Date: Sat, 6 Jun 2015 18:08:21 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Andre Meiser <ortadur@web.de> Cc: freebsd-stable@freebsd.org Subject: Re: Many core dumps in pthread_getspecific. Message-ID: <20150606150821.GG2499@kib.kiev.ua> In-Reply-To: <trinity-7650c105-1bf9-4919-aab8-9f06c63b45a7-1433577022434@3capp-webde-bs58> References: <trinity-d3a62468-a8fd-44c3-ab9c-8b177ca8a366-1433331244003@3capp-webde-bs60> <20150603145838.GX2499@kib.kiev.ua> <trinity-7650c105-1bf9-4919-aab8-9f06c63b45a7-1433577022434@3capp-webde-bs58>
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On Sat, Jun 06, 2015 at 09:50:22AM +0200, Andre Meiser wrote: > On Wed, Jun 03, 2015 at 16:58 +0200, Konstantin Belousov wrote: > > You should recompile both libc and libthr with debugging symbols, like > > cd /usr/src > > (cd lib/libc && make all install DEBUG_FLAGS=-g) > > (cd lib/libthr && make all install DEBUG_FLAGS=-g) > > then obtain the core dump and post backtraces. > > Thank you, that was exactly what I was looking for. Now I like FreeBSD > even more. ;) > > I made this short after and also rebooted the entire system to make > all programmes use those debug libs. Since than I had not a single > core dump. Which means, most likely, that your installation was corrupted. > > I experienced something similar in the past, that with activated > debugging some errors can't be triggered any longer. > > At the moment I'm happy without crashes and I can work with this > system. As soon as I'm getting a new core dump, I'll post the > backtrace. If this won't happen for weeks, I may recompile the libs > again, try to find a way to trigger the bug on purpose, enable the > debug flag again and than provide the info. > > In the meantime, maybe a core developer may think about the lines > of code I'd provided. Why is _get_curthread() compared to NULL at > thr_kern.c (line 601) but not at thr_spec.c (line 224)? Either > _get_curthread() never ever returns NULL, than it's pointless to test > it or it's missing [not only] at thr_spec.c. Whole thr_kern.c file is 213 lines long in the HEAD. Might be, a core developer has a 601-lines long thr_kern.c. The only way for _get_curthread() to return NULL or, more likely, a garbage, is for the call to _get_curthread() to happens before the threading machinery was initialized. WRT the thr_spec.c, correct code must call pthread_key_create(3) at least once before calling any other pthread_key_*(3) functions. The implementation of pthread_key_create(3) interface, the function _pthread_key_create(), calls _thr_check_init() as the first action, and this helper initializes threading. So if _get_curthread() in any pthread_key_*() function returns NULL or garbage, this is an application' bug. > > I'm using activated hyperthreading: > > % sysctl hw.model hw.machine hw.ncpu hw.model: Intel(R) Xeon(R) CPU > E5-1620 v2 @ 3.70GHz hw.machine: amd64 hw.ncpu: 8 > > Sincerely yours Andre. _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable To > unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org"
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