Changeset 249077 in webkit

Timestamp:

Aug 23, 2019, 5:24:11 PM (7 years ago)

Author:

Chris Dumez

Message:

Crash under TimerBase::setNextFireTime() in the NetworkProcess
​https://bugs.webkit.org/show_bug.cgi?id=201097
<rdar://problem/54658339>

Reviewed by Ryosuke Niwa.

NetworkStateNotifier is a WebCore/platform class used by both WebKitLegacy and WebKit2 in the NetworkProcess.
On iOS, the lambda in the implementation of NetworkStateNotifier::startObserving() may get called by the
underlying framework on a non-main thread and we therefore want to go back to the main thread before calling
NetworkStateNotifier::singleton().updateStateSoon(). This is important because updateStateSoon() will schedule
a WebCore::Timer. The issue is that the code was using WebThreadRun() to go back the the main thread. While
this works fine in iOS WK1, it does not do what we want in WebKit2 in the network process. Indeed, before there
is no WebThread in the network process, WebThreadRun() will simply run the block on whatever thread we're one.
This would lead to crashes when trying to schedule the Timer in updateStateSoon(). To address the issue, we now
use callOnMainThread().

• platform/network/ios/NetworkStateNotifierIOS.mm:

(WebCore::NetworkStateNotifier::startObserving):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/network/ios/NetworkStateNotifierIOS.mm (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2019-08-23  Chris Dumez  <cdumez@apple.com>
+
+        Crash under TimerBase::setNextFireTime() in the NetworkProcess
+        https://bugs.webkit.org/show_bug.cgi?id=201097
+        <rdar://problem/54658339>
+
+        Reviewed by Ryosuke Niwa.
+
+        NetworkStateNotifier is a WebCore/platform class used by both WebKitLegacy and WebKit2 in the NetworkProcess.
+        On iOS, the lambda in the implementation of NetworkStateNotifier::startObserving() may get called by the
+        underlying framework on a non-main thread and we therefore want to go back to the main thread before calling
+        NetworkStateNotifier::singleton().updateStateSoon(). This is important because updateStateSoon() will schedule
+        a WebCore::Timer. The issue is that the code was using WebThreadRun() to go back the the main thread. While
+        this works fine in iOS WK1, it does not do what we want in WebKit2 in the network process. Indeed, before there
+        is no WebThread in the network process, WebThreadRun() will simply run the block on whatever thread we're one.
+        This would lead to crashes when trying to schedule the Timer in updateStateSoon(). To address the issue, we now
+        use callOnMainThread().
+
+        * platform/network/ios/NetworkStateNotifierIOS.mm:
+        (WebCore::NetworkStateNotifier::startObserving):
+
 2019-08-23  Ryosuke Niwa  <rniwa@webkit.org>
 

trunk/Source/WebCore/platform/network/ios/NetworkStateNotifierIOS.mm

@@ -85 +85 @@
         return;
     m_observer = adoptNS([[WebNetworkStateObserver alloc] initWithBlock:^ {
-        WebThreadRun(^ {
+        callOnMainThread([] {
             NetworkStateNotifier::singleton().updateStateSoon();
         });