Changeset 245480 in webkit

Timestamp:

May 17, 2019 2:37:07 PM (5 years ago)

Author:

beidson@apple.com

Message:

Avoid races in taking networking assertions for downloads by having both Networking and UIProcess do it.
<rdar://problem/50564630> and ​https://bugs.webkit.org/show_bug.cgi?id=197995

Reviewed by Chris Dumez.

There's a fairly indeterminant time gap between when the UIProcess decides a load becomes a download
and when the NetworkProcess Download object is created, and therefore the download assertion to be taken.

The time gap can be long enough for the Networking process to suspend before the download actually starts.

There's the reverse race when the UIProcess tells a download to stop, as well.

By having both the UIProcess and NetworkProcess take an assertion on behalf of the NetworkProcess we
avoid the race.

• NetworkProcess/Downloads/DownloadMap.cpp:

(WebKit::DownloadMap::add):
(WebKit::DownloadMap::remove):

• NetworkProcess/NetworkResourceLoader.cpp:

(WebKit::NetworkResourceLoader::convertToDownload):

• UIProcess/Downloads/DownloadProxyMap.cpp:

(WebKit::DownloadProxyMap::createDownloadProxy):
(WebKit::DownloadProxyMap::downloadFinished):
(WebKit::DownloadProxyMap::invalidate):

• UIProcess/Downloads/DownloadProxyMap.h:

Location:

trunk/Source/WebKit

Files:

• ChangeLog (modified) (1 diff)
• NetworkProcess/Downloads/DownloadMap.cpp (modified) (2 diffs)
• NetworkProcess/NetworkResourceLoader.cpp (modified) (1 diff)
• UIProcess/Downloads/DownloadProxyMap.cpp (modified) (4 diffs)
• UIProcess/Downloads/DownloadProxyMap.h (modified) (1 diff)

trunk/Source/WebKit/ChangeLog

@@ +1 @@
+2019-05-17  Brady Eidson  <beidson@apple.com>
+
+        Avoid races in taking networking assertions for downloads by having both Networking and UIProcess do it.
+        <rdar://problem/50564630> and https://bugs.webkit.org/show_bug.cgi?id=197995
+
+        Reviewed by Chris Dumez.
+
+        There's a fairly indeterminant time gap between when the UIProcess decides a load becomes a download
+        and when the NetworkProcess Download object is created, and therefore the download assertion to be taken.
+
+        The time gap can be long enough for the Networking process to suspend before the download actually starts.
+
+        There's the reverse race when the UIProcess tells a download to stop, as well.
+
+        By having both the UIProcess and NetworkProcess take an assertion on behalf of the NetworkProcess we
+        avoid the race.
+
+        * NetworkProcess/Downloads/DownloadMap.cpp:
+        (WebKit::DownloadMap::add):
+        (WebKit::DownloadMap::remove):
+
+        * NetworkProcess/NetworkResourceLoader.cpp:
+        (WebKit::NetworkResourceLoader::convertToDownload):
+
+        * UIProcess/Downloads/DownloadProxyMap.cpp:
+        (WebKit::DownloadProxyMap::createDownloadProxy):
+        (WebKit::DownloadProxyMap::downloadFinished):
+        (WebKit::DownloadProxyMap::invalidate):
+        * UIProcess/Downloads/DownloadProxyMap.h:
+
 2019-05-17  Keith Rollin  <krollin@apple.com>
 

trunk/Source/WebKit/NetworkProcess/Downloads/DownloadMap.cpp

@@ -56 +56 @@
 DownloadMap::DownloadMapType::AddResult DownloadMap::add(DownloadID downloadID, std::unique_ptr<Download>&& download)
 {
+    RELEASE_LOG(Loading, "Adding download %" PRIu64 " to NetworkProcess DownloadMap", downloadID.downloadID());
+
     auto result = m_downloads.add(downloadID, WTFMove(download));
     if (m_downloads.size() == 1) {
         ASSERT(!m_downloadAssertion);
         m_downloadAssertion = std::make_unique<ProcessAssertion>(getpid(), "WebKit downloads"_s, AssertionState::UnboundedNetworking);
+        RELEASE_LOG(ProcessSuspension, "Took 'WebKit downloads' assertion in NetworkProcess");
     }
 
