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Re: GLibc hang on in gethostbyname


Hi all,

I experienced a race-condition between accept() and listen(), ended in
a dead-lock I think. No more connections were accepted.

Are you sure that not your server hangs?

As I wanted to debug and added some debugging messages, it just
worked. So I think there is a race-condition.

Sorry, for the delayed response, I just had to formulate the issue.

Yeah, there is something wrong. I am busy but you hear from me later.

regards,
Joël


On Thu, Sep 5, 2019 at 9:47 PM Carlos O'Donell <carlos@redhat.com> wrote:
>
> On 9/5/19 7:21 AM, David Ignjić wrote:
> > Probably, i don't think its hw problem this happen in our both hosting
> > centres only what is in my mind we have running machines on vm with  qemu.
>
> The lookup function is fairly straight forward, it locks upon entry, and
> then unlocks on exit. You don't appear to have duplicate stack frames
> in the backtrace (no recussion), and you also don't appear to have any
> signal handlers in the backtrace (AS-safety issues).
>
> Speaking of serial execution orderings there is no way this results in
> deadlock unless:
>
> * The compiler did something unexpected.
>
> * The memory for the lock was corrupted.
>
> Is there a point at which this didn't happen? Are you able bisect if the
> version of glibc makes a difference?
>
> --
> Cheers,
> Carlos.


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