From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4B73C214.3010107@domain.hid> Date: Thu, 11 Feb 2010 09:38:44 +0100 From: Jan Kiszka MIME-Version: 1.0 References: <4B72A7E2.5020001@domain.hid> <4B72A9DA.1090104@domain.hid> <4B730A04.9040908@domain.hid> <4B731608.6010803@domain.hid> <4B73180C.6070301@domain.hid> <4B73207C.6020400@domain.hid> <4B73218A.9080306@domain.hid> <4B7323D5.1040804@domain.hid> <4B732487.50103@domain.hid> <4B732679.4030306@domain.hid> <4B73278F.9050603@domain.hid> In-Reply-To: <4B73278F.9050603@domain.hid> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-core] [Xenomai-git] Jan Kiszka : Make xnarch_init_timeconv an uninlined weak function List-Id: Xenomai life and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gilles Chanteperdrix Cc: Xenomai core Gilles Chanteperdrix wrote: > Jan Kiszka wrote: >> Gilles Chanteperdrix wrote: >>> Jan Kiszka wrote: >>>> Gilles Chanteperdrix wrote: >>>>> Jan Kiszka wrote: >>>>>> Gilles Chanteperdrix wrote: >>>>>>> Jan Kiszka wrote: >>>>>>>> Gilles Chanteperdrix wrote: >>>>>>>>> Jan Kiszka wrote: >>>>>>>>>> Gilles Chanteperdrix wrote: >>>>>>>>>>> GIT version control wrote: >>>>>>>>>>>> Module: xenomai-jki >>>>>>>>>>>> Branch: for-upstream >>>>>>>>>>>> Commit: 6b40653e9c3c4a2433bb4e91344fc378eb860f75 >>>>>>>>>>>> URL: http://git.xenomai.org/?p=xenomai-jki.git;a=commit;h=6b40653e9c3c4a2433bb4e91344fc378eb860f75 >>>>>>>>>>>> >>>>>>>>>>>> Author: Jan Kiszka >>>>>>>>>>>> Date: Wed Feb 10 13:24:29 2010 +0100 >>>>>>>>>>>> >>>>>>>>>>>> Make xnarch_init_timeconv an uninlined weak function >>>>>>>>>>>> >>>>>>>>>>>> Otherwise the wrong set of time conversion variables might get >>>>>>>>>>>> initialized when using > 1 skin libraries. >>>>>>>>>>> If that would be possible, then it is the conversion variables which >>>>>>>>>>> should made be weak, not the function. >>>>>>>>>>> >>>>>>>>>>> The way I see it, the posix and native skins currently get a different >>>>>>>>>>> set of variables and functions, which works, but with your change, since >>>>>>>>>>> there is only one function, only one set of variable gets initialized by >>>>>>>>>>> the two function calls. And one skin just broke. >>>>>>>>>>> >>>>>>>>>>> Or am I missing something? Does the patch fix a problem you really had? >>>>>>>>>> Frankly, I wasn't able to test in the field yet as replacing the libs >>>>>>>>>> there is non-trivial. But I was able to observe that only one set of >>>>>>>>>> functions is used - which is logical considering the weak marks. And >>>>>>>>>> this breaks due to the static inline initialization. >>>>>>>>>> >>>>>>>>>> However, let's mark both functions and variables weak to fix the issue >>>>>>>>>> and avoid leaving unused variables around. Will update my patch in a minute. >>>>>>>>> Ok. I am reverting this patch until you provide me with another >>>>>>>>> solution. It causes latency to segfault purely and simply at startup on >>>>>>>>> my dual PIII. >>>>>>>>> >>>>>>>> Cannot reproduce yet. Do you have a backtrace? >>>>>>> No. But the problem is probably the same as the one signaled by Henri, >>>>>>> a misplaced weak directive ending up in a symbol with no address at all. >>>>>>> Since the current situation works, I am going to wait for the "clean" >>>>>>> fix which puts some code/data in the src/skins/common directory. >>>>>>> >>>>>> Find it in my tree. But it's not yet well tested. >>>>> I do not like it either. Functions which are in src/skins/common should >>>>> still be weak, since this lib is included in all the skins libraries. >>>> Those functions are now in libxeno_common only, so I see no point in >>>> allowing them to be overloaded. >>> Yes, but libxeno_common is included in libpthread_rt.so and >>> libnative.so. So, if you link with both libraries, you get >>> libxeno_common twice. >>> >> Do we link libxeno_common statically? Otherwise, this conflict is not >> logical to me. Also, there are other symbols in bind.c that are non-weak. > > libxeno_common is a "convenience library", which means that when > libpthread_rt.so is assembled, the object files from libxeno_common are > included. BTW, what speaks against making it a dynamic library? > > I guess the loader eliminates the duplicates. > It has to. For the same reason, we should be able to clean up skins/common/current.c now. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux