Bug 194178 – Leak of NSArray (4.25 Kbytes) in com.apple.WebKit.WebContent running WebKit layout tests on iOS Simulator

• Component: Tools / Tests
• Status: RESOLVED FIXED

[David Kilzer (:ddkilzer)]

Leak of NSArray (4.25 Kbytes) in com.apple.WebKit.WebContent running WebKit layout tests on iOS Simulator.

NOTE: Requires patch in Bug 193772 to gather leaks for the com.apple.WebKit.WebContent.Development process.

STACK OF 664 INSTANCES OF 'ROOT LEAK: <NSArray>':
[thread 0x10f76c5c0]:
28  libdyld.dylib                         0x10c003575 start + 1
27  com.apple.WebKit.WebContent           0x10854f3e5 invocation function for block in WebKit::XPCServiceEventHandler(NSObject<OS_xpc_object>*) + 0  XPCServiceMain.mm:46
26  com.apple.WebKit.WebContent           0x10854f268 WebKit::XPCServiceMain(int, char const**) + 403  XPCServiceMain.mm:157
25  libxpc.dylib                          0x10c31cc75 xpc_main + 143
24  libxpc.dylib                          0x10c31a7ca _xpc_objc_main + 460
23  com.apple.Foundation                  0x108608522 -[NSRunLoop(NSRunLoop) run] + 76
22  com.apple.Foundation                  0x1086083b2 -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 277
21  com.apple.CoreFoundation              0x10a643e51 CFRunLoopRunSpecific + 625
20  com.apple.CoreFoundation              0x10a64467f __CFRunLoopRun + 1263
19  com.apple.CoreFoundation              0x10a649fd3 __CFRunLoopDoSources0 + 243
18  com.apple.CoreFoundation              0x10a64a761 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
17  JavaScriptCore                        0x3100d92a2 WTF::RunLoop::performWork(void*) + 34  RunLoopCF.cpp:39
16  JavaScriptCore                        0x3100d9017 WTF::RunLoop::performWork() + 231  Function.h:56
15  com.apple.WebKit                      0x108b98894 IPC::Connection::dispatchOneIncomingMessage() + 180  Connection.cpp:1074
14  com.apple.WebKit                      0x108b95262 IPC::Connection::dispatchMessage(std::__1::unique_ptr<IPC::Decoder, std::__1::default_delete<IPC::Decoder> >) + 108  memory:2567
13  com.apple.WebKit                      0x108e78ae2 WebKit::WebProcess::didReceiveMessage(IPC::Connection&, IPC::Decoder&) + 28  WebProcess.cpp:677
12  com.apple.WebKit                      0x108ba2b03 IPC::MessageReceiverMap::dispatchMessage(IPC::Connection&, IPC::Decoder&) + 127  MessageReceiverMap.cpp:0
11  com.apple.WebKit                      0x108f4d7f4 WebKit::WebPage::didReceiveWebPageMessage(IPC::Connection&, IPC::Decoder&) + 17292  tuple:170
10  com.apple.WebKit                      0x108f36db8 WebKit::WebPage::postInjectedBundleMessage(WTF::String const&, WebKit::UserData const&) + 78  utility:896
9   com.apple.WebKit                      0x108e9d299 WebKit::InjectedBundleClient::didReceiveMessageToPage(WebKit::InjectedBundle&, WebKit::WebPage&, WTF::String const&, API::Object*) + 179  RefPtr.h:43
8   WebKitTestRunnerInjectedBundle        0x321d850ec WTR::InjectedBundle::didReceiveMessageToPage(OpaqueWKBundlePage const*, OpaqueWKString const*, void const*) + 1370  InjectedBundle.cpp:0
7   WebKitTestRunnerInjectedBundle        0x321d8897d WTR::InjectedBundlePage::resetAfterTest() + 95  InjectedBundlePage.cpp:447
6   WebKitTestRunnerInjectedBundle        0x321d819ad WTR::uninstallFakeHelvetica() + 532  ActivateFontsCocoa.mm:0
5   com.apple.CoreText                    0x10d7ce946 CTFontManagerUnregisterFontsForURLs + 478
4   com.apple.CoreFoundation              0x10a632c65 +[__NSSingleObjectArrayI __new::] + 21
3   com.apple.CoreFoundation              0x10a704d11 __CFAllocateObject + 17
2   libobjc.A.dylib                       0x109be1faf class_createInstance + 73
1   libsystem_malloc.dylib                0x10c26a67d calloc + 30
0   libsystem_malloc.dylib                0x10c26a015 malloc_zone_calloc + 139 
====
    15037 (2.16M) << TOTAL >>
      ----
      28 (4.25K) ROOT LEAK: <NSArray 0x7ff65cc0e6c0> [16]
         27 (4.23K) __strong _object --> <CFError 0x7ff65cc14880> [48]
            26 (4.19K) _userInfo --> <CFDictionary 0x7ff65cc148b0> [64]
               24 (4.09K) <CFDictionary (Value Storage) 0x7ff65cc0fcc0> [32]
                  22 (4.00K) <NSMutableArray 0x7ff65cc14010> [48]
                     21 (3.95K) <NSMutableArray (Storage) 0x7ff65cc14850> [48]
                        4 (800 bytes) <NSURL 0x7ff65cc05bc0> [96]
                           2 (400 bytes) <_FileCache 0x7ff65cc0bf50> [336]
                              1 (64 bytes) <CFString 0x7ff65cc05ce0> [64]
                           1 (304 bytes) _clients --> <CFString 0x7ff65cc0aad0> [304]
                        4 (800 bytes) <NSURL 0x7ff65cc093f0> [96]
                           2 (400 bytes) <_FileCache 0x7ff65cc10e80> [336]
                              1 (64 bytes) <CFString 0x7ff65cc0f320> [64]
                           1 (304 bytes) _clients --> <CFString 0x7ff65cc0d7b0> [304]
                        4 (800 bytes) <NSURL 0x7ff65cc11450> [96]
                           2 (400 bytes) <_FileCache 0x7ff65cc11300> [336]
                              1 (64 bytes) <CFString 0x7ff65cc0fe90> [64]
                           1 (304 bytes) _clients --> <CFString 0x7ff65cc092c0> [304]
                        4 (800 bytes) <NSURL 0x7ff65cc12e20> [96]
                           2 (400 bytes) <_FileCache 0x7ff65cc12ba0> [336]
                              1 (64 bytes) <CFString 0x7ff65cc0bc90> [64]
                           1 (304 bytes) _clients --> <CFString 0x7ff65cc12cf0> [304]
                        4 (800 bytes) <NSURL 0x7ff65cc13450> [96]
                           2 (400 bytes) <_FileCache 0x7ff65cc13190> [336]
                              1 (64 bytes) <CFString 0x7ff65cc132e0> [64]
                           1 (304 bytes) _clients --> <CFString 0x7ff65cc13320> [304]
                  1 (64 bytes) <CFString 0x7ff65cc15200> [64]
               1 (32 bytes) <CFDictionary (Key Storage) 0x7ff65cc0c300> [32]