@@ -67 +70 @@
 bool DownloadMap::remove(DownloadID downloadID)
 {
+    RELEASE_LOG(Loading, "Removing download %" PRIu64 " from NetworkProcess DownloadMap", downloadID.downloadID());
+
     auto result = m_downloads.remove(downloadID);
     if (m_downloads.isEmpty()) {
         ASSERT(m_downloadAssertion);
         m_downloadAssertion = nullptr;
+        RELEASE_LOG(ProcessSuspension, "Dropped 'WebKit downloads' assertion in NetworkProcess");
     }
     

trunk/Source/WebKit/NetworkProcess/NetworkResourceLoader.cpp

@@ -323 +323 @@
 void NetworkResourceLoader::convertToDownload(DownloadID downloadID, const ResourceRequest& request, const ResourceResponse& response)
 {
+    RELEASE_LOG(Loading, "Converting NetworkResourceLoader %p to download %" PRIu64 " (pageID = %" PRIu64 ", frameID = %" PRIu64 ", resourceID = %" PRIu64 ")", this, downloadID.downloadID(), m_parameters.webPageID, m_parameters.webFrameID, m_parameters.identifier);
+    
     // This can happen if the resource came from the disk cache.
     if (!m_networkLoad) {

trunk/Source/WebKit/UIProcess/Downloads/DownloadProxyMap.cpp

@@ -85 +85 @@
     m_downloads.set(downloadProxy->downloadID(), downloadProxy.copyRef());
 
+    RELEASE_LOG(Loading, "Adding download %" PRIu64 " to UIProcess DownloadProxyMap", downloadProxy->downloadID().downloadID());
+
     if (m_downloads.size() == 1 && m_shouldTakeAssertion) {
-        ASSERT(!m_downloadAssertion);
-        m_downloadAssertion = std::make_unique<ProcessAssertion>(getCurrentProcessID(), "WebKit downloads"_s, AssertionState::UnboundedNetworking);
+        ASSERT(!m_downloadUIAssertion);
+        m_downloadUIAssertion = std::make_unique<ProcessAssertion>(getCurrentProcessID(), "WebKit downloads"_s, AssertionState::UnboundedNetworking);
+
+        ASSERT(!m_downloadNetworkingAssertion);
+        RELEASE_ASSERT(m_process);
+        m_downloadNetworkingAssertion = std::make_unique<ProcessAssertion>(m_process->processIdentifier(), "WebKit downloads"_s, AssertionState::UnboundedNetworking);
+
+        RELEASE_LOG(ProcessSuspension, "UIProcess took 'WebKit downloads' assertions for UIProcess and NetworkProcess");
     }
 
@@ -99 +107 @@
     auto downloadID = downloadProxy.downloadID();
 
+    RELEASE_LOG(Loading, "Removing download %" PRIu64 " from UIProcess DownloadProxyMap", downloadID.downloadID());
+
     // The DownloadProxy may be holding the last reference to the process pool.
     auto protectedProcessPool = makeRefPtr(m_process->processPool());
@@ -109 +119 @@
 
     if (m_downloads.isEmpty() && m_shouldTakeAssertion) {
-        ASSERT(m_downloadAssertion);
-        m_downloadAssertion = nullptr;
+        ASSERT(m_downloadUIAssertion);
+        ASSERT(m_downloadNetworkingAssertion);
+        m_downloadUIAssertion = nullptr;
+        m_downloadNetworkingAssertion = nullptr;
+        RELEASE_LOG(ProcessSuspension, "UIProcess released 'WebKit downloads' assertions for UIProcess and NetworkProcess");
     }
 }
@@ -124 +137 @@
 
     m_downloads.clear();
-    m_downloadAssertion = nullptr;
+    m_downloadUIAssertion = nullptr;
+    m_downloadNetworkingAssertion = nullptr;
+    RELEASE_LOG(ProcessSuspension, "UIProcess DownloadProxyMap invalidated - Released 'WebKit downloads' assertions for UIProcess and NetworkProcess");
+
     m_process = nullptr;
 }

trunk/Source/WebKit/UIProcess/Downloads/DownloadProxyMap.h

@@ -73 +73 @@
 
     bool m_shouldTakeAssertion { false };
-    std::unique_ptr<ProcessAssertion> m_downloadAssertion;
+    std::unique_ptr<ProcessAssertion> m_downloadUIAssertion;
+    std::unique_ptr<ProcessAssertion> m_downloadNetworkingAssertion;
+
 #if PLATFORM(IOS_FAMILY)
     RetainPtr<id> m_backgroundObserver;