David Bremner <david@tethera.net> writes:

> Brian May <bam@debian.org> writes:
>> strace shows notmuch looping in select.
>>
>> select(10, [9], [], NULL, {1, 0})       = 0 (Timeout)
>> select(10, [9], [], NULL, {1, 0})       = 0 (Timeout)
>> select(10, [9], [], NULL, {1, 0})       = 0 (Timeout)
>> select(10, [9], [], NULL, {1, 0})       = 0 (Timeout)
>> etc
>>
>
> a backtrace would be helpful.
>
> d

Nevermind, I managed to download the list archive for debian-devel and
replicate the bug.

The bug seems to be related to smime signature verification. After
adding the attached mail message (and running notmuch-new), to replicate
the hang it suffices to run

% notmuch show --decrypt id:20161116T143809.GA.21721.stse@fsing.rootsland.net  

As far as workarounds, turning off decryption / signature verification
should allow you to at least view the thread.