From owner-freebsd-ports@freebsd.org Thu Sep 1 23:35:37 2016 Return-Path: Delivered-To: freebsd-ports@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 456FCBCCBB7 for ; Thu, 1 Sep 2016 23:35:37 +0000 (UTC) (envelope-from markmi@dsl-only.net) Received: from asp.reflexion.net (outbound-mail-210-32.reflexion.net [208.70.210.32]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id EC92DE9D for ; Thu, 1 Sep 2016 23:35:36 +0000 (UTC) (envelope-from markmi@dsl-only.net) Received: (qmail 5332 invoked from network); 1 Sep 2016 23:36:22 -0000 Received: from unknown (HELO rtc-sm-01.app.dca.reflexion.local) (10.81.150.1) by 0 (rfx-qmail) with SMTP; 1 Sep 2016 23:36:22 -0000 Received: by rtc-sm-01.app.dca.reflexion.local (Reflexion email security v8.00.0) with SMTP; Thu, 01 Sep 2016 19:35:39 -0400 (EDT) Received: (qmail 4485 invoked from network); 1 Sep 2016 23:35:39 -0000 Received: from unknown (HELO iron2.pdx.net) (69.64.224.71) by 0 (rfx-qmail) with (AES256-SHA encrypted) SMTP; 1 Sep 2016 23:35:39 -0000 Received: from [192.168.0.104] (ip70-189-131-151.lv.lv.cox.net [70.189.131.151]) by iron2.pdx.net (Postfix) with ESMTPSA id 01BACEC8F93; Thu, 1 Sep 2016 16:35:33 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Subject: Re: armv6 specific std::async crash from g++6 built a.out [stable/11 -r304943 context; /usr/ports -r421001 context] From: Mark Millard In-Reply-To: <00C57E2B-47EB-4579-9130-8116C9F934A0@dsl-only.net> Date: Thu, 1 Sep 2016 16:35:33 -0700 Content-Transfer-Encoding: quoted-printable Message-Id: <561577BD-0167-4623-B69D-08923E671D5D@dsl-only.net> References: <25A60F75-B228-4C95-A890-8D6A8DA3F2CE@dsl-only.net> <2514E6E1-B405-4C3F-B283-754B948851EF@dsl-only.net> <00C57E2B-47EB-4579-9130-8116C9F934A0@dsl-only.net> To: freebsd-arm , FreeBSD Ports X-Mailer: Apple Mail (2.3124) X-BeenThere: freebsd-ports@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: Porting software to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 01 Sep 2016 23:35:37 -0000 Another top post because I should have kept going with the reductions: = the following ~10 line program also shows the SIGSEGV behavior on armv6 = (an rpi2) for running ./a.out after compiling via g++6. > # more g++6_build_crashes.cpp = = #include = // future, async, launch::async > =20 > static void f() {} > =20 > int main(int, const char* []) > { > auto a0{ std::async( std::launch::async, f ) }; > a0.get(); > return 0; > } It only takes one std::async use to have the problem. So far the above = (and the earlier variants) always crash with SIGSEGV on the rpi2 when = the g++6 compiler is used. As for the compile commands used: > g++6 -g -v -std=3Dc++14 -Wpedantic -Wall -O2 -pthread = -Wl,-rpath=3D/usr/local/lib/gcc6 -mcpu=3Dcortex-a7 = g++6_build_crashes.cpp Omitting the -mcpu=3Dcortex-a7 still get the problem. Using -O0 instead of -O2 still gets the problem. But I'll note that my stable/11 -r304943 build and my ports builds = (usr/ports -r421001 vintage) were/are based on using -mcpu=3Dcortex-a7 . = Also the system clang 3.8.0 was used to build g++6: > GNU C++14 (FreeBSD Ports Collection) version 6.2.0 = (armv6-portbld-freebsd11.0) > compiled by GNU C version 4.2.1 Compatible FreeBSD Clang 3.8.0 = (tags/RELEASE_380/final 262564), GMP version 5.1.3, MPFR version = 3.1.4-p1, MPC version 1.0.3, isl version none > # more /etc/make.conf=20 > DEFAULT_VERSIONS+=3Dperl5=3D5.22 > WRKDIRPREFIX=3D/usr/obj/portswork > WITH_DEBUG=3D > WITH_DEBUG_FILES=3D > MALLOC_PRODUCTION=3D > # > #system clang 3.8 (gcc6 rejects -march=3Darmv7a): > #CFLAGS+=3D -march=3Darmv7-a -mcpu=3Dcortex-a7 > #CXXFLAGS+=3D -march=3Darmv7-a -mcpu=3Dcortex-a7 > #CPPFLAGS+=3D -march=3Darmv7-a -mcpu=3Dcortex-a7 > # > #lang/gcc6's xgcc stage considers the above conflicting so use just: > CFLAGS+=3D -mcpu=3Dcortex-a7 > CXXFLAGS+=3D -mcpu=3Dcortex-a7 > CPPFLAGS+=3D -mcpu=3Dcortex-a7 =3D=3D=3D Mark Millard markmi at dsl-only.net On 2016-Sep-1, at 4:09 PM, Mark Millard wrote: > This is a top post of an even shorter variant (~14 lines) that gives = little hint of the original program structure but shows the SIGSEGV = behavior: >=20 >> # more g++6_build_crashes.cpp = = =20 >> #include // future, async, launch::async >>=20 >> static void f() {} >>=20 >> int main(int, const char* []) >> { >> auto a0{ std::async( std::launch::async, f ) }; >> auto a1{ std::async( std::launch::async, f ) }; >>=20 >> a0.get(); >> a1.get(); >>=20 >> return 0; >> } >=20 >=20 > The backtraces of the 3 threads look like: >=20 >> (gdb) info threads >> Id Target Id Frame=20 >> 1 LWP 100265 of process 13188 0x00000000 in ?? () >> * 2 LWP 100269 of process 13188 0x00000000 in ?? () >> 3 LWP 100270 of process 13188 thread_start (curthread=3D0x20812600)= at /usr/src/lib/libthr/thread/thr_create.c:253 >=20 >> (gdb) thread 1 >> [Switching to thread 1 (LWP 100265 of process 13188)] >> #0 0x00000000 in ?? () >> (gdb) bt >> #0 0x00000000 in ?? () >> #1 0x200b1acc in _pthread_once (once_control=3D, = init_routine=3D) at = /usr/src/lib/libthr/thread/thr_once.c:95 >> #2 0x00011d1c in __gthread_once (__func=3D, = __once=3D0x20824030) at = /usr/local/lib/gcc6/include/c++/armv6-portbld-freebsd11.0/bits/gthr-defaul= t.h:699 >> #3 std::call_once(std::once_flag&, void (std::thread::*&&)(), = std::thread*&&) (__f=3D, __once=3D...) at = /usr/local/lib/gcc6/include/c++/mutex:619 >> #4 std::__future_base::_Async_state_commonV2::_M_join = (this=3D0x2082400c) at /usr/local/lib/gcc6/include/c++/future:1644 >> #5 std::__future_base::_Async_state_commonV2::_M_complete_async = (this=3D0x2082400c) at /usr/local/lib/gcc6/include/c++/future:1642 >> #6 0x00012d4c in std::__future_base::_State_baseV2::wait = (this=3D0x2082400c) at /usr/local/lib/gcc6/include/c++/future:325 >> #7 std::__basic_future::_M_get_result (this=3D0xbfbfed38) at = /usr/local/lib/gcc6/include/c++/future:687 >> #8 std::future::get (this=3Dthis@entry=3D0xbfbfed38) at = /usr/local/lib/gcc6/include/c++/future:852 >> #9 0x000115a4 in main () at g++6_build_crashes.cpp:10 >=20 >> (gdb) thread 2 >> [Switching to thread 2 (LWP 100269 of process 13188)] >> #0 0x00000000 in ?? () >> (gdb) bt >> #0 0x00000000 in ?? () >> #1 