedule timer events.
     pub scheduler_chan: IpcSender<TimerEventRequest>,
     /// A channel to the compositor.
@@ -159,7 +157,6 @@ impl Pipeline {
                     frame_type: frame_type,
                     load_data: state.load_data.clone(),
                     paint_chan: layout_to_paint_chan.clone().to_opaque(),
-                    panic_chan: state.panic_chan.clone(),
                     pipeline_port: pipeline_port,
                     layout_to_constellation_chan: state.layout_to_constellation_chan.clone(),
                     content_process_shutdown_chan: layout_content_process_shutdown_chan.clone(),
@@ -182,7 +179,6 @@ impl Pipeline {
                             layout_to_paint_port,
                             chrome_to_paint_port,
                             state.compositor_proxy.clone_compositor_proxy(),
-                            state.panic_chan.clone(),
                             state.font_cache_thread.clone(),
                             state.time_profiler_chan.clone(),
                             state.mem_profiler_chan.clone());
@@ -234,7 +230,6 @@ impl Pipeline {
                 layout_to_constellation_chan: state.layout_to_constellation_chan,
                 script_chan: script_chan.clone(),
                 load_data: state.load_data.clone(),
-                panic_chan: state.panic_chan,
                 script_port: script_port,
                 opts: (*opts::get()).clone(),
                 prefs: PREFS.cloned(),
@@ -426,7 +421,6 @@ pub struct UnprivilegedPipelineContent {
     window_size: Option<WindowSizeData>,
     script_chan: IpcSender<ConstellationControlMsg>,
     load_data: LoadData,
-    panic_chan: IpcSender<PanicMsg>,
     script_port: IpcReceiver<ConstellationControlMsg>,
     layout_to_paint_chan: OptionalIpcSender<LayoutToPaintMsg>,
     opts: Opts,
@@ -452,7 +446,6 @@ impl UnprivilegedPipelineContent {
             control_port: self.script_port,
             constellation_chan: self.constellation_chan,
             scheduler_chan: self.scheduler_chan,
-            panic_chan: self.panic_chan.clone(),
             bluetooth_thread: self.bluetooth_thread,
             resource_threads: self.resource_threads,
             image_cache_thread: self.image_cache_thread.clone(),
@@ -470,7 +463,6 @@ impl UnprivilegedPipelineContent {
                     layout_pair,
                     self.pipeline_port,
                     self.layout_to_constellation_chan,
-                    self.panic_chan,
                     self.script_chan,
                     self.layout_to_paint_chan,
                     self.image_cache_thread,
diff --git a/components/gfx/paint_thread.rs b/components/gfx/paint_thread.rs
index aa759ca6b7a..b4ad2abd299 100644
--- a/components/gfx/paint_thread.rs
+++ b/components/gfx/paint_thread.rs
@@ -17,10 +17,9 @@ use font_cache_thread::FontCacheThread;
 use font_context::FontContext;
 use gfx_traits::{ChromeToPaintMsg, Epoch, LayerId, LayerKind, LayerProperties};
 use gfx_traits::{PaintListener, PaintRequest, StackingContextId};
-use ipc_channel::ipc::IpcSender;
 use layers::layers::{BufferRequest, LayerBuffer, LayerBufferSet};
 use layers::platform::surface::{NativeDisplay, NativeSurface};
-use msg::constellation_msg::{PanicMsg, PipelineId};
+use msg::constellation_msg::PipelineId;
 use paint_context::PaintContext;
 use profile_traits::mem;
 use profile_traits::time;
@@ -377,13 +376,14 @@ impl<C> PaintThread<C> where C: PaintListener + Send + 'static {
                   layout_to_paint_port: Receiver<LayoutToPaintMsg>,
                   chrome_to_paint_port: Receiver<ChromeToPaintMsg>,
                   mut compositor: C,
-                  panic_chan: IpcSender<PanicMsg>,
                   font_cache_thread: FontCacheThread,
                   time_profiler_chan: time::ProfilerChan,
                   mem_profiler_chan: mem::ProfilerChan) {
-        thread::spawn_named_with_send_on_panic(format!("PaintThread {:?}", id),
-                                               thread_state::PAINT,
-                                               move || {
+        thread::spawn_named(format!("PaintThread {:?}", id),
+                            move || {
+            thread_state::initialize(thread_state::PAINT);
+            PipelineId::install(id);
+
             let native_display = compositor.native_display();
             let worker_threads = WorkerThreadProxy::spawn(native_display,
                                                           font_cache_thread,
@@ -412,7 +412,7 @@ impl<C> PaintThread<C> where C: PaintListener + Send + 'static {
             for worker_thread in &mut paint_thread.worker_threads {
                 worker_thread.exit()
             }
-        }, Some(id), panic_chan);
+        });
     }
 
