Comment 59 for bug 571247

I'm still affected by this. My test case is Ubuntu 12.04.2, 32-bit, fully up to date as of this morning. As I write this my version of firefox is 22.0+build2-0ubuntu.12.04.1 and my version of acroread is 9.5.5-1precise1.

When I start Firefox and open a PDF in a tab, Firefox spawns a plugin-container for nppdf.so, and that in turn spawns an acroread. If I close the PDF tab and wait a few seconds, acroread exits but is not immediately reaped, so a defunct (zombie) acroread remains.

If I try to open another PDF in a tab while the zombie is present, all I get is a black screen.

After a longer time the plugin-container exits, taking the acroread zombie with it. After that, I can open a PDF normally again, since a new plugin-container and acroread are created.

Disabling the out-of-process plugins feature in Firefox globally (dom.ipc.plugins.enabled=false) seems to function as a workaround, but blacklisting only the nppdf plugin (dom.ipc.plugins.enabled.nppdf.so=false) still sometimes gives me a black screen, even though a plugin-container isn't created.