[libcxx-commits] [PATCH] D66178: Remove std::shared_ptr::make_shared and std::shared_ptr::allocate_shared

Petr Hosek via Phabricator via libcxx-commits libcxx-commits at lists.llvm.org
Mon Aug 19 00:39:05 PDT 2019 

phosek added a comment.

I started seeing segfaults in some of our tests after the latests Clang roll and bisecting narrowed it down to this change. I also tried reverting this change locally and the segfaults no longer occur so I'm pretty confident it's this change. What's confusing is that it's not happening in regular Clang builds, it's only affecting GCC builds (we're using GCC 8.3) that are using libc++ and ASan builds. It's also don't see any of the modified functions on the stack which makes it even more confusing but I'm suspecting memory corruption that's happens earlier.

Here's one of the symbolized logs:

  [230.404] 01385.01538> <== fatal exception: process /boot/test/sys/fit-test[563923] thread initial-thread[563937]
  [230.404] 01385.01538> <== read not-present page fault, PC at 0x74f079c4d197
  [230.404] 01385.01538>  CS:                   0 RIP:     0x74f079c4d197 EFL:            0x10202 CR2:               0x20
  [230.404] 01385.01538>  RAX:               0x20 RBX:     0x74f079cff2e0 RCX:     0x3c5ec54ec8f0 RDX:                  0
  [230.404] 01385.01538>  RSI:     0x324048b387c0 RDI:               0x30 RBP:     0x3c5ec54ecdb0 RSP:     0x3c5ec54ec7e8
  [230.404] 01385.01538>   R8:                  0  R9: 0xfffff00000ffffff R10:     0x24f17e394991 R11:     0x324048b38780
  [230.404] 01385.01538>  R12:     0x696b9aa4a040 R13:     0x3c5ec54ec870 R14:     0x74f079d00ba0 R15:     0x3c5ec54ec900
  [230.404] 01385.01538>  fs.base:     0x36bebfd9cb38 gs.base:                  0
  [230.404] 01385.01538>  errc:               0x4
  [230.404] 01385.01538> bottom of user stack:
  [230.404] 01385.01538> 0x00003c5ec54ec7e8: 79c71b5e 000074f0 c54ecbe0 00003c5e |^..y.t....N.^<..|
  [230.405] 01385.01538> 0x00003c5ec54ec7f8: c54ec810 00003c5e c54ec8d0 00003c5e |..N.^<....N.^<..|
  [230.405] 01385.01538> 0x00003c5ec54ec808: c54ec8b0 00003c5e 20202020 20202020 |..N.^<..        |
  [230.405] 01385.01538> 0x00003c5ec54ec818: 20202020 20202020 20202020 20202020 |                |
  [230.405] 01385.01538> 0x00003c5ec54ec828: 20202020 20202020 20202020 20202020 |                |
  [230.405] 01385.01538> 0x00003c5ec54ec838: 20202020 00000000 00000000 00000000 |    ............|
  [230.405] 01385.01538> 0x00003c5ec54ec848: c54ec910 00003c5e c54ec890 00003c5e |..N.^<....N.^<..|
  [230.405] 01385.01538> 0x00003c5ec54ec858: c54ec8f0 00003c5e 00000001 00000000 |..N.^<..........|
  [230.405] 01385.01538> 0x00003c5ec54ec868: 00000000 00000000 79cff2e0 000074f0 |...........y.t..|
  [230.405] 01385.01538> 0x00003c5ec54ec878: 00000000 00000000 00000000 00000000 |................|
  [230.405] 01385.01538> 0x00003c5ec54ec888: 00000000 00000000 79cff2e0 000074f0 |...........y.t..|
  [230.405] 01385.01538> 0x00003c5ec54ec898: 00000000 00000000 00000000 00000000 |................|
  [230.405] 01385.01538> 0x00003c5ec54ec8a8: 00000000 00000000 79cff2e0 000074f0 |...........y.t..|
  [230.405] 01385.01538> 0x00003c5ec54ec8b8: 00000000 00000000 00000000 00000000 |................|
  [230.405] 01385.01538> 0x00003c5ec54ec8c8: 00000000 00000000 79cff2e0 000074f0 |...........y.t..|
  [230.405] 01385.01538> 0x00003c5ec54ec8d8: 00000000 00000000 00000000 00000000 |................|
  [230.405] 01385.01538> arch: x86_64
  [230.405] 01385.01538> dso: id=c2d8143ea2273b1ffed2fb43f0047a8dcc93f14a base=0x74f079bfd000 name=app:/boot/test/sys/fit-test
  [230.405] 01385.01538> dso: id=917cbd24458d8ac1421a04344846e76fcd0bf4c4 base=0x6d7b61144000 name=<vDSO>
  [230.405] 01385.01538> dso: id=aa81cd39e8cca017198bdb628a513a94e296acae base=0x696b9aa43000 name=libunittest.so
  [230.405] 01385.01538> dso: id=8a80a62e95a4ced9ca0480796662a90104c505cd base=0x5e934f165000 name=libfdio.so
  [230.405] 01385.01538> dso: id=09aee3d7f0e1245e8a304de42f0f45cbac1a25ee base=0x4437b334a000 name=libc.so