     #[allow(unsafe_code)]
diff --git a/components/layout_thread/lib.rs b/components/layout_thread/lib.rs
index 592a6cda6a4..9d576e3bd02 100644
--- a/components/layout_thread/lib.rs
+++ b/components/layout_thread/lib.rs
@@ -76,7 +76,7 @@ use layout::traversal::RecalcStyleAndConstructFlows;
 use layout::webrender_helpers::{WebRenderDisplayListConverter, WebRenderFrameBuilder};
 use layout::wrapper::{LayoutNodeLayoutData, NonOpaqueStyleAndLayoutData};
 use layout_traits::LayoutThreadFactory;
-use msg::constellation_msg::{PanicMsg, PipelineId};
+use msg::constellation_msg::PipelineId;
 use net_traits::image_cache_thread::UsePlaceholder;
 use net_traits::image_cache_thread::{ImageCacheChan, ImageCacheResult, ImageCacheThread};
 use profile_traits::mem::{self, Report, ReportKind, ReportsChan};
@@ -244,7 +244,6 @@ impl LayoutThreadFactory for LayoutThread {
               chan: (Sender<Msg>, Receiver<Msg>),
               pipeline_port: IpcReceiver<LayoutControlMsg>,
               constellation_chan: IpcSender<ConstellationMsg>,
-              panic_chan: IpcSender<PanicMsg>,
               script_chan: IpcSender<ConstellationControlMsg>,
               paint_chan: OptionalIpcSender<LayoutToPaintMsg>,
               image_cache_thread: ImageCacheThread,
@@ -253,9 +252,10 @@ impl LayoutThreadFactory for LayoutThread {
               mem_profiler_chan: mem::ProfilerChan,
               content_process_shutdown_chan: IpcSender<()>,
               webrender_api_sender: Option<webrender_traits::RenderApiSender>) {
-        thread::spawn_named_with_send_on_panic(format!("LayoutThread {:?}", id),
-                                               thread_state::LAYOUT,
-                                               move || {
+        thread::spawn_named(format!("LayoutThread {:?}", id),
+                      move || {
+            thread_state::initialize(thread_state::LAYOUT);
+            PipelineId::install(id);
             { // Ensures layout thread is destroyed before we send shutdown message
                 let sender = chan.0;
                 let layout = LayoutThread::new(id,
@@ -278,7 +278,7 @@ impl LayoutThreadFactory for LayoutThread {
                 }, reporter_name, sender, Msg::CollectReports);
             }
             let _ = content_process_shutdown_chan.send(());
-        }, Some(id), panic_chan);
+        });
     }
 }
 
@@ -747,7 +747,6 @@ impl LayoutThread {
                              info.layout_pair,
                              info.pipeline_port,
                              info.constellation_chan,
-                             info.panic_chan,
                              info.script_chan.clone(),
                              info.paint_chan.to::<LayoutToPaintMsg>(),
                              self.image_cache_thread.clone(),
diff --git a/components/layout_traits/lib.rs b/components/layout_traits/lib.rs
index ad91999cc30..1b6c621d755 100644
--- a/components/layout_traits/lib.rs
+++ b/components/layout_traits/lib.rs
@@ -22,7 +22,7 @@ extern crate webrender_traits;
 use gfx::font_cache_thread::FontCacheThread;
 use gfx::paint_thread::LayoutToPaintMsg;
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
-use msg::constellation_msg::{PanicMsg, PipelineId};
+use msg::constellation_msg::PipelineId;
 use net_traits::image_cache_thread::ImageCacheThread;
 use profile_traits::{mem, time};
 use script_traits::LayoutMsg as ConstellationMsg;
@@ -41,7 +41,6 @@ pub trait LayoutThreadFactory {
               chan: (Sender<Self::Message>, Receiver<Self::Message>),
               pipeline_port: IpcReceiver<LayoutControlMsg>,
               constellation_chan: IpcSender<ConstellationMsg>,
-              panic_chan: IpcSender<PanicMsg>,
               script_chan: IpcSender<ConstellationControlMsg>,
               layout_to_paint_chan: OptionalIpcSender<LayoutToPaintMsg>,
               image_cache_thread: ImageCacheThread,
diff --git a/components/msg/constellation_msg.rs b/components/msg/constellation_msg.rs
index 7872e5983d2..235676f0d60 100644
--- a/components/msg/constellation_msg.rs
+++ b/components/msg/constellation_msg.rs
@@ -13,8 +13,6 @@ use std::fmt;
 use url::Url;
 use webrender_traits;
 
