1769459 - thread locks up (100% CPU) on opening message

Status: RESOLVED WORKSFORME

(Thunderbird :: Untriaged, defect)

Description

[Niklas Beisert]

Attachment: msg-lockup.eml

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0

Steps to reproduce:

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0
Build ID: 20220401203107
OS: Linux 5.10.0-14-amd64 #1 SMP Debian 5.10.113-1 (2022-04-29)

Open some particular message (attached, typically sent by "Outlook on the Web for Exchange Server 2016", with large base64 attachment and pkcs7-signature) on an IMAP account. This triggers symptoms similar to bug 1753282 and bug 1744423.

Issue is realiably caused by opening a specific message as the first message within a TB session. It is also triggered at TB launch when the message has remained open in a tab from last session. Issue can also be triggered (sometimes, but not always) when a message of this kind is opened during normal operations.

What does not change behaviour:

• troubleshoot mode
• view options (plain, simple, original HTML), display attachments inline
• MOZ_DISABLE_RDD_SANDBOX=1

What avoids the issue (any of the below):

• opening the .eml message file from the command line
• opening the message from within local folders (rather than IMAP)
• opening the message in an offline folder (message synchronisation)
• no / small / text encoded attachment
• no pkcs7-signature

Notes:

• strace output similar to attachment in bug 1753282 (but also in normal operation)
• nothing significant in error console and console in developer toolbox
• issue has been around for a while, likely before TB 91

Actual results:

Thunderbird starts using one CPU core at around 100% (+ fan activity, + noticable power consumption on laptop). Otherwise no noticable impairment of the running TB instance. However, once the TB user interface is closed, the thread continues, TB keeps running in the background with 100% usage of one CPU core without end. Trying to launch a new instance of TB results in a popup: "Thunderbird is already running, but is not responding. ...". The unresponsive TB can be stopped by "killall thunderbird" (symptoms are similar to bug 1753282 and bug 1744423, but cause is more concrete than running TB for some time).

Expected results:

Thread should not lock up and consume 100% CPU. TB should quit properly and relaunch when requested.

Comment 1

[Niklas Beisert]

Attachment: msg-small.eml

this message does not trigger issue

Comment 2

[Niklas Beisert]

Attachment: msg-unsigned.eml

message does not trigger issue

Comment 3

[Wayne Mery (:wsmwk)]

Does this reproduce with version 102 from https://www.thunderbird.net/ ?

Comment 4

[Niklas Beisert]

In short: Looks good in official thunderbird 102.x! Many thanks!
More detail: I tried with several official versions 91.0 through 91.12 with a copy of my profile and I could reproduce the problem (not always, but in all tried versions it eventually triggered and the thunderbird process never exited without force). I also tried with official 102.0 and 102.1 with a copy of my profile (automatically upgraded) and I never saw the problem, thunderbird process always exited as it should. I'm waiting for a debian bullseye release version of the 102.x branch, but given the above, I'd expect the issue to be resolved there.