387180 - form field autocomplete hangs app and window manager

Status: RESOLVED WORKSFORME

(Toolkit :: Form Manager, defect)

Description

[Myk Melez [:myk] [@mykmelez]]

On yesterday's and today's nightly builds, when I type something into a form field on a web page, and the form autocomplete drop-down menu appears, the application and the window manager hangs after I have typed a few characters.

The number of characters (and which ones I've typed) isn't consistent, but the hang is.  It happens almost every time as long as the text I am typing has some autocomplete entries, and I can reproduce on both bugzilla.mozilla.org (in the Summary field on the Enter Bug page, the "Reassign bug to" field on a Show Bug page, and the Words field on the Find a Specific Bug page), and in the search field on google.com.

In fact, I had to type the summary of this bug into the Description field and then copy-paste it into the Summary field to avoid triggering the bug.  On the other hang, I was able to quickly type "gavin" into the CC: field and then tab out of the field without triggering the bug, even though that string has an autocomplete entry in my profile.

Although both the application and the window manager hangs, and I can't close windows or move between windows or desktops using the mouse or keyboard shortcuts, other applications remain responsive.  For example, the Ubuntu applet that appears when an software update is available appeared during one hang, and both top and "watch --interval 0.5 iostat" in a terminal window continue to update normally.

Once I kill Firefox (via "killall firefox-bin" from another virtual console), the window manager becomes responsive again.  While it's hung, top and iostat show no unusual CPU or disk activity.  The hang doesn't appear to get triggered by chrome autocomplete (f.e. in the location or search bars).

Comment 1

[Myk Melez [:myk] [@mykmelez]]

Note: when this happens, strace shows the process stuck on a futex call.

Comment 2

[Karl Tomlinson (:karlt)]

I can't reproduce here, but, if the Xserver is configured with

Section "ServerFlags"

        ...

        Option      "AllowDeactivateGrabs" "on"


then Ctrl+Alt+Keypad-Divide may free up the keyboard and mouse clicks for other apps.

Comment 3

[Myk Melez [:myk] [@mykmelez]]

I can't reproduce this anymore.  Perhaps a change in a recent nightly has fixed it.  In any case, resolving worksforme.  I'll reopen if the problem returns.