Changeset 251879 in webkit

Timestamp:

Oct 31, 2019 2:32:29 PM (5 years ago)

Author:

Alan Coon

Message:

Cherry-pick r251304. rdar://problem/56763315

[iOS] "Unexpectedly Resumed" process assertion may cause us to get terminated
​https://bugs.webkit.org/show_bug.cgi?id=203046
<rdar://problem/56179592>

Reviewed by Geoffrey Garen.

This patch implements the following to avoid getting terminated:

1. Schedule the task to release the assertion on a background thread instead of the main thread so that we end up releasing the task even if the main thread is somehow hung.
2. Add an invalidation handler to the process assertion which releases the assertion upon expiration.

• UIProcess/Cocoa/WebProcessProxyCocoa.mm: (WebKit::WebProcessProxy::processWasUnexpectedlyUnsuspended):
• WebProcess/WebProcess.cpp: (WebKit::WebProcess::processDidResume):
• WebProcess/WebProcess.h:
• WebProcess/cocoa/WebProcessCocoa.mm: (WebKit::WebProcess::processTaskStateDidChange):

git-svn-id: ​https://svn.webkit.org/repository/webkit/trunk@251304 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Location:

branches/safari-608.3.10.0-branch/Source/WebKit

Files:

• ChangeLog (modified) (1 diff)
• UIProcess/Cocoa/WebProcessProxyCocoa.mm (modified) (1 diff)
• WebProcess/WebProcess.cpp (modified) (1 diff)
• WebProcess/WebProcess.h (modified) (2 diffs)
• WebProcess/cocoa/WebProcessCocoa.mm (modified) (1 diff)

branches/safari-608.3.10.0-branch/Source/WebKit/ChangeLog

@@ +1 @@
+2019-10-31  Alan Coon  <alancoon@apple.com>
+
+        Cherry-pick r251304. rdar://problem/56763315
+
+    [iOS] "Unexpectedly Resumed" process assertion may cause us to get terminated
+    https://bugs.webkit.org/show_bug.cgi?id=203046
+    <rdar://problem/56179592>
+    
+    Reviewed by Geoffrey Garen.
+    
+    This patch implements the following to avoid getting terminated:
+    1. Schedule the task to release the assertion on a background thread instead of
+       the main thread so that we end up releasing the task even if the main thread
+       is somehow hung.
+    2. Add an invalidation handler to the process assertion which releases the assertion
+       upon expiration.
+    
+    * UIProcess/Cocoa/WebProcessProxyCocoa.mm:
+    (WebKit::WebProcessProxy::processWasUnexpectedlyUnsuspended):
+    * WebProcess/WebProcess.cpp:
+    (WebKit::WebProcess::processDidResume):
+    * WebProcess/WebProcess.h:
+    * WebProcess/cocoa/WebProcessCocoa.mm:
+    (WebKit::WebProcess::processTaskStateDidChange):
+    
+    
+    git-svn-id: https://svn.webkit.org/repository/webkit/trunk@251304 268f45cc-cd09-0410-ab3c-d52691b4dbfc
+
+    2019-10-18  Chris Dumez  <cdumez@apple.com>
+
+            [iOS] "Unexpectedly Resumed" process assertion may cause us to get terminated
+            https://bugs.webkit.org/show_bug.cgi?id=203046
+            <rdar://problem/56179592>
+
+            Reviewed by Geoffrey Garen.
+
+            This patch implements the following to avoid getting terminated:
+            1. Schedule the task to release the assertion on a background thread instead of
+               the main thread so that we end up releasing the task even if the main thread
+               is somehow hung.
+            2. Add an invalidation handler to the process assertion which releases the assertion
+               upon expiration.
+
+            * UIProcess/Cocoa/WebProcessProxyCocoa.mm:
+            (WebKit::WebProcessProxy::processWasUnexpectedlyUnsuspended):
+            * WebProcess/WebProcess.cpp:
+            (WebKit::WebProcess::processDidResume):
+            * WebProcess/WebProcess.h:
+            * WebProcess/cocoa/WebProcessCocoa.mm:
+            (WebKit::WebProcess::processTaskStateDidChange):
+
 2019-10-15  Alan Coon  <alancoon@apple.com>
 

branches/safari-608.3.10.0-branch/Source/WebKit/UIProcess/Cocoa/WebProcessProxyCocoa.mm

