webrtc/datachannel/basic-tcp.html will crash with an invalid crash

• Component: New Bugs
• Status: RESOLVED FIXED

[Matt Lewis]

webrtc/datachannel/basic-tcp.html crashes on all platforms but does not have a valid crash log on Mac platforms.

History:
https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=webrtc%2Fdatachannel%2Fbasic-tcp.html

Example results:
https://build.webkit.org/results/Apple%20Sierra%20Release%20WK2%20(Tests)/r223296%20(5007)/results.html

error:
No crash log found for com.apple.WebKit.Networking.Development:423.

While not extremely flaky, this does cause the trees to go red occasionally.

[Radar WebKit Bug Importer]

<rdar://problem/34985374>

[Jonathan Bedard]

Here's the build: <https://build.webkit.org/builders/Apple%20Sierra%20Release%20WK2%20%28Tests%29/builds/5007>

Something strange if definitely going on.  I would expect us to pick up a crash-log from the networking process.  It's almost as if the networking process is being killed rather than crashing.

[Alexey Proskuryakov]

This is somewhat reproducible, but hard to catch in a debugger:

run-webkit-tests webrtc/datachannel/basic-tcp.html --repeat 1000 --no-show --no-build --no-timeout -f

I may have caught this in debugger once, the Networking process died because of a SIGPIPE. The symptom matches, although this could be a user error.

[Alexey Proskuryakov]

Definitely SIGPIPE, sent from the Networking process itself. It looks like libwebrtc tries to handle this signal in a couple places, but that's not quite working.

I couldn't get a good stack trace for where the signal is sent from, my probe prints unsymbolicated traces for some reason.

sudo dtrace -n 'proc:::signal-send /pid/ { printf("%d %s -%d %d",pid,execname,args[2],args[1]->pr_pid); ustack(); }'

[Alexey Proskuryakov]

A reproducible crash in a test with "basic" in its name seems particularly worth looking into.

[youenn fablet]

Created attachment 337534 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 337534 [details]
Patch

Clearing flags on attachment: 337534

Committed r230492: <https://trac.webkit.org/changeset/230492>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[youenn fablet]

Reopening to attach new patch.

[youenn fablet]

Created attachment 354042 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 354042 [details]
Patch

Clearing flags on attachment: 354042

Committed r237970: <https://trac.webkit.org/changeset/237970>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.