[Lldb-commits] [PATCH] D76569: Convert CommandObjectCommands functions to return StringRefs

Tue Mar 24 02:39:51 PDT 2020

jankratochvil added a comment.

In D76569#1938577 <https://reviews.llvm.org/D76569#1938577>, @labath wrote:

> I wouldn't be too worried about asan as a StringRef provides the same lifetime guarantees (== none) as a const char *.

That's true but ASAN failed for me for the first patch. But that looks as some GCC bug which I cannot reproduce on a minimal testcase.

  =================================================================
  ==722160==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7fffffffa4c0 at pc 0x7fffd9c605fc bp 0x7fffffff9cc0 sp 0x7fffffff9cb0
  READ of size 1 at 0x7fffffffa4c0 thread T0
      #0 0x7fffd9c605fb in void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char const*>(char const*, char const*, std::forward_iterator_tag) (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/../lib/liblldb.so.11git+0x28d45fb)
      #1 0x7fffdb165322 in lldb_private::CommandObject::CommandObject(lldb_private::CommandInterpreter&, llvm::StringRef, llvm::StringRef, llvm::StringRef, unsigned int) (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/../lib/liblldb.so.11git+0x3dd9322)
      #2 0x7fffdb16aed0 in lldb_private::CommandObjectRegexCommand::CommandObjectRegexCommand(lldb_private::CommandInterpreter&, llvm::StringRef, llvm::StringRef, llvm::StringRef, unsigned int, unsigned int, bool) (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/../lib/liblldb.so.11git+0x3ddeed0)
      #3 0x7fffe2c933c7 in CommandObjectCommandsAddRegex::DoExecute(lldb_private::Args&, lldb_private::CommandReturnObject&) (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/../lib/liblldb.so.11git+0xb9073c7)
      #4 0x7fffdb160ae1 in lldb_private::CommandObjectParsed::Execute(char const*, lldb_private::CommandReturnObject&) (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/../lib/liblldb.so.11git+0x3dd4ae1)
      #5 0x7fffdb149b62 in lldb_private::CommandInterpreter::HandleCommand(char const*, lldb_private::LazyBool, lldb_private::CommandReturnObject&, lldb_private::ExecutionContext*, bool, bool) (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/../lib/liblldb.so.11git+0x3dbdb62)
      #6 0x7fffdb14f1dc in lldb_private::CommandInterpreter::IOHandlerInputComplete(lldb_private::IOHandler&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&) (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/../lib/liblldb.so.11git+0x3dc31dc)
      #7 0x7fffdad58e63 in lldb_private::IOHandlerEditline::Run() (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/../lib/liblldb.so.11git+0x39cce63)
      #8 0x7fffdacc8321 in lldb_private::Debugger::RunIOHandlers() (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/../lib/liblldb.so.11git+0x393c321)
      #9 0x7fffdb1032fc in lldb_private::CommandInterpreter::RunCommandInterpreter(bool, bool, lldb_private::CommandInterpreterRunOptions&) (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/../lib/liblldb.so.11git+0x3d772fc)
      #10 0x7fffd9e53e6b in lldb::SBDebugger::RunCommandInterpreter(bool, bool) (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/../lib/liblldb.so.11git+0x2ac7e6b)
      #11 0x4134c6 in Driver::MainLoop() (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/lldb+0x4134c6)
      #12 0x42339d in main (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/lldb+0x42339d)
      #13 0x7fffd544f1a2 in __libc_start_main ../csu/libc-start.c:308
      #14 0x4078ad in _start (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/lldb+0x4078ad)

  Address 0x7fffffffa4c0 is located in stack of thread T0 at offset 944 in frame
      #0 0x7fffe2c92aa3 in CommandObjectCommandsAddRegex::DoExecute(lldb_private::Args&, lldb_private::CommandReturnObject&) (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/../lib/liblldb.so.11git+0xb906aa3)

