Bug#842796: libc recently more aggressive about pthread locks in stable ?

[Aurelien Jarno]

On 2016-11-05 19:13, Ian Jackson wrote:
> I have just been debugging a ghostscript segfault on jessie amd64.
> 
> Looking at the code, I think that gs in jessie is plainly violating
> the rules about the use of pthread locks.  On my partner's machine,
> this makes it segfault on termination (with some input files, at
> least).  On my machine it works just fine.  The code in sid is better.
> 
> I recently encountered what seems to be a similar bug in ogg123 in
> stable.  #842796.
> 
> Has something changed in jessie's libc recently ?  I find it difficult
> to imagine that these bugs would have been missed earlier during the
> life of jessie.

I think you just got a new machine with a CPU supporting the TSX
instructions, which are more picky about following the pthreads
semantics.

Unfortunately given Intel fuck-up on TSX implementation in Haswell and
some Broadwell CPUs, they had to disable TSX instructions though firmware
updates, which in turns means we haven't got all packages in Jessie
tested by a wide set of people.

Aurelien

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien at aurel32.net                 http://www.aurel32.net