-pub type PanicMsg = (Option<PipelineId>, String, String);
-
 #[derive(Deserialize, Eq, PartialEq, Serialize, Copy, Clone, HeapSizeOf)]
 pub enum WindowSizeType {
     Initial,
@@ -269,6 +267,8 @@ impl PipelineNamespace {
 
 thread_local!(pub static PIPELINE_NAMESPACE: Cell<Option<PipelineNamespace>> = Cell::new(None));
 
+thread_local!(pub static PIPELINE_ID: Cell<Option<PipelineId>> = Cell::new(None));
+
 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Copy, Hash, Debug, Deserialize, Serialize, HeapSizeOf)]
 pub struct PipelineNamespaceId(pub u32);
 
@@ -308,6 +308,15 @@ impl PipelineId {
         let PipelineIndex(index) = self.index;
         webrender_traits::PipelineId(namespace_id, index)
     }
+
+    pub fn install(id: PipelineId) {
+        PIPELINE_ID.with(|tls| tls.set(Some(id)))
+    }
+
+    pub fn installed() -> Option<PipelineId> {
+        PIPELINE_ID.with(|tls| tls.get())
+    }
+
 }
 
 impl fmt::Display for PipelineId {
diff --git a/components/script/dom/bindings/global.rs b/components/script/dom/bindings/global.rs
index 5adcbb67818..fe81b8a14de 100644
--- a/components/script/dom/bindings/global.rs
+++ b/components/script/dom/bindings/global.rs
@@ -18,7 +18,7 @@ use ipc_channel::ipc::IpcSender;
 use js::jsapi::{CurrentGlobalOrNull, GetGlobalForObjectCrossCompartment};
 use js::jsapi::{JSContext, JSObject, JS_GetClass, MutableHandleValue};
 use js::{JSCLASS_IS_DOMJSCLASS, JSCLASS_IS_GLOBAL};
-use msg::constellation_msg::{PipelineId, PanicMsg};
+use msg::constellation_msg::PipelineId;
 use net_traits::filemanager_thread::FileManagerThreadMsg;
 use net_traits::{ResourceThreads, CoreResourceThread, IpcSend};
 use profile_traits::{mem, time};
@@ -283,14 +283,6 @@ impl<'a> GlobalRef<'a> {
         }
     }
 
-    /// Returns an `IpcSender` to report panics on.
-    pub fn panic_chan(&self) -> &IpcSender<PanicMsg> {
-        match *self {
-            GlobalRef::Window(ref window) => window.panic_chan(),
-            GlobalRef::Worker(ref worker) => worker.panic_chan(),
-        }
-    }
-
     /// Returns a wrapper for runnables to ensure they are cancelled if the global
     /// is being destroyed.
     pub fn get_runnable_wrapper(&self) -> RunnableWrapper {
diff --git a/components/script/dom/dedicatedworkerglobalscope.rs b/components/script/dom/dedicatedworkerglobalscope.rs
index cf5537676e0..b65fd72ab62 100644
--- a/components/script/dom/dedicatedworkerglobalscope.rs
+++ b/components/script/dom/dedicatedworkerglobalscope.rs
@@ -38,8 +38,8 @@ use std::sync::atomic::AtomicBool;
 use std::sync::mpsc::{Receiver, RecvError, Select, Sender, channel};
 use std::sync::{Arc, Mutex};
 use url::Url;
-use util::thread::spawn_named_with_send_on_panic;
-use util::thread_state::{IN_WORKER, SCRIPT};
+use util::thread::spawn_named;
+use util::thread_state;
 
 /// Set the `worker` field of a related DedicatedWorkerGlobalScope object to a particular
 /// value for the duration of this object's lifetime. This ensures that the related Worker
@@ -161,8 +161,10 @@ impl DedicatedWorkerGlobalScope {
                             closing: Arc<AtomicBool>) {
         let serialized_worker_url = worker_url.to_string();
         let name = format!("WebWorker for {}", serialized_worker_url);
-        let panic_chan = init.panic_chan.clone();
-        spawn_named_with_send_on_panic(name, SCRIPT | IN_WORKER, move || {
+        spawn_named(name, move || {
+            thread_state::initialize(thread_state::SCRIPT | thread_state::IN_WORKER);
+            PipelineId::install(id);
+
             let roots = RootCollection::new();
             let _stack_roots_tls = StackRootTLS::new(&roots);
             let (url, source) = match load_whole_resource(LoadContext::Script,
@@ -225,7 +227,7 @@ impl DedicatedWorkerGlobalScope {
                     global.handle_event(event);
                 }
             }, reporter_name, parent_sender, CommonScriptMsg::CollectReports);
-        }, Some(id.clone()), panic_chan);
+        });
     }
 