    This frame has 39 object(s):
      [32, 33) '<unknown>'
      [48, 49) '<unknown>'
      [64, 65) '<unknown>'
      [80, 81) '<unknown>'
      [96, 97) '<unknown>'
      [112, 113) '<unknown>'
      [128, 129) '<unknown>'
      [144, 145) '<unknown>'
      [160, 161) '<unknown>'
      [176, 177) '<unknown>'
      [192, 193) '<unknown>'
      [208, 209) '<unknown>'
      [224, 225) '<unknown>'
      [240, 241) '<unknown>'
      [256, 264) '<unknown>'
      [288, 304) '<unknown>'
      [320, 336) 'name' (line 990)
      [352, 368) '<unknown>'
      [384, 400) '<unknown>'
      [416, 432) 'io_handler_sp' (line 999)
      [448, 464) '<unknown>'
      [480, 496) '<unknown>'
      [512, 528) '<unknown>'
      [544, 560) '<unknown>'
      [576, 592) '<unknown>'
      [608, 624) '<unknown>'
      [640, 656) '<unknown>'
      [672, 688) '<unknown>'
      [704, 720) '<unknown>'
      [736, 752) '<unknown>'
      [768, 784) '<unknown>'
      [800, 816) '<unknown>'
      [832, 848) '<unknown>'
      [864, 880) '<unknown>'
      [896, 912) 'cmd_sp' (line 1130)
      [928, 960) '<unknown>' <== Memory access at offset 944 is inside this variable
      [992, 1024) '<unknown>'
      [1056, 1096) 'error' (line 989)
      [1136, 1176) '<unknown>'
  HINT: this may be a false positive if your program uses some custom stack unwind mechanism, swapcontext or vfork
        (longjmp and C++ exceptions *are* supported)
  SUMMARY: AddressSanitizer: stack-use-after-scope (/quad/home/jkratoch/redhat/llvm-monorepo2-gccassertdebugasan/bin/../lib/liblldb.so.11git+0x28d45fb) in void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char const*>(char const*, char const*, std::forward_iterator_tag)
  Shadow bytes around the buggy address:
    0x10007fff7440: 01 f2 00 f2 f2 f2 00 00 f2 f2 00 00 f2 f2 00 00
    0x10007fff7450: f2 f2 00 00 f2 f2 00 00 f2 f2 00 00 f2 f2 00 00
    0x10007fff7460: f2 f2 00 00 f2 f2 00 00 f2 f2 00 00 f2 f2 f8 f8
    0x10007fff7470: f2 f2 00 00 f2 f2 00 00 f2 f2 00 00 f2 f2 00 00
    0x10007fff7480: f2 f2 00 00 f2 f2 f8 f8 f2 f2 f8 f8 f2 f2 00 00
  =>0x10007fff7490: f2 f2 00 00 f2 f2 f8 f8[f8]f8 f2 f2 f2 f2 f8 f8
    0x10007fff74a0: f8 f8 f2 f2 f2 f2 00 00 00 00 00 f2 f2 f2 f2 f2
    0x10007fff74b0: 00 00 00 00 00 f3 f3 f3 f3 f3 00 00 00 00 00 00
    0x10007fff74c0: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
    0x10007fff74d0: f8 f8 f2 f2 f8 f8 f2 f2 f8 f8 f2 f2 f8 f8 f2 f2
    0x10007fff74e0: f8 f8 f2 f2 f8 f8 f2 f2 f8 f8 f2 f2 00 00 f2 f2
  Shadow byte legend (one shadow byte represents 8 application bytes):
    Addressable:           00
    Partially addressable: 01 02 03 04 05 06 07
    Heap left redzone:       fa
    Freed heap region:       fd
    Stack left redzone:      f1
    Stack mid redzone:       f2
    Stack right redzone:     f3
    Stack after return:      f5
    Stack use after scope:   f8
    Global redzone:          f9
    Global init order:       f6
    Poisoned by user:        f7
    Container overflow:      fc
    Array cookie:            ac
    Intra object redzone:    bb
    ASan internal:           fe
    Left alloca redzone:     ca
    Right alloca redzone:    cb
    Shadow gap:              cc
  ==722160==ABORTING

  cmake ../llvm-monorepo/llvm/ -DCMAKE_BUILD_TYPE=Debug  -DLLVM_USE_LINKER=gold -DLLVM_ENABLE_PROJECTS="lldb;clang;lld"  -DLLVM_USE_SPLIT_DWARF=ON -DCMAKE_EXE_LINKER_FLAGS="-fuse-ld=gold  -Wl,--gdb-index" -DCMAKE_SHARED_LINKER_FLAGS="-fuse-ld=gold  -Wl,--gdb-index" -DLLVM_ENABLE_ASSERTIONS=ON  -DLLVM_OPTIMIZED_TABLEGEN=ON -DLLVM_USE_SANITIZER=Address
  # Producer is GNU C++14 9.2.1 20190827 (Red Hat 9.2.1-1) -mtune=generic -march=x86-64 -g -gsplit-dwarf -O1 -std=c++14 -fPIC -fvisibility-inlines-hidden -fno-omit-frame-pointer -fsanitize=address -fsanitize-address-use-after-scope -fno-exceptions -fno-rtti.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D76569/new/

https://reviews.llvm.org/D76569