Just a quick post to reply to the comments I’ve had on some previous posts.

On Missing entropy on my server box, I received lots of comments on how to feed random other stuff into the entropy pool or make it bigger or other hacks, but Alexander Reelsen pointed me to the real cause — a kernel bug in older 2.4 kernels which causes the entropy pool to deadlock on SMP systems, and never get refilled. There is a patch from RedHat which backports the fix from 2.6, and is included in recent 2.4 kernels.

On the topic of kernels, now I’ve upgraded from 2.4.29-rc1 to 2.4.32-rc1 I get lots of errors like hw tcp v4 csum failed in my syslog. I’m using the e100 driver which as far as I can see hasn’t changed between versions, but there have been some changes to TCP checksumming code which I havn’t quite been able to grok. Google finds mailing list posts with other people asking what the cause is, but nobody answering. Anyone know what’s going on there?

On Windows accessibility, many people seem to not listened to the first couple of minutes of the tasteless song I linked to, and hence taken my comment completely seriously. Thanks to everyone who told me about sticky keys etc in comments, but I did already know about the existence of Windows accessibility support (warning: mjg59 in furious anger mode). 😀

On the topic of blog comments, how do I cut down on the comment spam I have to moderate without requiring people to go through a completely unaccessible captcha image thing, or the annoyance of registering and acknowledging an e-mail? Would prohibiting comments and URIs containing words like ‘mortgage’, ‘casino’ and ‘ringtone’ ever cause false positives?

While pondering the delightfully tasteless Snippets song from Amateur Transplants (authors of the London Underground song), I realised that until the requirement to press Ctrl+Alt+Delete is removed, Windows will always remain unaccessible to certain users.

One of my servers has apache2 and mod_perl on it to play with some crazy stuff like dyamically looking up virtual hosts in postgres, but every time I restart apache2 for whatever reason, it blocks reading /dev/random and never starts up. A little research shows this is mod_perl trying to initialise its UUID generator with some quality system entropy (why? is it strictly necessary? are the UUIDs that important?). The problem is, it never succeeds because this machine never has any entropy:
$ cat /proc/sys/kernel/random/poolsize
512
$ cat /proc/sys/kernel/random/entropy_avail
0
It’s a headless box with no serial, mouse, keyboard or USB devices, so the only IO it sees is disk and network. How do I find out what’s eating all the entropy, or does it in fact just never have any due to nothing feeding it in the kernel? What can I do to identify and address the actual source of the problem (ie not just making /dev/random a link to /dev/urandom or patching mod_perl to just read /dev/urandom or use /proc/sys/kernel/random/uuid to make its UUIDs)?

OK, I admit this is exceedingly old but still highly amusing (if somewhat nauseating). If you thought my take on Britney Spears yesterday was bad, a friend who’s just started at the pan-global accounting firm KPMG has just mailed me a copy of the (long since completely disowned) company song, “KPMG (As Strong As Can Be)”. Set to incredibly cheesy synth music, the chorus goes:

KPMG – We’re strong as can be,
A team of power and energy,
We go for the gold, together we hold
Onto our vision of global strategy.

Wired has the details from 2001 and a copy of the offending song on the 2nd page. I won’t link to KPMG in case their lawyers e-mail me…

I apologise in advance. It’s all Rob Taylor‘s fault, while we were looking at garbage collection (or not) of Python D-BUS service objects. In my defence, I was thinking of the Travis cover rather than Britney’s version.

Oh baby, baby
How was I supposed to know
This memory’s from the heap
Oh baby, baby
I shouldn’t have let it go
And now its out of scope, yeah
Show me where I should have called free
Tell me baby ’cause I need to know now, oh because

My memory leak is killing me
I must confess, I still believe
When all my objects are hard to find
Give me a count
Ref me baby one more time

I’ve sometimes pondered what would happen to me if I was out on my own, was in some kind of an accident and the ambulance staff didn’t know who to contact, so I’ve always kept obvious things like “Home” and “Mum” in my mobile’s phone book even though I know their numbers. I’ve just heard about the “In Case of Emergency” (ICE) campaign, where you prefix a number in your phone book with ICE, so the ambulance staff can find it quickly and know who to contact to seek consent for emergency treatment. According to Vodafone, “75% of people carry no details of who they would like telephoned following a serious accident”. More details from East Anglian Ambulance Service and Vodafone.

I noticed this error today:
Jul 29 00:54:50 light imaplogin: malloc: Input/output error

Note helpful lack of pid, so I had to strace all my imapds to track it down and then grep through source code for calls to perror (random guesswork). And it’s caused by… wait for it… famd not running (see #294656). Of course!

No, really. WTF?!?! I’m switching to dovecot. Utter utter crack.

Update: Corrected the bug number. #308313 is the other problem I’ve been debugging today, the combination of the two leading me to believe my machine was rooted or had f🤬d hardware. I utterly hate both courier *and* proftpd, and will be switching to dovecot and vsftpd as soon as possible.

In unstable, aalib1 has just been renamed to libaa1, in line with normal shared library naming policies, giving rise to the following:
$ apt-cache search libaa
...
libaa1-dev - ascii art library, development kit
libaal-dev - Reiser4's application abstraction library
...
Which is more useful? Which has more users? Which is on more crack? 😀

Where can you find dbus? Only in Finland!
Come to Debconf we’ve got dbus!

With apologies to Weebls Stuff.

TAKE YOUR 802.11X AND SHOVE IT UP YOUR A🤬HOLE