0x200b1acc in _pthread_once (once_control=3D, = init_routine=3D) at = /usr/src/lib/libthr/thread/thr_once.c:95 >> #2 0x00012960 in __gthread_once (__func=3D, = __once=3D0x20824024) at = /usr/local/lib/gcc6/include/c++/armv6-portbld-freebsd11.0/bits/gthr-defaul= t.h:699 >> #3 std::call_once = ()>*, bool*), std::__future_b >> ase::_State_baseV2*, = std::function ()>*, = bool*>(std::once_flag&, void (std::__future_base::_State_baseV2:: >> *&&)(std::function ()>*, bool*), = std::__future_base::_State_baseV2*&&, = std::function> __future_base::_Result_base, = std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) = (__f=3D, __once=3D...) at = /usr/local/lib/gcc6/include/c++/mutex:619 >> #4 = std::__future_base::_State_baseV2::_M_set_result(std::function ()>, bool) = (__ignore_failure=3Dfalse,=20 >> __res=3D..., this=3D0x2082400c) at = /usr/local/lib/gcc6/include/c++/future:393 >> #5 std::__future_base::_Async_state_impl, void>::_Async_state_impl(std::_Bind_simple&&)::{lambda()#1}::operator()() const (__closure=3D0x2082500c) >> at /usr/local/lib/gcc6/include/c++/future:1664 >> #6 = std::_Bind_simple, void>::_Async_state_impl(std::_Bind_simple&&)::{lambda()#1} ()>::_M_invoke<>(std::_Index_tupl >> e<>) (this=3D0x2082500c) at = /usr/local/lib/gcc6/include/c++/functional:1400 >> #7 = std::_Bind_simple, void>::_Async_state_impl(std::_Bind_simple&&)::{lambda()#1} ()>::operator()() ( >> this=3D0x2082500c) at = /usr/local/lib/gcc6/include/c++/functional:1389 >> #8 = std::thread::_State_impl, = void>::_Async_state_impl(std::_Bind_simple&&)::{lambda()#1} ()> >::_ >> M_run() (this=3D0x20825008) at = /usr/local/lib/gcc6/include/c++/thread:196 >> #9 0x201ac464 in std::execute_native_thread_routine (__p=3D0x20825008)= at = /usr/obj/portswork/usr/ports/lang/gcc6/work/gcc-6.2.0/libstdc++-v3/src/c++= 11/thread.cc:83 >> #10 0x200a8fd4 in thread_start (curthread=3D) at = /usr/src/lib/libthr/thread/thr_create.c:289 >> #11 0x200a8a90 in _pthread_create (thread=3D0xbfbfed0c, = attr=3D, start_routine=3D, arg=3D) at /usr/src/lib/libthr/thread/thr_create.c:185 >> #12 0x00000000 in ?? () >> Backtrace stopped: previous frame identical to this frame (corrupt = stack?) >=20 >> (gdb) thread 3 >> [Switching to thread 3 (LWP 100270 of process 13188)] >> #0 thread_start (curthread=3D0x20812600) at = /usr/src/lib/libthr/thread/thr_create.c:253 >> 253 { >> (gdb) bt >> #0 thread_start (curthread=3D0x20812600) at = /usr/src/lib/libthr/thread/thr_create.c:253 >> #1 0x200a8a90 in _pthread_create (thread=3D0xbfbfed0c, = attr=3D, start_routine=3D, arg=3D) at /usr/src/lib/libthr/thread/thr_create.c:185 >> #2 0x00000000 in ?? () >> Backtrace stopped: previous frame identical to this frame (corrupt = stack?) >=20 >=20 > =3D=3D=3D > Mark Millard > markmi at dsl-only.net >=20 > On 2016-Sep-1, at 8:29 AM, Mark Millard = wrote: >=20 >> On 2016-Sep-1, at 7:46 AM, Mark Millard = wrote: >>=20 >>> [I've only compared armv6 and amd64 behavior for this. amd64 did not = get the problem.] >>>=20 >>> The program is under 40 lines and is shown below: >>> (It is a simplification of