     pub fn script_chan(&self) -> Box<ScriptChan + Send> {
diff --git a/components/script/dom/htmliframeelement.rs b/components/script/dom/htmliframeelement.rs
index 1b2001c08df..efd33eecf54 100644
--- a/components/script/dom/htmliframeelement.rs
+++ b/components/script/dom/htmliframeelement.rs
@@ -353,8 +353,8 @@ unsafe fn build_mozbrowser_event_detail(event: MozBrowserEvent,
         MozBrowserEvent::Error(error_type, description, report) => {
             BrowserElementErrorEventDetail {
                 type_: Some(DOMString::from(error_type.name())),
-                description: description.map(DOMString::from),
-                report: report.map(DOMString::from),
+                description: Some(DOMString::from(description)),
+                report: Some(DOMString::from(report)),
                 version: Some(DOMString::from_string(servo_version().into())),
             }.to_jsval(cx, rval);
         },
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index 07509a92e4a..b4984bb2a4a 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -45,7 +45,7 @@ use js::jsapi::{JS_GetRuntime, JS_GC, MutableHandleValue, SetWindowProxy};
 use js::rust::CompileOptionsWrapper;
 use js::rust::Runtime;
 use libc;
-use msg::constellation_msg::{FrameType, LoadData, PanicMsg, PipelineId, SubpageId, WindowSizeType};
+use msg::constellation_msg::{FrameType, LoadData, PipelineId, SubpageId, WindowSizeType};
 use net_traits::ResourceThreads;
 use net_traits::bluetooth_thread::BluetoothMethodMsg;
 use net_traits::image_cache_thread::{ImageCacheChan, ImageCacheThread};
@@ -266,9 +266,6 @@ pub struct Window {
 
     /// A list of scroll offsets for each scrollable element.
     scroll_offsets: DOMRefCell<HashMap<UntrustedNodeAddress, Point2D<f32>>>,
-
-    #[ignore_heap_size_of = "Defined in ipc-channel"]
-    panic_chan: IpcSender<PanicMsg>,
 }
 
 impl Window {
@@ -1424,10 +1421,6 @@ impl Window {
         &self.scheduler_chan
     }
 
-    pub fn panic_chan(&self) -> &IpcSender<PanicMsg> {
-        &self.panic_chan
-    }
-
     pub fn schedule_callback(&self, callback: OneshotTimerCallback, duration: MsDuration) -> OneshotTimerHandle {
         self.timers.schedule_callback(callback,
                                       duration,
@@ -1623,7 +1616,6 @@ impl Window {
                constellation_chan: IpcSender<ConstellationMsg>,
                control_chan: IpcSender<ConstellationControlMsg>,
                scheduler_chan: IpcSender<TimerEventRequest>,
-               panic_chan: IpcSender<PanicMsg>,
                timer_event_chan: IpcSender<TimerEvent>,
                layout_chan: Sender<Msg>,
                id: PipelineId,
@@ -1693,7 +1685,6 @@ impl Window {
             ignore_further_async_events: Arc::new(AtomicBool::new(false)),
             error_reporter: error_reporter,
             scroll_offsets: DOMRefCell::new(HashMap::new()),
-            panic_chan: panic_chan,
         };
 
         WindowBinding::Wrap(runtime.cx(), win)
diff --git a/components/script/dom/workerglobalscope.rs b/components/script/dom/workerglobalscope.rs
index cd8476b49d6..154705fe145 100644
--- a/components/script/dom/workerglobalscope.rs
+++ b/components/script/dom/workerglobalscope.rs
@@ -23,7 +23,7 @@ use ipc_channel::ipc::IpcSender;
 use js::jsapi::{HandleValue, JSContext, JSRuntime};
 use js::jsval::UndefinedValue;
 use js::rust::Runtime;
-use msg::constellation_msg::{PipelineId, ReferrerPolicy, PanicMsg};
+use msg::constellation_msg::{PipelineId, ReferrerPolicy};
 use net_traits::{LoadContext, ResourceThreads, load_whole_resource};
 use net_traits::{LoadOrigin, IpcSend};
 use profile_traits::{mem, time};
@@ -58,7 +58,6 @@ pub fn prepare_workerscope_init(global: GlobalRef,
             time_profiler_chan: global.time_profiler_chan().clone(),
             from_devtools_sender: devtools_sender,
             constellation_chan: global.constellation_chan().clone(),
-            panic_chan: global.panic_chan().clone(),
             scheduler_chan: global.scheduler_chan().clone(),
             worker_id: worker_id
         };
@@ -110,9 +109,6 @@ pub struct WorkerGlobalScope {
 
