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Re: call ngx_localtime may cause deadlock?

March 04, 2010 02:58PM
On Thu, Mar 04, 2010 at 07:49:57PM +0300, Maxim Dounin wrote:

> Hello!
>
> On Thu, Mar 04, 2010 at 10:20:29AM -0500, georgexsh wrote:
>
> > Igor Sysoev Wrote:
> > -------------------------------------------------------
> >
> > > Here is third-party module which probably uses
> > > threads:
> > >
> > > #11 0x08088c9f in ngx_foo_time_str (r=0x9dcdc28,
> > > time_str=0xbfe18450, t=-4) at
> > > ./ngx_foo_module//uti.c:111
> > > #12 0x08087d1a in ngx_http_foo_record
> > > (r=0x9dcdc28, request_arg=0x9dcddb0) at
> > > ./ngx_foo_module//foo.c:124
> > > #13 0x0808788c in ngx_http_foo_handler
> > > (r=0x9dcdc28) at
> > > ./ngx_foo_module//ngx_http_foo_module.c:74
> > >
> >
> >
> > No, ngx_foo_module/* is my module which does't use threads ethier.
> >
> > ref:
> > http://blogs.inxsasia.com/hiran/2009/07/stupid-futex-and-glibc.html
> > http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=301511
>
> Ok, second link suggest that recent glibc uses futex even when
> there are no threads in application.
>
> This isn't really relevant though as underlying problem is in
> nginx and should be fixed anyway. Only async-signal-safe
> functions may be used in signal handlers, anything else leads to
> undefined behaviour.

Strickly speaking the generic signal handler calls localtime/_r() too:
ngx_time_update(0, 0);

And if timer_resolution bug can be fixed easy, nevertheless, I do not
know how to log local time in singal handler without localtime().


--
Igor Sysoev
http://sysoev.ru/en/

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Subject Author Posted

call ngx_localtime may cause deadlock?

georgexsh March 04, 2010 05:09AM

Re: call ngx_localtime may cause deadlock?

Maxim Dounin March 04, 2010 07:18AM

Re: call ngx_localtime may cause deadlock?

Igor Sysoev March 04, 2010 07:26AM

Re: call ngx_localtime may cause deadlock?

georgexsh March 04, 2010 10:20AM

Re: call ngx_localtime may cause deadlock?

Maxim Dounin March 04, 2010 11:54AM

Re: call ngx_localtime may cause deadlock?

Igor Sysoev March 04, 2010 02:58PM

Re: call ngx_localtime may cause deadlock?

Maxim Dounin March 04, 2010 08:02PM



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