  [230.405] 01385.01538> dso: id=0bb8728bb0bbaa3b base=0x2ab900e61000 name=libc++abi.so.1
  [230.405] 01385.01538> dso: id=b216543249a796e8 base=0x292be29b5000 name=libc++.so.2
  [230.405] 01385.01538> dso: id=6635fc5124abcdd4 base=0x1b1d07b59000 name=libunwind.so.1
  [230.406] 01385.01538>    #1.1  0x000074f079c4d197 in fit::function_impl<16ul, false, void ()>* fit::internal::function_base<16ul, false, void ()>::target<fit::function_impl<16ul, false, void ()> >(bool) ../../out/default.zircon/../../zircon/system/ulib/fit/include/lib/fit/function_internal.h:227 <<VMO#563915=/boot/test/sys/fit->+0x50197 sp 0x3c5ec54ec7e8
  [230.406] 01385.01538>    #1    0x000074f079c4d197 in fit::internal::target<fit::function_impl<16ul, false, void ()>, false, true, void>::get(void*) ../../out/default.zircon/../../zircon/system/ulib/fit/include/lib/fit/function_internal.h:153 <<VMO#563915=/boot/test/sys/fit->+0x50197 sp 0x3c5ec54ec7e8
  [230.406] 01385.01538>    #2.2  0x000074f079c71b5e in void fit::internal::function_base<16ul, false, void ()>::share_with<fit::function_impl<16ul, false, void ()> >(fit::function_impl<16ul, false, void ()>&) ../../out/default.zircon/../../zircon/system/ulib/fit/include/lib/fit/function_internal.h:263 <<VMO#563915=/boot/test/sys/fit->+0x74b5e sp 0x3c5ec54ec7f0
  [230.406] 01385.01538>    #2.1  0x000074f079c71b5e in fit::function_impl<16ul, false, void ()>::share() ../../out/default.zircon/../../zircon/system/ulib/fit/include/lib/fit/function.h:283 <<VMO#563915=/boot/test/sys/fit->+0x74b5e sp 0x3c5ec54ec7f0
  [230.406] 01385.01538>    #2    0x000074f079c71b5e in (anonymous namespace)::sharing() ../../out/default.zircon/../../zircon/system/utest/fit/function_tests.cc:617 <<VMO#563915=/boot/test/sys/fit->+0x74b5e sp 0x3c5ec54ec7f0
  [230.407] 01385.01538>    #3    0x0000696b9aa45157 in unittest_run_test(char const*, bool (*)(), test_info**, bool*) ../../out/default.zircon/../../zircon/system/ulib/unittest/unittest.cc:268 <<VMO#563950=libunittest.so>>+0x2157 sp 0x3c5ec54ecdc0
  [230.407] 01385.01538>    #4.2  0x0000696b9aa45792 in operator() ../../out/default.zircon/../../zircon/system/ulib/unittest/unittest.cc:296 <<VMO#563950=libunittest.so>>+0x2792 sp 0x3c5ec54ece00
  [230.407] 01385.01538>    #4.1  0x0000696b9aa45792 in run_with_watchdog<unittest_run_named_test(char const*, bool (*)(), test_type_t, test_info**, bool*)::<lambda()> > ../../out/default.zircon/../../zircon/system/ulib/unittest/unittest.cc:285 <<VMO#563950=libunittest.so>>+0x2792 sp 0x3c5ec54ece00
  [230.407] 01385.01538>    #4    0x0000696b9aa45792 in unittest_run_named_test ../../out/default.zircon/../../zircon/system/ulib/unittest/unittest.cc:295 <<VMO#563950=libunittest.so>>+0x2792 sp 0x3c5ec54ece00
  [230.407] 01385.01538>    #5    0x000074f079c4e32a in function_tests(bool, char const*) ../../out/default.zircon/../../zircon/system/utest/fit/function_tests.cc:945 <<VMO#563915=/boot/test/sys/fit->+0x5132a sp 0x3c5ec54ece40
  [230.408] 01385.01538>    #6.1  0x0000696b9aa44dc0 in unittest_run_all_tests_etc ../../out/default.zircon/../../zircon/system/ulib/unittest/all-tests.cc:46 <<VMO#563950=libunittest.so>>+0x1dc0 sp 0x3c5ec54ece80
  [230.408] 01385.01538>    #6    0x0000696b9aa44dc0 in unittest_run_all_tests ../../out/default.zircon/../../zircon/system/ulib/unittest/all-tests.cc:207 <<VMO#563950=libunittest.so>>+0x1dc0 sp 0x3c5ec54ece80
  [230.409] 01385.01538>    #7    0x0000696b9aa44ac9 in main ../../out/default.zircon/../../zircon/system/ulib/unittest/unittest-main.cc:15 <<VMO#563950=libunittest.so>>+0x1ac9 sp 0x3c5ec54ecef0
  [230.409] 01385.01538>    #8    0x00004437b337274c in start_main ../../out/default.zircon/../../zircon/third_party/ulib/musl/src/env/__libc_start_main.c:93 <<VMO#563929=ld.so.1>>+0x2874c sp 0x3c5ec54ecf00
  [230.409] 01385.01538>    #9    0x0000000000000000 in <>+0x0 sp 0x3c5ec54ed000


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  rCXX libc++

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