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Re: nscd frequent assertion failure...
- From: Petr Baudis <pasky at ucw dot cz>
- To: Daniel J Blueman <daniel dot blueman at gmail dot com>
- Cc: Ubuntu Core developers <ubuntu-devel-discuss at lists dot ubuntu dot com>,libc-help at sourceware dot org, drepper at redhat dot com,Pierre Habouzit <madcoder at debian dot org>
- Date: Sat, 22 Nov 2008 20:08:50 +0100
- Subject: Re: nscd frequent assertion failure...
- References: <6278d2220811220454n197420eap37c9c00f86cb6fa0@mail.gmail.com>
Hi,
On Sat, Nov 22, 2008 at 12:54:18PM +0000, Daniel J Blueman wrote:
> glibc 2.8's name-service cache daemon (nscd) is seeing frequent
> assertion failure [1], at least in Ubuntu 8.10, due to internal
> consistency checks failing (memory object misalignment). Right now in
> the 8.10 Intrepid cycle, this is 100% of the crashes I've had over the
> last week's workflow.
>
> Since nscd is not installed by default on many distros, this isn't
> getting the minimum exposure and attention to get addressed, sadly.
> I've been unable to find any fixed/unfixed bug reports, and I've
> tracked this with valgrind [2].
>
> Is anyone else seeing this, and has any suggestions about the best way forward?
I think the best solution is to just upgrade to glibc-2.9's nscd code,
which works much better - we will be doing that within a maintenance
update for OpenSUSE 11.0:
https://bugzilla.novell.com/show_bug.cgi?id=387202
Even in glibc-2.9, there is still an open race between gc() and adding
to the cache, as described in:
http://sourceware.org/bugzilla/show_bug.cgi?id=5381
This still leads to occassional crashes, but much less frequent than
in glibc-2.8 and should be fixed soon.
SUSE does enable nscd by default - I have been unable to look into
these issues before, but we are very careful to have rock-solid stable
nscd in our upcoming SLES11. In the longer term, we are considering to
switch to unscd for its more robust design.
--
Petr "Pasky" Baudis
People who take cold baths never have rheumatism, but they have
cold baths.