Re: dd hangs with SIGINT

[Guillaume Chazarain]

Paul Eggert wrote:

> Guillaume Chazarain <address@hidden> writes:
>  
>
> > With recent linux distributions (using NPTL), dd can hang waiting on
> > a futex when being killed.
> >    
>
> I'm not quite sure how to parse that, but it sounds like a problem
> with some part of the system other than "dd", not with "dd" itself.
>  
Maybe, I first thought about posting it to LKML.

> When "dd" gets a signal, it closes the input and output files, prints
> some statistics, and exits.  If it gets a second signal it exits
> immediately.  I don't offhand see why this could cause a hang that was
> dd's fault.
>  
I thought calling fprintf in a signal handler was risky, but it's not, 
so yes it should
not be dd's fault. Sorry for the noise.

> It sounds like you may need to investigate this on your own host.
>  
Actually it happens on many hosts : Fedora Core[1-3] and it disappear 
with LD_ASSUME_KERNEL=2.4.
But if only me can see the "dd frozen"_//_/__/ loop with a recent 
kernel, my hopes are low :-(

> You don't mention which version of "dd" you're having the problem
> with.  "dd --version" should tell you.
>  
Both 5.2.1 and 5.3.0.

Thank you.

--
Guillaume