From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 14766 invoked by alias); 4 Nov 2014 14:41:53 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org Received: (qmail 14741 invoked by uid 48); 4 Nov 2014 14:41:49 -0000 From: "leandrosansilva at gmail dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/63736] New: gcc generated program with segfault on atomic exchange when the atomic variable is a member of a struct allocated with make_shared Date: Tue, 04 Nov 2014 14:41:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c++ X-Bugzilla-Version: 4.8.2 X-Bugzilla-Keywords: X-Bugzilla-Severity: blocker X-Bugzilla-Who: leandrosansilva at gmail dot com X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version bug_status bug_severity priority component assigned_to reporter attachments.created Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2014-11/txt/msg00186.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63736 Bug ID: 63736 Summary: gcc generated program with segfault on atomic exchange when the atomic variable is a member of a struct allocated with make_shared Product: gcc Version: 4.8.2 Status: UNCONFIRMED Severity: blocker Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: leandrosansilva at gmail dot com Created attachment 33882 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33882&action=edit self contained program which reproduces the problem I am sending a sample code with a self contained program which declares a struct called PStruct which contains a variable member which is an atomic of a simple struct. G++ compiles the code correctly, however it has a segmentation fault in a (IMO) valid atomic exchance operation, when PStruct is allocated using make_shared, but it does not happen when it's allocated using new operator. In clang 3.5 the code generate a valid program, which runs as expected. G++ info: Using built-in specs. COLLECT_GCC=g++-4.8 COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.8/lto-wrapper Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.8.1-2ubuntu1~12.04' --with-bugurl=file:///usr/share/doc/gcc-4.8/README.Bugs --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.8 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-amd64 --with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.8.1 (Ubuntu 4.8.1-2ubuntu1~12.04) The command line I am using to compile the code: $ g++-4.8 -std=c++11 -Wall -Wextra atomic_of_struct_test.cpp -o atomic_of_struct_test -lrt -latomic The attached file reproduces the problem, because allocates using make_shared. To allocate using new operator, comment line 34 and uncomment line 37. The expected output in both allocation ways is: field1: 2, field2: 4 The actual output when compiled with g++ is: Segmentation fault (core dumped) The backtrace of the later execution: #0 0x00007ffff7bd5897 in ?? () from /usr/lib/x86_64-linux-gnu/libatomic.so.1 No symbol table info available. #1 0x0000000000401186 in std::atomic::exchange (this=0x604028, __i=..., _m=std::memory_order_seq_cst) at /usr/include/c++/4.8/atomic:225 tmp = { field1 = 140737488346624, field2 = 4198920 } #2 0x00000000004010e3 in PStruct::setMs (this=0x604028, ms=...) at atomic_of_struct_test.cpp:18 No locals. #3 0x0000000000400f81 in main () at atomic_of_struct_test.cpp:39 ms = { field1 = 2, field2 = 4 } ptr = std::shared_ptr (count 1, weak 0) 0x604028 oms = { field1 = 0, field2 = 4197680 }