the context of the original discovery.) >>>=20 >>>> # more g++6_build_crashes.cpp=20 >>>> #include // vector >>>> #include // future, async, launch::async >>>> #include // thread::hardware_concurrency >>>>=20 >>>> decltype(std::thread::hardware_concurrency()) static = parallel_count{0u}; >>>>=20 >>>> static void take_time_measurements() {} >>>>=20 >>>> int main(int, const char* []) >>>> { >>>> parallel_count =3D std::thread::hardware_concurrency(); >>>> // Do not presume more threads than this are possible. >>>>=20 >>>> if (1 < parallel_count) >>>> { >>>> --parallel_count; // leave room for main's thread. >>>>=20 >>>> std::vector> parallels{}; >>>> parallels.reserve(parallel_count); >>>>=20 >>>> parallels.emplace_back >>>> ( std::async( std::launch::async, take_time_measurements ) = ); >>>>=20 >>>> parallels.emplace_back >>>> ( std::async( std::launch::async, take_time_measurements ) = ); >>>>=20 >>>> for (auto const& at : parallels) >>>> { at.wait(); } >>>>=20 >>>> for (auto& at : parallels) >>>> { at.get(); } >>>> } >>>> return 0; >>>> } >>=20 >> The rpi2 gets 4=3D=3Dstd::thread::hardware_concurrency(). >>=20 >> So the typo in the if test is not involved: 2 < parallel_count should = have been in place. Changing it does not change the observed rpi2 = SIGSEGV behavior. >>=20 >> I'll note that it is the second std::async's call chain that gets the = SIGSEGV. >>=20 >>> I do not know if the problem is a bad interaction between FreeBSD's = -pthread and g++6's library code vs. if this is strictly a g++6 library = problem somehow specific to armv6. >>>=20 >>> g++6 based builds run fine in my amd64 context (FreeBSD stable/11 = under VirtualBox under Mac OS X). >>>=20 >>> The clang++ 3.8.0 system compiler based build works fine on both = amd64 and armv6 (an rpi2). >>>=20 >>> Builds via g++6 on the rpi2 produce an a.out that fails as shown = below (SIGSEGV): >>>=20 >>>> # /usr/local/bin/gdb ./a.out >>>> GNU gdb (GDB) 7.11.1 [GDB v7.11.1 for FreeBSD] >>>> Copyright (C) 2016 Free Software Foundation, Inc. >>>> License GPLv3+: GNU GPL version 3 or later = >>>> This is free software: you are free to change and redistribute it. >>>> There is NO WARRANTY, to the extent permitted by law. Type "show = copying" >>>> and "show warranty" for details. >>>> This GDB was configured as "armv6-portbld-freebsd11.0". >>>> Type "show configuration" for configuration details. >>>> For bug reporting instructions, please see: >>>> . >>>> Find the GDB manual and other documentation resources online at: >>>> . >>>> For help, type "help". >>>> Type "apropos word" to search for commands related to "word"... >>>> Reading symbols from ./a.out...done. >>>> (gdb) run >>>> Starting program: /root/c_tests/a.out=20 >>>> [New LWP 100255 of process 12266] >>>>=20 >>>> Thread 2 received signal SIGSEGV, Segmentation fault. >>>> [Switching to LWP 100255 of process 12266] >>>> 0x00000000 in ?? () >>>> (gdb) bt >>>> #0 0x00000000 in ?? () >>>> #1 0x200b2acc in _pthread_once (once_control=3D, = init_routine=3D) at = /usr/src/lib/libthr/thread/thr_once.c:95 >>>> #2 