User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:51.0) Gecko/20100101 Firefox/51.0 Build ID: 20170125094131 Steps to reproduce: I'm seeing intermittent and non-reproducible crashes of FF 51.0.0 and 51.0.1 on Linux (64 bit). I'm using builds downloaded from Mozilla, not distro versions. Actual results: Several times it has crashed with this message: [1] ###!!! ABORT: RenderFreePicture: RenderBadPicture (invalid Picture parameter): file /builds/slave/m-rel-l64-00000000000000000000/build/src/toolkit/xre/nsX11ErrorHandler.cpp, line 147 [1] ###!!! ABORT: RenderFreePicture: RenderBadPicture (invalid Picture parameter): file /builds/slave/m-rel-l64-00000000000000000000/build/src/toolkit/xre/nsX11ErrorHandler.cpp, line 147 (Yes, doubled.) The first two times that happened was upon closing a window. Later attempts to reproduce it failed, and I have also seen that crash without closing a window. Last night, left running unattended, it crashed sometime with this message: ExceptionHandler::GenerateDump cloned child 1778 ExceptionHandler::SendContinueSignalToChild sent continue signal to child ExceptionHandler::WaitForContinueSignal waiting for continue signal... Expected results: No crashes. FF49 and FF50 have been very stable for me.

Looks like the fingerprinting demo site http://www.uniquemachine.org/ can reliably crash FF51. Start with a new profile and no plug-ins/config changes different from "as shipped". Then run the fingerprint test. But it might be unrelated, since the error messages (to STDOUT / STDERR) are different: libGL error: failed to load driver: radeonsi ATTENTION: default value of option force_s3tc_enable overridden by environment. [Parent 7857] WARNING: pipe error (61): Connection reset by peer: file /builds/slave/m-rel-l64-00000000000000000000/build/src/ipc/chromium/src/chrome/common/ipc_channel_posix.cc, line 323 [Parent 7857] WARNING: pipe error (51): Connection reset by peer: file /builds/slave/m-rel-l64-00000000000000000000/build/src/ipc/chromium/src/chrome/common/ipc_channel_posix.cc, line 323 ###!!! [Parent][MessageChannel] Error: (msgtype=0x2E007F,name=PBrowser::Msg_Destroy) Channel error: cannot send/recv But I've crashed three times in minutes with that site.