     #[ignore_heap_size_of = "Defined in std"]
     scheduler_chan: IpcSender<TimerEventRequest>,
-
-    #[ignore_heap_size_of = "Defined in ipc-channel"]
-    panic_chan: IpcSender<PanicMsg>,
 }
 
 impl WorkerGlobalScope {
@@ -144,7 +140,6 @@ impl WorkerGlobalScope {
             devtools_wants_updates: Cell::new(false),
             constellation_chan: init.constellation_chan,
             scheduler_chan: init.scheduler_chan,
-            panic_chan: init.panic_chan,
         }
     }
 
@@ -221,10 +216,6 @@ impl WorkerGlobalScope {
         worker_id
     }
 
-    pub fn panic_chan(&self) -> &IpcSender<PanicMsg> {
-        &self.panic_chan
-    }
-
     pub fn get_runnable_wrapper(&self) -> RunnableWrapper {
         RunnableWrapper {
             cancelled: self.closing.clone().unwrap(),
diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index 1a32477b999..cf0cebf5a65 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -64,7 +64,7 @@ use js::jsapi::{JSTracer, SetWindowProxyClass};
 use js::jsval::UndefinedValue;
 use js::rust::Runtime;
 use mem::heap_size_of_self_and_children;
-use msg::constellation_msg::{FrameType, LoadData, PanicMsg, PipelineId, PipelineNamespace};
+use msg::constellation_msg::{FrameType, LoadData, PipelineId, PipelineNamespace};
 use msg::constellation_msg::{SubpageId, WindowSizeType, ReferrerPolicy};
 use net_traits::bluetooth_thread::BluetoothMethodMsg;
 use net_traits::image_cache_thread::{ImageCacheChan, ImageCacheResult, ImageCacheThread};
@@ -393,8 +393,6 @@ pub struct ScriptThread {
     timer_event_port: Receiver<TimerEvent>,
 
     content_process_shutdown_chan: IpcSender<()>,
-
-    panic_chan: IpcSender<PanicMsg>,
 }
 
 /// In the event of thread panic, all data on the stack runs its destructor. However, there
@@ -441,15 +439,15 @@ impl ScriptThreadFactory for ScriptThread {
     fn create(state: InitialScriptState,
               load_data: LoadData)
               -> (Sender<message::Msg>, Receiver<message::Msg>) {
-        let panic_chan = state.panic_chan.clone();
         let (script_chan, script_port) = channel();
 
         let (sender, receiver) = channel();
         let layout_chan = sender.clone();
         let pipeline_id = state.id;
-        thread::spawn_named_with_send_on_panic(format!("ScriptThread {:?}", state.id),
-                                               thread_state::SCRIPT,
-                                               move || {
+        thread::spawn_named(format!("ScriptThread {:?}", state.id),
+                            move || {
+            thread_state::initialize(thread_state::SCRIPT);
+            PipelineId::install(pipeline_id);
             PipelineNamespace::install(state.pipeline_namespace_id);
             let roots = RootCollection::new();
             let _stack_roots_tls = StackRootTLS::new(&roots);
@@ -479,7 +477,7 @@ impl ScriptThreadFactory for ScriptThread {
 
             // This must always be the very last operation performed before the thread completes
             failsafe.neuter();
-        }, Some(pipeline_id), panic_chan);
+        });
 
         (sender, receiver)
     }
@@ -592,7 +590,6 @@ impl ScriptThread {
             constellation_chan: state.constellation_chan,
             time_profiler_chan: state.time_profiler_chan,
             mem_profiler_chan: state.mem_profiler_chan,
-            panic_chan: state.panic_chan,
 
