138971 2014-11-21 10:38:37 -0800 [iOS] allocate volume view on the main thread 2015-06-18 10:00:12 -0700 1 1 1 Unclassified WebKit Media 528+ (Nightly build) Unspecified Unspecified RESOLVED FIXED https://bugs.webkit.org/show_bug.cgi?id=142970 InRadar P2 Normal --- 1 eric.carlson eric.carlson commit-queue danielo danny.zlobinsky glenn icloutier jer.noble philipj sergio oldest_to_newest 1050489 0 eric.carlson 2014-11-21 10:38:37 -0800 The volume view used to check for wireless target availability should be allocated on the main thread. 1050508 1 eric.carlson 2014-11-21 11:04:34 -0800 rdar://problem/18016958 1050509 2 242053 eric.carlson 2014-11-21 11:07:51 -0800 Created attachment 242053 Proposed patch. 1050551 3 242053 commit-queue 2014-11-21 13:22:35 -0800 Comment on attachment 242053 Proposed patch. Clearing flags on attachment: 242053 Committed r176471: <http://trac.webkit.org/changeset/176471> 1050552 4 commit-queue 2014-11-21 13:22:42 -0800 All reviewed patches have been landed. Closing bug. 1050947 5 eric.carlson 2014-11-24 20:42:09 -0800 *** Bug 138961 has been marked as a duplicate of this bug. *** 1051170 6 danielo 2014-11-27 07:07:21 -0800 This fix is not good. It deadlocks the app if the main thread is doing something related to the web view, because at the time of . We're getting this freeze quite often, and get different stacks in the main thread, ending with: thread #1: tid = 0x10919d, 0x33473ba8 libsystem_kernel.dylib`__psynch_mutexwait + 24, queue = 'com.apple.main-thread', stop reason = signal SIGSTOP * frame #0: 0x33473ba8 libsystem_kernel.dylib`__psynch_mutexwait + 24 frame #1: 0x334f103a libsystem_pthread.dylib`_pthread_mutex_lock + 394 frame #2: 0x307fdf20 WebCore`_WebTryThreadLock(bool) + 44 frame #3: 0x307fe736 WebCore`WebThreadLock + 82 While the WebThread will wait on dispatch_sync(dispatch_get_main_queue(), ...). The web thread is running, and locked so the main thread can't proceed to lock. The web thread can't proceed, with dispatch_sync, because the main thread is busy. Try using dispatch_async instead. This should do the trick if the _volumeView is not going to be used immediately in the WebThread. 1051736 7 eric.carlson 2014-12-01 21:43:09 -0800 (In reply to comment #6) > This fix is not good. It deadlocks the app if the main thread is doing > something related to the web view, because at the time of . > > We're getting this freeze quite often, and get different stacks in the main > thread, ending with: > > thread #1: tid = 0x10919d, 0x33473ba8 > libsystem_kernel.dylib`__psynch_mutexwait + 24, queue = > 'com.apple.main-thread', stop reason = signal SIGSTOP > * frame #0: 0x33473ba8 libsystem_kernel.dylib`__psynch_mutexwait + 24 > frame #1: 0x334f103a libsystem_pthread.dylib`_pthread_mutex_lock + 394 > frame #2: 0x307fdf20 WebCore`_WebTryThreadLock(bool) + 44 > frame #3: 0x307fe736 WebCore`WebThreadLock + 82 > > While the WebThread will wait on dispatch_sync(dispatch_get_main_queue(), > ...). The web thread is running, and locked so the main thread can't proceed > to lock. The web thread can't proceed, with dispatch_sync, because the main > thread is busy. > > Try using dispatch_async instead. This should do the trick if the > _volumeView is not going to be used immediately in the WebThread. Thank you for the information. Please feel free to submit patches if you have suggestions for changes. 1079426 8 icloutier 2015-03-23 14:19:05 -0700 UIWebView frequently crashes on iOS because of this bug and the proposed patch does not fix the problem. A reproducible example has been provided with rdar://problem/18609955 The allocateVolumeView method checks for isMainThread() which is implemented as: (isWebThread() || pthread_main_np()) Since this is called from the web thread, isMainThread returns true. Also, MPVolumeView gets allocated twice in the case where isMainThread() is false. Once on the main thread and then another time on the background thread (which is what we are trying to avoid here). 242053 2014-11-21 11:07:51 -0800 2014-11-21 13:22:35 -0800 Proposed patch. volume_view_patch_1.txt text/plain 3765 eric.carlson SW5kZXg6IFNvdXJjZS9XZWJDb3JlL0NoYW5nZUxvZwo9PT09PT09PT09PT09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09Ci0tLSBTb3VyY2UvV2Vi Q29yZS9DaGFuZ2VMb2cJKHJldmlzaW9uIDE3NjQ1MikKKysrIFNvdXJjZS9XZWJDb3JlL0NoYW5n ZUxvZwkod29ya2luZyBjb3B5KQpAQCAtMSwzICsxLDE2IEBACisyMDE0LTExLTIxICBFcmljIENh cmxzb24gIDxlcmljLmNhcmxzb25AYXBwbGUuY29tPgorCisgICAgICAgIFtpT1NdIGFsbG9jYXRl IHZvbHVtZSB2aWV3IG9uIHRoZSBtYWluIHRocmVhZAorICAgICAgICBodHRwczovL2J1Z3Mud2Vi a2l0Lm9yZy9zaG93X2J1Zy5jZ2k/aWQ9MTM4OTcxCisgICAgICAgIHJkYXI6Ly9wcm9ibGVtLzE4 MDE2OTU4CisKKyAgICAgICAgUmV2aWV3ZWQgYnkgTk9CT0RZIChPT1BTISkuCisKKyAgICAgICAg KiBwbGF0Zm9ybS9hdWRpby9pb3MvTWVkaWFTZXNzaW9uTWFuYWdlcklPUy5tbToKKyAgICAgICAg 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