1172157 - Profiler returning malformed JSON

Status: RESOLVED WORKSFORME

(DevTools :: Performance Tools (Profiler/Timeline), defect)

Description

[Victor Porof [:vporof][:vp]]

error occurred while processing 'getProfile: SyntaxError: JSON.parse: unexpected end of data at line 1 column 1 of the JSON data
Stack: ProfilerActor.prototype.onGetProfile@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/actors/profiler.js:182:19
DSC_onPacket@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/main.js:1469:15
LocalDebuggerTransport.prototype.send/<@resource://gre/modules/devtools/dbg-client.jsm -> resource://gre/modules/devtools/transport/transport.js:569:11
makeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/DevToolsUtils.js:82:14
makeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/DevToolsUtils.js:82:14
Line: 182, column: 18

onPacket threw an exception: Error: Server did not specify an actor, dropping packet: {"error":"unknownError","message":"error occurred while processing 'getProfile: SyntaxError: JSON.parse: unexpected end of data at line 1 column 1 of the JSON data\nStack: ProfilerActor.prototype.onGetProfile@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/actors/profiler.js:182:19\nDSC_onPacket@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/main.js:1469:15\nLocalDebuggerTransport.prototype.send/<@resource://gre/modules/devtools/dbg-client.jsm -> resource://gre/modules/devtools/transport/transport.js:569:11\nmakeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/DevToolsUtils.js:82:14\nmakeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/DevToolsUtils.js:82:14\nLine: 182, column: 18"}
Stack: DebuggerClient.prototype.onPacket@resource://gre/modules/devtools/dbg-client.jsm:968:1
LocalDebuggerTransport.prototype.send/<@resource://gre/modules/devtools/dbg-client.jsm -> resource://gre/modules/devtools/transport/transport.js:569:11
makeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/DevToolsUtils.js:82:14
makeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/DevToolsUtils.js:82:14
Line: 968, column: 0

Comment 1

[Victor Porof [:vporof][:vp]]

Happened while profiling this page.

Comment 2

[Jordan Santell [:jsantell] [@jsantell]]

Was it a fresh-ish instance or one running for a few hours/days?

Saw an exception in C++ with similar but assumed it was me.

Comment 3

[Victor Porof [:vporof][:vp]]

(In reply to Jordan Santell [:jsantell] [@jsantell] from comment #2)
> Was it a fresh-ish instance or one running for a few hours/days?
> 
> Saw an exception in C++ with similar but assumed it was me.

A few hours old firefox.

Comment 4

[Shu-yu Guo [:shu]]

Attachment: Save malformed profile JSON to file to help debug.

Saves malformed JSON to ~/bad-profile.json. We'll back this out after catching
where the parse error is exactly.

Comment 5

[Shu-yu Guo [:shu]]

I wonder if it's bug 1167895.

Comment 6

[Benoit Girard (:BenWa)]

Comment on attachment 8616281 [details] [diff] [review]
Save malformed profile JSON to file to help debug.

Review of attachment 8616281 [details] [diff] [review]:
-----------------------------------------------------------------

::: tools/profiler/TableTicker.cpp
@@ +230,5 @@
> +      if (homePath) {
> +        nsCString path;
> +        path.Append(homePath);
> +        path.Append('/');
> +        path.Append("bad-profile.json");

I don't like the idea of writing files on people' disk. The nightly population is much more than just mozilla employees. This is used by devtools now so a lot of people can hit this code. This would be a bit better if we wrote this out in the profile directory.

How about just sending it to stdout? It's not that uncommon so we should watch stdout.

Comment 7

[Shu-yu Guo [:shu]]

Attachment: Save malformed profile JSON to file to help debug.

Write out to a temp dir instead.

Comment 8

[Benoit Girard (:BenWa)]

Comment on attachment 8616832 [details] [diff] [review]
Save malformed profile JSON to file to help debug.

Review of attachment 8616832 [details] [diff] [review]:
-----------------------------------------------------------------

Looks good. Might want to add a notification to stdout.

Comment 9

[Jordan Santell [:jsantell] [@jsantell]]

Can we have a pref that specifies a path to dump this too? Then we can opt in

Comment 10

[Shu-yu Guo [:shu]]

(In reply to Jordan Santell [:jsantell] [@jsantell] from comment #9)
> Can we have a pref that specifies a path to dump this too? Then we can opt in

I was planning on backing this out when we actually catch the error. Too much work for a temporary thing.

Comment 11

[Shu-yu Guo [:shu]]

(In reply to Benoit Girard (:BenWa) from comment #8)
> Comment on attachment 8616832 [details] [diff] [review]
> Save malformed profile JSON to file to help debug.
> 
> Review of attachment 8616832 [details] [diff] [review]:
> -----------------------------------------------------------------
> 
> Looks good. Might want to add a notification to stdout.

Sure, will do.

Comment 12

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/a047d84164b1

Comment 13

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/a047d84164b1

Comment 14

[Shu-yu Guo [:shu]]

I asked Jordan and Victor in person about seeing any dumped malformed profiles, and they didn't see any.

Benoit and Markus, have you seen any?

Comment 15

[Markus Stange [:mstange]]

I haven't seen this since this landed, seems fixed to me.

Comment 16

[Benoit Girard (:BenWa)]

Yes I haven't seen it either. I've checked a few times in the past and again today.

Looks like this no longer fails for some reason.

Comment 17

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/004e8bb3f339

Comment 18

[Shu-yu Guo [:shu]]

Nobody has seen any bad profiles for a while. Backed out temporary dumping patch in https://hg.mozilla.org/integration/mozilla-inbound/rev/004e8bb3f339

Comment 19

[Robert G. Siebeck]

I can reproduce this issue with Firefox 40.0.2 on 64bit Linux by running a runtime analysis on this Bugzilla page (open this page, start runtime analysis, refresh page, end runtime analysis, see exception in .xsession-errors). Here's the log output:

onPacket threw an exception: Error: Server did not specify an actor, dropping packet: {"error":"unknownError","message":"error occurred while processing 'getProfile: SyntaxError: JSON.parse: unexpected end of data at line 1 column 1 of the JSON data\nStack: ProfilerActor.prototype.onGetProfile@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/actors/profiler.js:182:19\nDSC_onPacket@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/main.js:1456:15\nLocalDebuggerTransport.prototype.send/<@resource://gre/modules/devtools/dbg-client.jsm -> resource://gre/modules/devtools/transport/transport.js:561:11\nmakeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/DevToolsUtils.js:82:14\nmakeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/DevToolsUtils.js:82:14\nLine: 182, column: 18"}
Stack: DebuggerClient.prototype.onPacket@resource://gre/modules/devtools/dbg-client.jsm:944:1
LocalDebuggerTransport.prototype.send/<@resource://gre/modules/devtools/dbg-client.jsm -> resource://gre/modules/devtools/transport/transport.js:561:11
makeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/DevToolsUtils.js:82:14
makeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/DevToolsUtils.js:82:14
Line: 944, column: 0

Comment 20

[Robert G. Siebeck]

Seems like this issue is related to an Add-In (uBlock Origin). Here's the related issue: https://github.com/gorhill/uBlock/issues/627

Comment 21

[Markus Stange [:mstange]]

Looks like the fix for this (bug 1167895) only landed in Firefox 41, not in 40. So unfortunately it looks like this is going to stay unfixed until Firefox 41 will be released.

Comment 22

[Firefox Bug Husbandry Bot]

Removing leave-open keyword from resolved bugs, per :sylvestre.