             devtools_chan: state.devtools_chan,
             devtools_port: devtools_port,
@@ -1142,7 +1139,6 @@ impl ScriptThread {
             frame_type,
             load_data,
             paint_chan,
-            panic_chan,
             pipeline_port,
             layout_to_constellation_chan,
             content_process_shutdown_chan,
@@ -1158,7 +1154,6 @@ impl ScriptThread {
             layout_pair: layout_pair,
             pipeline_port: pipeline_port,
             constellation_chan: layout_to_constellation_chan,
-            panic_chan: panic_chan,
             paint_chan: paint_chan,
             script_chan: self.control_chan.clone(),
             image_cache_thread: self.image_cache_thread.clone(),
@@ -1603,7 +1598,6 @@ impl ScriptThread {
                                  self.constellation_chan.clone(),
                                  self.control_chan.clone(),
                                  self.scheduler_chan.clone(),
-                                 self.panic_chan.clone(),
                                  ipc_timer_event_chan,
                                  incomplete.layout_chan,
                                  incomplete.pipeline_id,
diff --git a/components/script_layout_interface/message.rs b/components/script_layout_interface/message.rs
index ce97c805bb2..4fbed81429d 100644
--- a/components/script_layout_interface/message.rs
+++ b/components/script_layout_interface/message.rs
@@ -7,7 +7,7 @@ use euclid::point::Point2D;
 use euclid::rect::Rect;
 use gfx_traits::{Epoch, LayerId};
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
-use msg::constellation_msg::{PanicMsg, PipelineId};
+use msg::constellation_msg::PipelineId;
 use net_traits::image_cache_thread::ImageCacheThread;
 use profile_traits::mem::ReportsChan;
 use rpc::LayoutRPC;
@@ -145,7 +145,6 @@ pub struct NewLayoutThreadInfo {
     pub layout_pair: (Sender<Msg>, Receiver<Msg>),
     pub pipeline_port: IpcReceiver<LayoutControlMsg>,
     pub constellation_chan: IpcSender<ConstellationMsg>,
-    pub panic_chan: IpcSender<PanicMsg>,
     pub script_chan: IpcSender<ConstellationControlMsg>,
     pub image_cache_thread: ImageCacheThread,
     pub paint_chan: OptionalOpaqueIpcSender,
diff --git a/components/script_traits/lib.rs b/components/script_traits/lib.rs
index 175cc0b82f2..3b50d669b59 100644
--- a/components/script_traits/lib.rs
+++ b/components/script_traits/lib.rs
@@ -51,7 +51,7 @@ use ipc_channel::ipc::{IpcReceiver, IpcSender};
 use layers::geometry::DevicePixel;
 use libc::c_void;
 use msg::constellation_msg::{FrameId, FrameType, Image, Key, KeyModifiers, KeyState, LoadData};
-use msg::constellation_msg::{NavigationDirection, PanicMsg, PipelineId, ReferrerPolicy};
+use msg::constellation_msg::{NavigationDirection, PipelineId, ReferrerPolicy};
 use msg::constellation_msg::{PipelineNamespaceId, SubpageId, WindowSizeType};
 use net_traits::bluetooth_thread::BluetoothMethodMsg;
 use net_traits::image_cache_thread::ImageCacheThread;
@@ -142,8 +142,6 @@ pub struct NewLayoutInfo {
     pub paint_chan: OptionalOpaqueIpcSender,
     /// A port on which layout can receive messages from the pipeline.
     pub pipeline_port: IpcReceiver<LayoutControlMsg>,
-    /// A channel for sending panics on
-    pub panic_chan: IpcSender<PanicMsg>,
     /// A sender for the layout thread to communicate to the constellation.
     pub layout_to_constellation_chan: IpcSender<LayoutMsg>,
     /// A shutdown channel so that layout can tell the content process to shut down when it's done.
@@ -394,8 +392,6 @@ pub struct InitialScriptState {
     pub control_port: IpcReceiver<ConstellationControlMsg>,
     /// A channel on which messages can be sent to the constellation from script.
     pub constellation_chan: IpcSender<ScriptMsg>,
-    /// A channel for sending panics to the constellation.
-    pub panic_chan: IpcSender<PanicMsg>,
     /// A channel to schedule timer events.
     pub scheduler_chan: IpcSender<TimerEventRequest>,
     /// A channel to the resource manager thread.
@@ -471,8 +467,8 @@ pub enum MozBrowserEvent {
     /// handling `<menuitem>` element available within the browser `<iframe>`'s content.
     ContextMenu,
     /// Sent when an error occurred while trying to load content within a browser `<iframe>`.
-    /// Includes an optional human-readable description, and an optional machine-readable report.
-    Error(MozBrowserErrorType, Option<String>, Option<String>),
+    /// Includes a human-readable description, and a machine-readable report.
+    Error(MozBrowserErrorType, String, String),
     /// Sent when the favicon of a browser `<iframe>` changes.
     IconChange(String, String, String),
     /// Sent when the browser `<iframe>` has reached the server.
@@ -656,8 +652,6 @@ pub struct WorkerGlobalScopeInit {
     pub constellation_chan: IpcSender<ScriptMsg>,
     /// Message to send to the scheduler
     pub scheduler_chan: IpcSender<TimerEventRequest>,
-    /// Sender which sends panic messages
-    pub panic_chan: IpcSender<PanicMsg>,
     /// The worker id
     pub worker_id: WorkerId,
 }
diff --git a/components/servo/Cargo.lock b/components/servo/Cargo.lock
index d7eb68f237a..2134fd2d58a 100644
--- a/components/servo/Cargo.lock
+++ b/components/servo/Cargo.lock
@@ -2409,7 +2409,6 @@ name = "util"
 version = "0.0.1"
 dependencies = [
  "app_units 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "backtrace 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "getopts 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/components/servo/main.rs b/components/servo/main.rs
index 954c3f0e848..a13c2ca8b5d 100644
--- a/components/servo/main.rs
+++ b/components/servo/main.rs
@@ -26,7 +26,6 @@ extern crate backtrace;
 extern crate glutin_app as app;
 #[cfg(target_os = "android")]
 extern crate libc;
-#[cfg(target_os = "android")]
 #[macro_use]
 extern crate log;
 // The Servo engine
@@ -38,8 +37,8 @@ extern crate sig;
 use servo::Browser;
 use servo::compositing::windowing::WindowEvent;
 use servo::util::opts::{self, ArgumentParsingResult};
-use servo::util::panicking::initiate_panic_hook;
 use servo::util::servo_version;
+use std::panic;
 use std::process;
 use std::rc::Rc;
 
