Date: Sat, 6 Jun 2015 17:24:43 +0100 From: Gary Palmer <gpalmer@freebsd.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: Andre Meiser <ortadur@web.de>, freebsd-stable@freebsd.org Subject: Re: Many core dumps in pthread_getspecific. Message-ID: <20150606162443.GA29089@in-addr.com> In-Reply-To: <20150606150821.GG2499@kib.kiev.ua> 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> <20150606150821.GG2499@kib.kiev.ua>
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On Sat, Jun 06, 2015 at 06:08:21PM +0300, Konstantin Belousov wrote: > 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. lib/libkse/thread/thr_kern.c is longer and has a _get_curthread() call around line 601. Regards, Gary > 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.
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