[PATCH] D102296: [ELF] getRelocatedSection: remove the check for ET_REL object file

Mon Aug 30 16:01:05 PDT 2021

nickdesaulniers added a comment.

I've got a disassembler assertion failure when disassembling a Linux kernel built with thinLTO that bisects back to this commit.

  llvm-objdump: ../include/llvm/ADT/ArrayRef.h:196: ArrayRef<T> llvm::ArrayRef<unsigned char>::slice(size_t, size_t) const [T = unsigned char]: Assertion `N+M <= size() && "Invalid specifier"' failed.
  PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace.
  Stack dump:
  0.      Program arguments: llvm-objdump -dr vmlinux
   #0 0x00000000016f4b7a llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /android0/llvm-project/llvm/build/../lib/Support/Unix/Signals.inc:565:11
   #1 0x00000000016f4d2b PrintStackTraceSignalHandler(void*) /android0/llvm-project/llvm/build/../lib/Support/Unix/Signals.inc:632:1
   #2 0x00000000016f33f3 llvm::sys::RunSignalHandlers() /android0/llvm-project/llvm/build/../lib/Support/Signals.cpp:97:5
   #3 0x00000000016f5455 SignalHandler(int) /android0/llvm-project/llvm/build/../lib/Support/Unix/Signals.inc:407:1
   #4 0x00007f622df59140 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14140)
   #5 0x00007f622da31ce1 raise ./signal/../sysdeps/unix/sysv/linux/raise.c:51:1
   #6 0x00007f622da1b537 abort ./stdlib/abort.c:81:7
   #7 0x00007f622da1b40f get_sysdep_segment_value ./intl/loadmsgcat.c:509:8
   #8 0x00007f622da1b40f _nl_load_domain ./intl/loadmsgcat.c:970:34
   #9 0x00007f622da2a662 (/lib/x86_64-linux-gnu/libc.so.6+0x34662)
  #10 0x0000000000f15340 llvm::ArrayRef<unsigned char>::slice(unsigned long, unsigned long) const /android0/llvm-project/llvm/build/../include/llvm/ADT/ArrayRef.h:0:7
  #11 0x0000000000ee9fbd disassembleObject(llvm::Target const*, llvm::object::ObjectFile const*, llvm::MCContext&, llvm::MCDisassembler*, llvm::MCDisassembler*, llvm::MCInstrAnalysis const*, llvm::MCInstPrinter*, llvm::MCSubtargetInfo const*, llvm::MCSubtargetInfo const*, (anonymous namespace)::PrettyPrinter&, llvm::objdump::SourcePrinter&, bool) /android0/llvm-project/llvm/build/../tools/llvm-objdump/llvm-objdump.cpp:1437:51
  #12 0x0000000000ee72ee disassembleObject(llvm::object::ObjectFile const*, bool) /android0/llvm-project/llvm/build/../tools/llvm-objdump/llvm-objdump.cpp:1711:1
  #13 0x0000000000ee56f0 dumpObject(llvm::object::ObjectFile*, llvm::object::Archive const*, llvm::object::Archive::Child const*) /android0/llvm-project/llvm/build/../tools/llvm-objdump/llvm-objdump.cpp:2352:7
  #14 0x0000000000ee2dd2 dumpInput(llvm::StringRef) /android0/llvm-project/llvm/build/../tools/llvm-objdump/llvm-objdump.cpp:2432:5
  #15 0x0000000000f40a99 void (*std::for_each<__gnu_cxx::__normal_iterator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, void (*)(llvm::StringRef)>(__gnu_cxx::__normal_iterator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, __gnu_cxx::__normal_iterator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, void (*)(llvm::StringRef)))(llvm::StringRef) /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/bits/stl_algo.h:3838:33
  #16 0x0000000000ef4e6b void (*llvm::for_each<std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > >&, void (*)(llvm::StringRef)>(std::vector<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > >&, void (*)(llvm::StringRef)))(llvm::StringRef) /android0/llvm-project/llvm/build/../include/llvm/ADT/STLExtras.h:1541:3
  #17 0x0000000000ee1268 main /android0/llvm-project/llvm/build/../tools/llvm-objdump/llvm-objdump.cpp:2708:3
  #18 0x00007f622da1cd0a __libc_start_main ./csu/../csu/libc-start.c:308:16
  #19 0x0000000000edcb9a _start (/android0/llvm-project/llvm/build/bin/llvm-objdump+0xedcb9a)
  [1]    2784195 abort      llvm-objdump -dr vmlinux

Indeed, if I revert 8ec73e96b72d04787ed606cfbb62a7a2a05b3711 <https://reviews.llvm.org/rG8ec73e96b72d04787ed606cfbb62a7a2a05b3711>, I can disassemble my kernel again. This is blocking debugging of https://lore.kernel.org/lkml/5913cdf4-9c8e-38f8-8914-d3b8a3565d73@kernel.org/.  This is a 49M binary; my employer makes sharing files excessively difficult...
https://github.com/ClangBuiltLinux/linux/issues/1446

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D102296/new/

https://reviews.llvm.org/D102296