@@ -94,7 +93,20 @@ fn main() {
         None
     };
 
-    initiate_panic_hook();
+    // TODO: once log-panics is released, this can be replaced by
+    // log_panics::init();
+    panic::set_hook(Box::new(|info| {
+        warn!("Panic hook called.");
+        let msg = match info.payload().downcast_ref::<&'static str>() {
+            Some(s) => *s,
+            None => match info.payload().downcast_ref::<String>() {
+                Some(s) => &**s,
+                None => "Box<Any>",
+            },
+        };
+        error!("{}", msg);
+    }));
+
     setup_logging();
 
     if let Some(token) = content_process_token {
diff --git a/components/util/Cargo.toml b/components/util/Cargo.toml
index c713aac2957..e5f0bc9b5d3 100644
--- a/components/util/Cargo.toml
+++ b/components/util/Cargo.toml
@@ -11,12 +11,11 @@ path = "lib.rs"
 
 [features]
 # servo as opposed to geckolib
-servo = ["serde", "serde_macros", "backtrace", "ipc-channel", "app_units/plugins",
+servo = ["serde", "serde_macros", "ipc-channel", "app_units/plugins",
          "euclid/plugins", "euclid/unstable", "url/heap_size", "url/serde", "plugins"]
 
 [dependencies]
 app_units = "0.2.5"
-backtrace = {version = "0.2.1", optional = true}
 bitflags = "0.7"
 euclid = "0.7.1"
 getopts = "0.2.11"
diff --git a/components/util/lib.rs b/components/util/lib.rs
index 6b906f83c8d..c36ec47a4cb 100644
--- a/components/util/lib.rs
+++ b/components/util/lib.rs
@@ -3,7 +3,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #![cfg_attr(feature = "servo", feature(custom_derive))]
-#![cfg_attr(feature = "servo", feature(fnbox))]
 #![cfg_attr(feature = "servo", feature(plugin))]
 #![cfg_attr(feature = "servo", feature(reflect_marker))]
 #![cfg_attr(feature = "servo", plugin(serde_macros))]
@@ -12,7 +11,6 @@
 #![deny(unsafe_code)]
 
 extern crate app_units;
-#[cfg(feature = "servo")] extern crate backtrace;
 #[allow(unused_extern_crates)] #[macro_use] extern crate bitflags;
 extern crate euclid;
 extern crate getopts;
@@ -31,7 +29,6 @@ pub mod basedir;
 pub mod geometry;
 #[cfg(feature = "servo")] #[allow(unsafe_code)] pub mod ipc;
 #[allow(unsafe_code)] pub mod opts;
-#[cfg(feature = "servo")] pub mod panicking;
 pub mod prefs;
 pub mod resource_files;
 pub mod thread;
diff --git a/components/util/panicking.rs b/components/util/panicking.rs
deleted file mode 100644
index 20b3d002443..00000000000
--- a/components/util/panicking.rs
+++ /dev/null
@@ -1,52 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-use std::any::Any;
-use std::boxed::FnBox;
-use std::cell::RefCell;
-use std::panic::{PanicInfo, take_hook, set_hook};
-use std::sync::{Once, ONCE_INIT};
-use std::thread;
-
-// only set the panic hook once
-static HOOK_SET: Once = ONCE_INIT;
-
-/// TLS data pertaining to how failures should be reported
-pub struct PanicHandlerLocal {
-    /// failure handler passed through spawn_named_with_send_on_failure
-    pub fail: Box<FnBox(&Any)>
-}
-
-thread_local!(pub static LOCAL_INFO: RefCell<Option<PanicHandlerLocal>> = RefCell::new(None));
-
-/// Set the thread-local panic hook
-pub fn set_thread_local_hook(local: Box<FnBox(&Any)>) {
-    LOCAL_INFO.with(|i| *i.borrow_mut() = Some(PanicHandlerLocal { fail: local }));
-}
-
-/// Initiates the custom panic hook
-/// Should be called in main() after arguments have been parsed
-pub fn initiate_panic_hook() {
-    // Set the panic handler only once. It is global.
-    HOOK_SET.call_once(|| {
-        // The original backtrace-printing hook. We still want to call this
-        let hook = take_hook();
-
-        let new_hook = move |info: &PanicInfo| {
-            let payload = info.payload();
-            let name = thread::current().name().unwrap_or("<unknown thread>").to_string();
-            // Notify error handlers stored in LOCAL_INFO if any
-            LOCAL_INFO.with(|i| {
-                if let Some(local_info) = i.borrow_mut().take() {
-                    debug!("Thread `{}` failed, notifying error handlers", name);
-                    (local_info.fail).call_box((payload, ));
-                } else {
-                    hook(&info);
-                }
-            });
-        };
-        set_hook(Box::new(new_hook));
-    });
-
-}
diff --git a/components/util/thread.rs b/components/util/thread.rs
index 571d3529d9f..130187244db 100644
--- a/components/util/thread.rs
+++ b/components/util/thread.rs
@@ -2,12 +2,6 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#[cfg(feature = "servo")] use backtrace::Backtrace;
-#[cfg(feature = "servo")] use ipc_channel::ipc::IpcSender;
-#[cfg(feature = "servo")] use panicking;
-#[cfg(feature = "servo")] use serde::Serialize;
-#[cfg(feature = "servo")] use std::any::Any;
-#[cfg(feature = "servo")] use thread_state;
 use std::thread;
 