[David Kilzer (:ddkilzer)]

<rdar://problem/47753473>

[David Kilzer (:ddkilzer)]

Created attachment 360923 [details]
Patch v1

[Darin Adler]

Comment on attachment 360923 [details]
Patch v1

View in context: https://bugs.webkit.org/attachment.cgi?id=360923&action=review

> Tools/WebKitTestRunner/InjectedBundle/cocoa/ActivateFontsCocoa.mm:163
>      CFArrayRef errors = nullptr;
>      CTFontManagerUnregisterFontsForURLs(static_cast<CFArrayRef>(fontsToRemove), kCTFontManagerScopeProcess, &errors);
> +    if (errors) {
> +        for (id error in (__bridge NSArray *)errors)
> +            NSLog(@"%@", (__bridge CFErrorRef)error);
> +        CFRelease(errors);
> +    }

A better fix is to get rid of the "errors" local variable, and pass "nullptr" instead of "&errors" to CTFontManagerUnregisterFontsForURLs. Then there is no need for CFRelease. CTFontManagerUnregisterFontsForURLs won't generate an array of errors if we don’t pass a pointer to a place to put the CFArrayRef.

Also, we should not land that logging code.

[David Kilzer (:ddkilzer)]

Comment on attachment 360923 [details]
Patch v1

View in context: https://bugs.webkit.org/attachment.cgi?id=360923&action=review

>> Tools/WebKitTestRunner/InjectedBundle/cocoa/ActivateFontsCocoa.mm:163
>> +    }
> 
> A better fix is to get rid of the "errors" local variable, and pass "nullptr" instead of "&errors" to CTFontManagerUnregisterFontsForURLs. Then there is no need for CFRelease. CTFontManagerUnregisterFontsForURLs won't generate an array of errors if we don’t pass a pointer to a place to put the CFArrayRef.
> 
> Also, we should not land that logging code.

Yep, I had assumed that since Myles originally added the `errors` variable that we cared about the errors returned from CTFontManagerUnregisterFontsForURLs().

Easy enough to fix.

[David Kilzer (:ddkilzer)]

Created attachment 360964 [details]
Patch v2

[WebKit Commit Bot]

Comment on attachment 360964 [details]
Patch v2

Clearing flags on attachment: 360964

Committed r240900: <https://trac.webkit.org/changeset/240900>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.