978690 - Firefox hangs often when communicating with local process

Status: RESOLVED INVALID

(Core :: Networking, defect)

Description

[Georg Koppen]

Attachment: torbutton_send_ctrl_cmd -- JavaScript function that triggers the hang

When starting TorBrowser, which is based on Firefox (currently ESR24), it is communicating with a local tor process (sending commands and receiving responses) which is implemented in extensions. We often (although not always) encounter hangs in the function torbutton_send_ctrl_cmd() (attached). Upon further investigation there seems to be an underlying problem when writing the bytes (see the attached stacktrace).

Comment 1

[Georg Koppen]

Attachment: stacktrace

Comment 2

[Georg Koppen]

If it helps I can generate stacktraces with --disable-optimize. If there are other things I can do to debug that further or help you debugging this let me know.

Comment 3

[Georg Koppen]

Okay, adding some output gathered with NSPR logging:

-1220368640[b722a300]: creating nsSocketTransport @9d128e00
-1220368640[b722a300]: nsSocketTransport::Init [this=9d128e00 host=127.0.0.1:9151 proxy=:0]
-1220368640[b722a300]: nsSocketTransport::PostEvent [this=9d128e00 type=3 status=0 param=0]
-1220368640[b722a300]: STS dispatch [aa76cde0]
-1220368640[b722a300]: nsSocketTransport::OpenInputStream [this=9d128e00 flags=3]
-1220368640[b722a300]: STS dispatch [aa46c2e8]
-1220368640[b722a300]: nsSocketTransport::PostEvent [this=9d128e00 type=0 status=0 param=0]
-1220368640[b722a300]: STS dispatch [aa76ce00]
-1220368640[b722a300]: nsSocketTransport::OpenOutputStream [this=9d128e00 flags=3]
-1220368640[b722a300]: STS dispatch [aa46c338]
-1220368640[b722a300]: nsSocketTransport::PostEvent [this=9d128e00 type=0 status=0 param=0]
-1220368640[b722a300]: STS dispatch [aa76ce40]
-1220368640[b722a300]: OOO WriteSegments [this=a18ed2ac count=47]
-1220368640[b722a300]: OOO appended new segment
-1220368640[b722a300]: OOO rolling back write cursor 0 bytes
-1220368640[b722a300]: OOO SegmentLen is 1
-1220368640[b722a300]: OOO ReadCount is 1
-1220368640[b722a300]: OOO advancing write cursor by 1
-1220368640[b722a300]: OOO pipe output: waiting for space
-1690313920[aa456940]: STS dispatch [aa49a3a0]
-1673528512[aa456640]: STS dispatch [aa48fac0]
-1681921216[aa4567c0]: STS dispatch [aa496ec0]

I guess this is some networking issue that happens in rare conditions although it is pretty reliably triggerable if I load a bunch of bookmarks, close the tabs while they are still loading and call torbutton_send_ctrl_cmd() in my debug build. Ideas for further investigation still welcome. :)

Comment 4

[Georg Koppen]

This is not a Mozilla issue but due to our use of blocking sockets. Sorry for the noise.