 pub fn spawn_named<F>(name: String, f: F)
@@ -15,39 +9,3 @@ pub fn spawn_named<F>(name: String, f: F)
 {
     thread::Builder::new().name(name).spawn(f).expect("Thread spawn failed");
 }
-
-/// Arrange to send a particular message to a channel if the thread fails.
-#[cfg(feature = "servo")]
-pub fn spawn_named_with_send_on_panic<F, Id>(name: String,
-                                             state: thread_state::ThreadState,
-                                             f: F,
-                                             id: Id,
-                                             panic_chan: IpcSender<(Id, String, String)>)
-    where F: FnOnce() + Send + 'static,
-          Id: Copy + Send + Serialize + 'static,
-{
-    thread::Builder::new().name(name).spawn(move || {
-        thread_state::initialize(state);
-        panicking::set_thread_local_hook(Box::new(move |payload: &Any| {
-            debug!("Thread failed, notifying constellation");
-            let reason = payload.downcast_ref::<String>().map(|s| String::from(&**s))
-                .or(payload.downcast_ref::<&'static str>().map(|s| String::from(*s)))
-                .unwrap_or_else(|| String::from("<unknown reason>"));
-            // FIXME(ajeffrey): Really we should send the backtrace itself,
-            // not just a string representation. Unfortunately we can't, because
-            // Servo won't compile backtrace with the serialize-serde feature:
-            //
-            // .../quasi_macros-0.9.0/src/lib.rs:19:29: 19:32 error: mismatched types:
-            //  expected `&mut syntex::Registry`,
-            //     found `&mut rustc_plugin::Registry<'_>`
-            // (expected struct `syntex::Registry`,
-            //     found struct `rustc_plugin::Registry`) [E0308]
-            // .../quasi_macros-0.9.0/src/lib.rs:19     quasi_codegen::register(reg);
-            //
-            // so for the moment we just send a debug string.
-            let backtrace = format!("{:?}", Backtrace::new());
-            let _ = panic_chan.send((id, reason, backtrace));
-        }));
-        f()
-    }).expect("Thread spawn failed");
-}
diff --git a/ports/cef/Cargo.lock b/ports/cef/Cargo.lock
index 591371cbfc0..558e8deab15 100644
--- a/ports/cef/Cargo.lock
+++ b/ports/cef/Cargo.lock
@@ -2278,7 +2278,6 @@ name = "util"
 version = "0.0.1"
 dependencies = [
  "app_units 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "backtrace 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "getopts 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/tests/wpt/metadata/FileAPI/blob/Blob-XHR-revoke.html.ini b/tests/wpt/metadata/FileAPI/blob/Blob-XHR-revoke.html.ini
index ffcf84dd35c..b7e66c83a20 100644
--- a/tests/wpt/metadata/FileAPI/blob/Blob-XHR-revoke.html.ini
+++ b/tests/wpt/metadata/FileAPI/blob/Blob-XHR-revoke.html.ini
@@ -1,7 +1,5 @@
 [Blob-XHR-revoke.html]
   type: testharness
-  expected: TIMEOUT
-  [Revoking blob URL used with XMLHttpRequest]
-    expected: TIMEOUT
-    bug: https://github.com/servo/servo/issues/10539
+  expected: CRASH
+  bug: https://github.com/servo/servo/issues/10539