0x0001312c in __gthread_once (__func=3D, = __once=3D0x20824024) at = /usr/local/lib/gcc6/include/c++/armv6-portbld-freebsd11.0/bits/gthr-defaul= t.h:699 >>>> #3 std::call_once = ()>*, bool*), std::__future_b >>>> ase::_State_baseV2*, = std::function ()>*, = bool*>(std::once_flag&, void (std::__future_base::_State_baseV2:: >>>> = *&&)(std::function ()>*, bool*), = std::__future_base::_State_baseV2*&&, = std::function>>> __future_base::_Result_base, = std::__future_base::_Result_base::_Deleter> ()>*&&, bool*&&) = (__f=3D, __once=3D...) at = /usr/local/lib/gcc6/include/c++/mutex:619 >>>> #4 = std::__future_base::_State_baseV2::_M_set_result(std::function ()>, bool) = (__ignore_failure=3Dfalse,=20 >>>> __res=3D..., this=3D0x2082400c) at = /usr/local/lib/gcc6/include/c++/future:393 >>>> #5 std::__future_base::_Async_state_impl, void>::_Async_state_impl(std::_Bind_simple&&)::{lambda()#1}::operator()() const (__closure=3D0x2082500c) >>>> at /usr/local/lib/gcc6/include/c++/future:1664 >>>> #6 = std::_Bind_simple, void>::_Async_state_impl(std::_Bind_simple&&)::{lambda()#1} ()>::_M_invoke<>(std::_Index_tupl >>>> e<>) (this=3D0x2082500c) at = /usr/local/lib/gcc6/include/c++/functional:1400 >>>> #7 = std::_Bind_simple, void>::_Async_state_impl(std::_Bind_simple&&)::{lambda()#1} ()>::operator()() ( >>>> this=3D0x2082500c) at = /usr/local/lib/gcc6/include/c++/functional:1389 >>>> #8 = std::thread::_State_impl, = void>::_Async_state_impl(std::_Bind_simple&&)::{lambda()#1} ()> >::_ >>>> M_run() (this=3D0x20825008) at = /usr/local/lib/gcc6/include/c++/thread:196 >>>> #9 0x201ac464 in std::execute_native_thread_routine = (__p=3D0x20825008) at = /usr/obj/portswork/usr/ports/lang/gcc6/work/gcc-6.2.0/libstdc++-v3/src/c++= 11/thread.cc:83 >>>> #10 0x200a9fd4 in thread_start (curthread=3D) at = /usr/src/lib/libthr/thread/thr_create.c:289 >>>> #11 0x200a9a90 in _pthread_create (thread=3D0xbfbfecbc, = attr=3D, start_routine=3D, arg=3D) at /usr/src/lib/libthr/thread/thr_create.c:185 >>>> #12 0x201ac724 in __gthread_create (__args=3D, = __func=3D0x201ac450 , = __threadid=3D0xbfbfec84) >>>> at = /usr/obj/portswork/usr/ports/lang/gcc6/work/.build/armv6-portbld-freebsd11= .0/libstdc++-v3/include/armv6-portbld-freebsd11.0/bits/gthr-default.h:662 >>>> #13 std::thread::_M_start_thread (this=3Dthis@entry=3D0xbfbfecb4, = state=3Dstd::unique_ptr containing 0x20825018) >>>> at = /usr/obj/portswork/usr/ports/lang/gcc6/work/gcc-6.2.0/libstdc++-v3/src/c++= 11/thread.cc:163 >>>> #14 0x000138ec in = std::thread::thread, void>::_Async_state_impl(std::_Bind_simple&&)::{lambda()#1}>(std::__future_ba >>>> se::_Async_state_impl, = void>::_Async_state_impl(std::_Bind_simple&&)::{lambda()#1}&&) (__f=3D, this=3D0xbfbfecb4) >>>> at /usr/local/lib/gcc6/include/c++/thread:136 >>>> #15 std::__future_base::_Async_state_impl, void>::_Async_state_impl(std::_Bind_simple&&) = (__fn=3D, this=3D0x2082404c) >>>> at /usr/local/lib/gcc6/include/c++/future:1661 >>>> #16 = __gnu_cxx::new_allocator, void> = >::construct, void>, std >>>> ::_Bind_simple = >(std::__future_base::_Async_state_impl, = void>*, std::_Bind_simple&&) (this=3D, = __p=3D) >>>> at /usr/local/lib/gcc6/include/c++/ext/new_allocator.h:120 >>>> #17 = std::allocator_traits, void> > = >::construct>>> )>, void>, std::_Bind_simple = >(std::allocator, void> >&, = std::__future_base::_Async_state_impl>>> d (*())()>, void>*, std::_Bind_simple&&) (__a=3D..., = __p=3D) at = /usr/local/lib/gcc6/include/c++/bits/alloc_traits.h:455 >>>> #18 = std::_Sp_counted_ptr_inplace, void>, = std::allocator, voi >>>> d> >, = (__gnu_cxx::_Lock_policy)2>::_Sp_counted_ptr_inplace = >(std::allocator, void> >, std::_Bind_s >>>> imple&&) (__a=3D..., this=3D0x20824040) at = /usr/local/lib/gcc6/include/c++/bits/shared_ptr_base.h:520 >>>> #19 = std::__shared_count<(__gnu_cxx::_Lock_policy)2>::__shared_count, void>, = std::allocator>>> td::_Bind_simple, void> >, std::_Bind_simple >(std::_Sp_make_shared_tag, = std::__future_base::_Async_state_impl, = void>*, std::allocator>>> __future_base::_Async_state_impl, = void> > const&, std::_Bind_simple&&) (__a=3D..., = this=3D) >>>> at /usr/local/lib/gcc6/include/c++/bits/shared_ptr_base.h:615 >>>> #20 = std::__shared_ptr, void>, = (__gnu_cxx::_Lock_policy)2>::__shared_ptr>>> _Bind_simple, void> >, std::_Bind_simple >(std::_Sp_make_shared_tag, = std::allocator, void> > const&, s >>>> td::_Bind_simple&&) (__a=3D..., __tag=3D..., = this=3D) at = /usr/local/lib/gcc6/include/c++/bits/shared_ptr_base.h:1100 >>>> #21 = std::shared_ptr, void> = >::shared_ptr, voi >>>> d> >, std::_Bind_simple >(std::_Sp_make_shared_tag, = std::allocator, void> > const&, std::_Bind_simple& >>>> &) (__a=3D..., __tag=3D..., this=3D) at = /usr/local/lib/gcc6/include/c++/bits/shared_ptr.h:319 >>>> #22 = std::allocate_shared, void>, = std::allocator, void> >, st >>>> d::_Bind_simple = >(std::allocator, void> > const&, std::_Bind_simple&&) = (__a=3D...) >>>> at /usr/local/lib/gcc6/include/c++/bits/shared_ptr.h:620 >>>> #23 = std::make_shared, void>, std::_Bind_simple = >(std::_Bind_simple&&) () >>>> at /usr/local/lib/gcc6/include/c++/bits/shared_ptr.h:636 >>>> #24 std::__future_base::_S_make_async_state >(std::_Bind_simple&&) (__fn=3D) = at /usr/local/lib/gcc6/include/c++/future:1702 >>>> #25 std::async = (__policy=3D__policy@entry=3Dstd::launch::async, __fn=3D@0x120d8: {void = (void)} 0x120d8 ) at = /usr/local/lib/gcc6/include/c++/future:1716 >>>> #26 0x00011788 in main () at g++6_build_crashes.cpp:25 >>>> (gdb) >>>=20 >>>=20 >>> Context: >>>=20 >>>> # uname -apKU >>>> FreeBSD rpi2 11.0-PRERELEASE FreeBSD 11.0-PRERELEASE #5 r304943M: = Sun Aug 28 03:17:54 PDT 2016 = markmi@FreeBSDx64:/usr/obj/clang/arm.armv6/usr/src/sys/RPI2-NODBG arm = armv6 1100502 1100502 >>>=20 >>>> # svnlite info /usr/src | grep "Re[vl][ai:]" >>>> Relative URL: ^/stable/11 >>>> Revision: 304943 >>>> Last Changed Rev: 304943 >>>=20 >>>> # svnlite info /usr/ports | grep "Re[vl][ai:]" >>>> Relative URL: ^/head >>>> Revision: 421001 >>>> Last Changed Rev: 421001 >>>=20 >>>> # more /etc/make.conf=20 >>>> DEFAULT_VERSIONS+=3Dperl5=3D5.22 >>>> WRKDIRPREFIX=3D/usr/obj/portswork >>>> WITH_DEBUG=3D >>>> WITH_DEBUG_FILES=3D >>>> MALLOC_PRODUCTION=3D >>>=20 >>>=20 >>> The compiler -v output is shown in the below: >>> (Removing the -mcpu=3Dcortex-a7 still gets the problem. Using -O0 = instead of -O2 also still gets the problem.) >>>=20 >>>> Script started on Thu Sep 1 06:52:45 2016 >>>> Command: g++6 -g -v -std=3Dc++14 -Wpedantic -Wall -O2 -pthread = -Wl,-rpath=3D/usr/local/lib/gcc6 -mcpu=3Dcortex-a7 = g++6_build_crashes.cpp >>>> Using built-in specs. >>>> COLLECT_GCC=3Dg++6 >>>> = COLLECT_LTO_WRAPPER=3D/usr/local/libexec/gcc6/gcc/armv6-portbld-freebsd11.= 0/6.2.0/lto-wrapper >>>> Target: armv6-portbld-freebsd11.0 >>>> Configured with: = /usr/obj/portswork/usr/ports/lang/gcc6/work/gcc-6.2.0/configure = --disable-multilib --disable-bootstrap --disable-nls = --enable-gnu-indirect-function --libdir=3D/usr/local/lib/gcc6 --libe >>>> xecdir=3D/usr/local/libexec/gcc6 --program-suffix=3D6 = --with-as=3D/usr/local/bin/as --with-gmp=3D/usr/local = --with-gxx-include-dir=3D/usr/local/lib/gcc6/include/c++/ = --with-ld=3D/usr/local/bin/ld --with-pkgversio >>>> n=3D'FreeBSD Ports Collection' --with-system-zlib --disable-libgcj = --enable-languages=3Dc,c++,objc,fortran --prefix=3D/usr/local = --localstatedir=3D/var --mandir=3D/usr/local/man = --infodir=3D/usr/local/info/gcc6 - >>>> -build=3Darmv6-portbld-freebsd11.0 >>>> Thread model: posix >>>> gcc version 6.2.0 (FreeBSD Ports Collection)=20 >>>> COLLECT_GCC_OPTIONS=3D'-g' '-v' '-std=3Dc++14' '-Wpedantic' '-Wall' = '-O2' '-pthread' '-mcpu=3Dcortex-a7' '-shared-libgcc' = '-mtls-dialect=3Dgnu' >>>> /usr/local/libexec/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.0/cc1plus = -quiet -v g++6_build_crashes.cpp -quiet -dumpbase g++6_build_crashes.cpp = -mcpu=3Dcortex-a7 -mtls-dialect=3Dgnu -auxbase g++6_build_cras >>>> hes -g -O2 -Wpedantic -Wall -std=3Dc++14 -version -o = /tmp//cc0nzkwI.s >>>> GNU C++14 (FreeBSD Ports Collection) version 6.2.0 = (armv6-portbld-freebsd11.0) >>>> compiled by GNU C version 4.2.1 Compatible FreeBSD Clang 3.8.0 = (tags/RELEASE_380/final 262564), GMP version 5.1.3, MPFR version = 3.1.4-p1, MPC version 1.0.3, isl version none >>>> GGC heuristics: --param ggc-min-expand=3D93 --param = ggc-min-heapsize=3D119509 >>>> ignoring nonexistent directory = "/usr/local/lib/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.0/../../../../../ar= mv6-portbld-freebsd11.0/include" >>>> #include "..." search starts here: >>>> #include <...> search starts here: >>>> /usr/local/lib/gcc6/include/c++/ >>>> /usr/local/lib/gcc6/include/c++//armv6-portbld-freebsd11.0 >>>> /usr/local/lib/gcc6/include/c++//backward >>>> /usr/local/lib/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.0/include >>>> /usr/local/include >>>> = /usr/local/lib/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.0/include-fixed >>>> /usr/include >>>> End of search list. >>>> GNU C++14 (FreeBSD Ports Collection) version 6.2.0 = (armv6-portbld-freebsd11.0) >>>> compiled by GNU C version 4.2.1 Compatible FreeBSD Clang 3.8.0 = (tags/RELEASE_380/final 262564), GMP version 5.1.3, MPFR version = 