Error occured at /json/categories at chrome://tracing/tracing.js:5194:31

[natduca]

From pasko@chromium.org on February 13, 2014 15:44:42

I get the message as in the subject line when I click on "Record" in about:tracing.

Google Chrome 34.0.1825.4 (Official Build 249291) dev
OS Linux
Blink 537.36 (@166573)
JavaScript V8 3.24.32
Flash 12.0.0.44
User Agent Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1825.4 Safari/537.36
Command Line /usr/bin/google-chrome-unstable --user-data-dir=/home/pasko/.config/google-chrome-unstable --flag-switches-begin --ignore-gpu-blacklist --flag-switches-end

Original issue: http://code.google.com/p/trace-viewer/issues/detail?id=533

[natduca]

From tonyg@chromium.org on March 12, 2014 08:35:31

I think this issue belongs here: https://code.google.com/p/trace-viewer/issues/list

Status: ExternalDependency
Cc: nd...@chromium.org
Labels: -Performance-Tool

[natduca]

From nd...@chromium.org on March 12, 2014 13:08:26

Hmm not really enough to go on here about what's going wrong. @pasko, if you open the inspector, do you get more data on the console?

Status: Unconfirmed
Cc: haraken@chromium.org wangxianzhu@chromium.org

[natduca]

From Sar...@gmail.com on May 07, 2014 02:09:57

Getting a similar error.

I click the record button, nothing happens, I click it again, I get a similar error.

Checking in the console it is making a request to

chrome://tracing/json/categories

Going to that url. I am getting.

##ERROR##

If I go to that URL before clicking the button, I am getting.

["ETW Trace Event","FileSystem","IndexedDB","RLZ","ValueStoreFrontend::Backend","WebCore","base","benchmark","blink_rendering","blink_rendering,comp-scroll","browser","cc","cc,benchmark","cc,devtools","content","disabled-by-default-blink.debug.layout","disabled-by-default-blink.graphics_context_annotations","disabled-by-default-cb_command","disabled-by-default-cc.debug","disabled-by-default-cc.debug,disabled-by-default-cc.debug.quads","disabled-by-default-cc.debug.quads","disabled-by-default-cc.debug.scheduler","disabled-by-default-gpu.debug","disabled-by-default-gpu.device","disabled-by-default-gpu.service","disabled-by-default-style.debug","disabled-by-default-system_stats","disabled-by-default-toplevel.flow","frame_host","gpu","input","leveldb","loader","mirror","net","renderer","renderer_host","shutdown","skia","startup","sync","sync_lock_contention","test_gpu","trace_event_overhead","ui","v8","views","webkit","webrtc"]

Once the error occurs the browser is unusable.

Version 34.0.1847.131 m

[natduca]

From Sar...@gmail.com on May 07, 2014 03:22:37

By adding breakpoints to see what happens the record dialog showed up where it should have and ever since, it has worked again, so some sort of cache error maybe?

[natduca]

From nd...@chromium.org on July 25, 2014 22:16:02

Do we have a stable repro of this on ToT? If not, Ima wontfix this.

[natduca]

From igrigorik@chromium.org on August 26, 2014 09:12:26

Seeing same issue here on OSX, Version 37.0.2062.94.

No errors in the inspector, but can't record anything either.

Attachment: Screen Shot 2014-08-26 at 9.10.58 AM.png

[natduca]

From nd...@chromium.org on August 28, 2014 06:22:44

Folks experiencing this: what happens when you start with --user-data-dir=/something/fresh?

[sunnyps]

I can reproduce this issue with Version 39.0.2171.71 (64-bit) on OS X 10.9. I could also reproduce with the Dev channel. I tried deleting my chrome profile but the issue still persists.

[ariccio]

I may have found something useful. On hitting r to start a trace, I saw this in sawbuck:

VERBOSE 49924   48704   13:35:53-569        0   Upload finished with net error 0 and HTTP response code 200
VERBOSE 49924   48704   13:35:54-342        0   OnResponseStarted: chrome://tracing/json/end_recording
VERBOSE 49924   48704   13:35:54-343        0   OnReadCompleted: "chrome://tracing/json/end_recording" bytes_read = 9
VERBOSE 49924   48704   13:35:54-343        0   OnReadCompleted: "chrome://tracing/json/end_recording" bytes_read = 0
VERBOSE 49924   48704   13:35:54-343        0   ResponseCompleted: chrome://tracing/json/end_recording
VERBOSE 49924   48704   13:35:54-345        0   OnResponseStarted: chrome://tracing/json/categories
VERBOSE 49924   48704   13:35:54-346        0   OnReadCompleted: "chrome://tracing/json/categories" bytes_read = 9
VERBOSE 49924   48704   13:35:54-346        0   OnReadCompleted: "chrome://tracing/json/categories" bytes_read = 0
VERBOSE 49924   48704   13:35:54-346        0   ResponseCompleted: chrome://tracing/json/categories

I think that means a FAILED path (via 230) through OnBeginJSONRequest ( notice that "##ERROR##" is exactly 9 characters/bytes long! ), followed by a second FAILED path (via 211) through OnBeginJSONRequest.

I think that the offending function/class/object/whatever is XhrBasedTracingControllerClient.prototype.

I set a few billion breakpoints, and stepped through in the debugger. Here are some screenshots of the process. They're (hopefully) in order:

[ariccio]

A word of warning for those who lack experience with the JS debugger in Chrome:

I was quite frustrated when my breakpoints were mysteriously failing, apparently because I'd clicked the Pretty print button.

.....I swear to god, after setting a million breakpoints in the formatted file, I was furious.

( spec. thanks: @randomascii )