From owner-freebsd-ports@freebsd.org Thu Sep 1 23:09:17 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 2C580BCC565 for ; Thu, 1 Sep 2016 23:09:17 +0000 (UTC) (envelope-from markmi@dsl-only.net) Received: from asp.reflexion.net (outbound-mail-210-22.reflexion.net [208.70.210.22]) (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 E683BCFA for ; Thu, 1 Sep 2016 23:09:16 +0000 (UTC) (envelope-from markmi@dsl-only.net) Received: (qmail 8187 invoked from network); 1 Sep 2016 23:09:56 -0000 Received: from unknown (HELO mail-cs-02.app.dca.reflexion.local) (10.81.19.2) by 0 (rfx-qmail) with SMTP; 1 Sep 2016 23:09:56 -0000 Received: by mail-cs-02.app.dca.reflexion.local (Reflexion email security v8.00.0) with SMTP; Thu, 01 Sep 2016 19:09:01 -0400 (EDT) Received: (qmail 9591 invoked from network); 1 Sep 2016 23:09:01 -0000 Received: from unknown (HELO iron2.pdx.net) (69.64.224.71) by 0 (rfx-qmail) with (AES256-SHA encrypted) SMTP; 1 Sep 2016 23:09:01 -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 5DFAEEC8F93; Thu, 1 Sep 2016 16:09:08 -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: <2514E6E1-B405-4C3F-B283-754B948851EF@dsl-only.net> Date: Thu, 1 Sep 2016 16:09:07 -0700 Content-Transfer-Encoding: quoted-printable Message-Id: <00C57E2B-47EB-4579-9130-8116C9F934A0@dsl-only.net> References: <25A60F75-B228-4C95-A890-8D6A8DA3F2CE@dsl-only.net> <2514E6E1-B405-4C3F-B283-754B948851EF@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 23:09:17 -0000 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: > # 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; > } The backtraces of the 3 threads look like: > (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 > (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 > (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?) > (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?) =3D=3D=3D Mark Millard markmi at dsl-only.net On 2016-Sep-1, at 8:29 AM, Mark Millard wrote: > 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