Created attachment 297096 [details] Crash log Intermittent crash seen during perf test IndexedDB/objectstore-get.html https://build.webkit.org/builders/Apple%20Yosemite%20Release%20WK2%20%28Perf%29/builds/6861/steps/perf-test/logs/stdio Thread 2 Crashed:: Dispatch queue: com.apple.IPC.ReceiveQueue 0 com.apple.WebKit 0x00000001022b56db IPC::Connection::sendMessage(std::__1::unique_ptr<IPC::MachMessage, std::__1::default_delete<IPC::MachMessage> >) + 27 1 com.apple.WebKit 0x00000001022b5a2a ___ZN3IPC10Connection20initializeSendSourceEv_block_invoke + 77 2 libdispatch.dylib 0x00007fff911bfe73 _dispatch_client_callout + 8 3 libdispatch.dylib 0x00007fff911cc4e6 _dispatch_source_latch_and_call + 721 4 libdispatch.dylib 0x00007fff911c493b _dispatch_source_invoke + 412 5 libdispatch.dylib 0x00007fff911c33bc _dispatch_queue_drain + 571 6 libdispatch.dylib 0x00007fff911c3030 _dispatch_queue_invoke + 202 7 libdispatch.dylib 0x00007fff911c2bef _dispatch_root_queue_drain + 463 8 libdispatch.dylib 0x00007fff911c2a1c _dispatch_worker_thread3 + 91 9 libsystem_pthread.dylib 0x00007fff8de66a9d _pthread_wqthread + 729 10 libsystem_pthread.dylib 0x00007fff8de643dd start_wqthread + 13
Still seeing this crash frequently on perf tests. IndexedDB/objectstore-cursor.html crashed on this run: https://build.webkit.org/builders/Apple%20El%20Capitan%20Release%20WK2%20%28Perf%29/builds/3896/steps/perf-test/logs/stdio
<rdar://problem/29757269>
Seen here with LayoutTest accessibility/text-marker/character-offset-visible-position-conversion-hang.html: https://build.webkit.org/results/Apple%20El%20Capitan%20Release%20WK2%20(Tests)/r210038%20(11960)/results.html
Started on 2016-12-09, and still happening.
We are not getting the logging added in http://trac.webkit.org/r209831. I don't think that we are taking the code path that logging got added to. The crash is a segfault, not a trap.
It seems to be crashing on message->size(), because message is a null pointer.
Created attachment 298611 [details] Patch
Comment on attachment 298611 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=298611&action=review > Source/WebKit2/Platform/IPC/mac/ConnectionMac.mm:403 > + // FIXME: Figure out why we get spurious DISPATCH_MACH_SEND_POSSIBLE events. Is there any logging we can add now to help diagnose?
Committed r210596: <http://trac.webkit.org/changeset/210596>