[Twisted-Python] catching twisted pyqt segmentation fault

[Kevin Mcintyre]

I have a long running twisted pyqt process which occasionally throws a
Received signal 11.

I believe it's in the underlying QtWebEngineView since the twisted process
continues to run. Whatever the reason I would like to figure out a way to
catch this and stop the reactor either in process, or by another process
monitor. Any suggestions either twisted or otherwise would be greatly
appreciated.

Below is a bit of the stack trace dumped to /var/log/syslog

0x7fd855447a8f
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: 2 0x7fd855447c74
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: 3 0x7fd8555d6a82
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: 4 0x7fd8556ababd
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: 5 0x7fd8556af2f6
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: 6 0x7fd85586e52d
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: 7 0x7fd85586f511
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: 8 0x7fd85570dbc3
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: 9 0x7fd85570dd92
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: 10 0x7fd855516c0c
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: 11 0x7fd85551dacd
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: 12 0x7fd85596c5d3
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: 13 0x35946920c1fb
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: Received signal 11 SEGV_MAPERR
0000fbadbeef
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #0 0x7fd856d5ca2e <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #1 0x7fd856d5cdeb <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #2 0x7fd8526d3390 <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #3 0x7fd858404408 <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #4 0x7fd855447a8f <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #5 0x7fd855447c74 <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #6 0x7fd8555d6a82 <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #7 0x7fd8556ababd <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #8 0x7fd8556af2f6 <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #9 0x7fd85586e52d <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #10 0x7fd85586f511 <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #11 0x7fd85570dbc3 <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #12 0x7fd85570dd92 <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #13 0x7fd855516c0c <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #14 0x7fd85551dacd <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #15 0x7fd85596c5d3 <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: #16 0x35946920c1fb <unknown>
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: r8: 00007fd85a2f38c0 r9:
0000000000000013 r10: 0000000000000000 r11:
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: r12: 00007fd858aa25c8 r13:
00007fd858ab91ee r14: 00007fd85a0c9848 r15:
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: di: 0000000000000000 si:
0000000000000013 bp: 00007fd858ab91ee bx:
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: dx: 00007fd851e1d770 ax:
00000000fbadbeef cx: 00007fd851b4e6fd sp:
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: ip: 00007fd858404408 efl:
0000000000010246 cgf: 0000000000000033 erf:
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: trp: 000000000000000e msk:
0000000000000000 cr2: 00000000fbadbeef
Feb 25 22:01:32 ip-10-0-0-116 python[1836]: [end of stack trace]

[Glyph Lefkowitz]

I have a long running twisted pyqt process which occasionally throws a Received signal 11.
I believe it's in the underlying QtWebEngineView since the twisted process continues to run. Whatever the reason I would like to figure out a way to catch this and stop the reactor either in process, or by another process monitor. Any suggestions either twisted or otherwise would be greatly appreciated.

Presumably the QtWebEngineView is running a subprocess, then? This is really a Qt question rather than a Twisted question, because the QtWebEngineView should be emitting some kind of signal when its rendering process crashes. (If it doesn't I imagine you're just out of luck here and you should report a bug to the Qt developers...)

-glyph

[Kevin Mcintyre]

Thanks glyph - really appreciate all the times you've answered my questions!

QtWebEngineView is running a subprocess.

/home/ubuntu/Qt5.8.0/5.8/gcc_64/libexec/QtWebEngineProcess --type=renderer
--disable-accelerated-video-decode --disable-gpu-memory-buffer-video-frames
--enable-threaded-compositing --use-gl=desktop --disable-webrtc-hw-encoding
--primordial-pipe-token=032B94B57A61DAE34BD0F90551F9ABB6 --lang=en-US
--enable-pinch --num-raster-threads=2 --content-image-texture-target=3553

QT can sometimes be helpful, but bug resolution can take a while.

Any suggestions outside of twisted for detecting segfaults? I'm thinking
just to monitor /var/log/syslog

Post by Kevin Mcintyre

Post by Kevin Mcintyre
I have a long running twisted pyqt process which occasionally throws a

Received signal 11.

Post by Kevin Mcintyre
I believe it's in the underlying QtWebEngineView since the twisted

process continues to run. Whatever the reason I would like to figure out a
way to catch this and stop the reactor either in process, or by another
process monitor. Any suggestions either twisted or otherwise would be
greatly appreciated.
Presumably the QtWebEngineView is running a subprocess, then? This is
really a Qt question rather than a Twisted question, because the
QtWebEngineView should be emitting some kind of signal when its rendering
process crashes. (If it doesn't I imagine you're just out of luck here and
you should report a bug to the Qt developers...)
-glyph
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http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python

[Glyph Lefkowitz]

In general, detecting segfaults in arbitrary processes on the system probably isn't possible.

Specifically, I looked up the docs for you ;).

Attach a handler to the QWebEngineView::renderProcessTerminated signal :).

https://doc.qt.io/qt-5/qwebengineview.html#renderProcessTerminated <https://doc.qt.io/qt-5/qwebengineview.html#renderProcessTerminated>

Hope this helps,

-glyph

Post by Kevin Mcintyre
Thanks glyph - really appreciate all the times you've answered my questions!
QtWebEngineView is running a subprocess.
/home/ubuntu/Qt5.8.0/5.8/gcc_64/libexec/QtWebEngineProcess --type=renderer --disable-accelerated-video-decode --disable-gpu-memory-buffer-video-frames --enable-threaded-compositing --use-gl=desktop --disable-webrtc-hw-encoding --primordial-pipe-token=032B94B57A61DAE34BD0F90551F9ABB6 --lang=en-US --enable-pinch --num-raster-threads=2 --content-image-texture-target=3553
QT can sometimes be helpful, but bug resolution can take a while.
Any suggestions outside of twisted for detecting segfaults? I'm thinking just to monitor /var/log/syslog

I have a long running twisted pyqt process which occasionally throws a Received signal 11.
I believe it's in the underlying QtWebEngineView since the twisted process continues to run. Whatever the reason I would like to figure out a way to catch this and stop the reactor either in process, or by another process monitor. Any suggestions either twisted or otherwise would be greatly appreciated.

Presumably the QtWebEngineView is running a subprocess, then? This is really a Qt question rather than a Twisted question, because the QtWebEngineView should be emitting some kind of signal when its rendering process crashes. (If it doesn't I imagine you're just out of luck here and you should report a bug to the Qt developers...)
-glyph
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Twisted-Python mailing list
http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python <http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python>
_______________________________________________
Twisted-Python mailing list
http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python