@@ -195 +195 @@
     if (m_throttler.shouldBeRunnable()) {
         // The process becoming unsuspended was not unexpected; it likely was notified of its running state
-        // before receiving a procsessDidResume() message from the UIProcess.
+        // before receiving a processDidResume() message from the UIProcess.
         return;
     }

branches/safari-608.3.10.0-branch/Source/WebKit/WebProcess/WebProcess.cpp

@@ -1635 +1635 @@
     SQLiteDatabase::setIsDatabaseOpeningForbidden(false);
     accessibilityProcessSuspendedNotification(false);
+    {
+        LockHolder holder(m_unexpectedlyResumedUIAssertionLock);
+        m_unexpectedlyResumedUIAssertion = nullptr;
+    }
 #endif
 

branches/safari-608.3.10.0-branch/Source/WebKit/WebProcess/WebProcess.h

@@ -63 +63 @@
 #if PLATFORM(IOS_FAMILY)
 #include "ProcessTaskStateObserver.h"
+OBJC_CLASS BKSProcessAssertion;
 #endif
 
@@ -531 +532 @@
     WebSQLiteDatabaseTracker m_webSQLiteDatabaseTracker;
     Ref<ProcessTaskStateObserver> m_taskStateObserver;
+    Lock m_unexpectedlyResumedUIAssertionLock;
+    RetainPtr<BKSProcessAssertion> m_unexpectedlyResumedUIAssertion;
 #endif
 

branches/safari-608.3.10.0-branch/Source/WebKit/WebProcess/cocoa/WebProcessCocoa.mm

@@ -312 +312 @@
         return;
 
+    LockHolder holder(m_unexpectedlyResumedUIAssertionLock);
+    if (m_unexpectedlyResumedUIAssertion)
+        return;
+
     // We were awakened from suspension unexpectedly. Notify the WebProcessProxy, but take a process assertion on our parent PID
     // to ensure that it too is awakened.
-
-    auto uiProcessAssertion = adoptNS([[BKSProcessAssertion alloc] initWithPID:parentProcessConnection()->remoteProcessID() flags:BKSProcessAssertionPreventTaskSuspend reason:BKSProcessAssertionReasonFinishTask name:@"Unexpectedly resumed" withHandler:nil]);
+    m_unexpectedlyResumedUIAssertion = adoptNS([[BKSProcessAssertion alloc] initWithPID:parentProcessConnection()->remoteProcessID() flags:BKSProcessAssertionPreventTaskSuspend reason:BKSProcessAssertionReasonFinishTask name:@"Unexpectedly resumed" withHandler:nil]);
+
+    auto releaseAssertion = [this] {
+        LockHolder holder(m_unexpectedlyResumedUIAssertionLock);
+        if (!m_unexpectedlyResumedUIAssertion)
+            return;
+
+        [m_unexpectedlyResumedUIAssertion invalidate];
+        m_unexpectedlyResumedUIAssertion = nullptr;
+    };
+
+    m_unexpectedlyResumedUIAssertion.get().invalidationHandler = releaseAssertion;
     parentProcessConnection()->send(Messages::WebProcessProxy::ProcessWasUnexpectedlyUnsuspended(), 0);
-    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(5 * NSEC_PER_SEC)), dispatch_get_main_queue(), [assertion = WTFMove(uiProcessAssertion)] { [assertion invalidate]; });
+    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(5 * NSEC_PER_SEC)), dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), releaseAssertion);
 }
 #endif