3.1.4-p1, MPC version 1.0.3, isl version none >>>> GGC heuristics: --param ggc-min-expand=3D93 --param = ggc-min-heapsize=3D119509 >>>> Compiler executable checksum: 0997b9bc5b083d9cfbb96481fb14adbd >>>> COLLECT_GCC_OPTIONS=3D'-g' '-v' '-std=3Dc++14' '-Wpedantic' '-Wall' = '-O2' '-pthread' '-mcpu=3Dcortex-a7' '-shared-libgcc' = '-mtls-dialect=3Dgnu' >>>> /usr/local/bin/as -v -mcpu=3Dcortex-a7 -mfpu=3Dvfp -meabi=3D5 -o = /tmp//ccx4UQrB.o /tmp//cc0nzkwI.s >>>> GNU assembler version 2.27 (armv6-portbld-freebsd11.0) using BFD = version (GNU Binutils) 2.27 >>>> = COMPILER_PATH=3D/usr/local/libexec/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.= 0/:/usr/local/libexec/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.0/:/usr/local= /libexec/gcc6/gcc/armv6-portbld-freebsd11.0/:/usr/loca >>>> = l/lib/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.0/:/usr/local/lib/gcc6/gcc/ar= mv6-portbld-freebsd11.0/:/usr/local/lib/gcc6/gcc/armv6-portbld-freebsd11.0= /6.2.0/../../../../../armv6-portbld-freebsd11.0/bin/ >>>> = LIBRARY_PATH=3D/usr/local/lib/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.0/:/u= sr/local/lib/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.0/../../../../../armv6= -portbld-freebsd11.0/lib/:/usr/local/lib/gcc6/gcc/armv >>>> 6-portbld-freebsd11.0/6.2.0/../../../:/lib/:/usr/lib/ >>>> COLLECT_GCC_OPTIONS=3D'-g' '-v' '-std=3Dc++14' '-Wpedantic' '-Wall' = '-O2' '-pthread' '-mcpu=3Dcortex-a7' '-shared-libgcc' = '-mtls-dialect=3Dgnu' >>>> = /usr/local/libexec/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.0/collect2 = -plugin = /usr/local/libexec/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.0/liblto_plugin.= so -plugin-opt=3D/usr/local/libexec/gcc6/gcc/armv6 >>>> -portbld-freebsd11.0/6.2.0/lto-wrapper = -plugin-opt=3D-fresolution=3D/tmp//ccD1bSsW.res = -plugin-opt=3D-pass-through=3D-lgcc_s -plugin-opt=3D-pass-through=3D-lgcc = -plugin-opt=3D-pass-through=3D-lpthread -plugin-opt=3D-pa >>>> ss-through=3D-lc -plugin-opt=3D-pass-through=3D-lgcc_s = -plugin-opt=3D-pass-through=3D-lgcc --eh-frame-hdr -V -dynamic-linker = /libexec/ld-elf.so.1 --hash-style=3Dboth --enable-new-dtags -X = /usr/lib/crt1.o /usr/lib >>>> /crti.o = /usr/local/lib/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.0/crtbegin.o = -L/usr/local/lib/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.0 = -L/usr/local/lib/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.0/../../../ >>>> ../../armv6-portbld-freebsd11.0/lib = -L/usr/local/lib/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.0/../../.. = -rpath=3D/usr/local/lib/gcc6 /tmp//ccx4UQrB.o -lstdc++ -lm -lgcc_s -lgcc = -lpthread -lc -lgcc_s -lgc >>>> c /usr/local/lib/gcc6/gcc/armv6-portbld-freebsd11.0/6.2.0/crtend.o = /usr/lib/crtn.o >>>> GNU ld (GNU Binutils) 2.27 >>>> Supported emulations: >>>=20 >>> . . . >>>=20 >>> I end up having to kill -9 gdb as kill and quit each hang. >>>=20 >>> Just running via ./a.out (no gdb) gets the SIGSEGV but does not = hang. >>>=20 >>=20 >> =3D=3D=3D >> Mark Millard >> markmi at dsl-only.net >>=20 >>=20 >=20 >=20