thinlto: Crash during final link

[arndb]

A randconfig kernel build triggered this bug in llvm during the final link:

ld.lld -m elf_x86_64 --thinlto-cache-dir=.thinlto-cache -mllvm -import-instr-limit=5 -r -o vmlinux.o -T .tmp_initcalls.lds -T .tmp_symversions.lds --whole-archive arch/x86/kernel/head_64.o arch/x86/kernel/head64.o arch/x86/kernel/ebda.o arch/x86/kernel/platform-quirks.o init/built-in.a usr/built-in.a arch/x86/built-in.a kernel/built-in.a certs/built-in.a mm/built-in.a fs/built-in.a ipc/built-in.a security/built-in.a crypto/built-in.a block/built-in.a lib/built-in.a arch/x86/lib/built-in.a lib/lib.a arch/x86/lib/lib.a drivers/built-in.a sound/built-in.a virt/built-in.a arch/x86/pci/built-in.a arch/x86/power/built-in.a --no-whole-archive --start-group --end-group
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace.
Stack dump:
0. Running pass 'Function Pass Manager' on module 'mm/built-in.a(gup.o at 2432)'.

1. Running pass 'CodeGen Prepare' on function '@internal_get_user_pages_fast'
   #0 0x00007f3f3aee90e3 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0xc020e3)
   auto update fork #1 0x00007f3f3aee74d0 llvm::sys::RunSignalHandlers() (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0xc004d0)
   automated testing #2 0x00007f3f3aee974a (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0xc0274a)
   clang validates extended assembly constraints even when -fno-integrated-as is set #3 0x00007f3f3fa7e160 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14160)
   support for "r" prefixed variables in ARM inline assembly #4 0x00007f3f3bf5455b llvm::LoopBase<llvm::BasicBlock, llvm::Loop>::getLoopLatch() const (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0x1c6d55b)
   VLAIS in ExoFS #5 0x00007f3f3b0ee3bf (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0xe073bf)
   support for asm goto #6 0x00007f3f3b0decda (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0xdf7cda)
   __builtin_constant_p() does not work in deep inline functions #7 0x00007f3f3b0d5613 (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0xdee613)
   -Wvla in __compiletime_assert #8 0x00007f3f3b00ef7d llvm::FPPassManager::runOnFunction(llvm::Function&) (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0xd27f7d)
   invalid -fmerge-all-constants #9 0x00007f3f3b014a63 llvm::FPPassManager::runOnModule(llvm::Module&) (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0xd2da63)
   removed null pointer checks #10 0x00007f3f3b00f5cf llvm::legacy::PassManagerImpl::run(llvm::Module&) (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0xd285cf)
   arm64 kvm built with clang doesn't boot #11 0x00007f3f3c076737 (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0x1d8f737)
   assembly: unrecognized token in .rept directive #12 0x00007f3f3c0774f6 (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0x1d904f6)
   [arm64] missing "S" constraint #13 0x00007f3f3c07734b llvm::lto::thinBackend(llvm::lto::Config const&, unsigned int, std::function<std::unique_ptr<llvm::lto::NativeObjectStream, std::default_deletellvm::lto::NativeObjectStream > (unsigned int)>, llvm::Module&, llvm::ModuleSummaryIndex const&, llvm::StringMap<std::unordered_set<unsigned long, std::hash, std::equal_to, std::allocator >, llvm::MallocAllocator> const&, llvm::DenseMap<unsigned long, llvm::GlobalValueSummary*, llvm::DenseMapInfo, llvm::detail::DenseMapPair<unsigned long, llvm::GlobalValueSummary*> > const&, llvm::MapVector<llvm::StringRef, llvm::BitcodeModule, llvm::DenseMap<llvm::StringRef, unsigned int, llvm::DenseMapInfollvm::StringRef, llvm::detail::DenseMapPair<llvm::StringRef, unsigned int> >, std::vector<std::pair<llvm::StringRef, llvm::BitcodeModule>, std::allocator<std::pair<llvm::StringRef, llvm::BitcodeModule> > > >&, std::vector<unsigned char, std::allocator > const&) (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0x1d9034b)
   CONFIG_STACK_VALIDATION=y HOSTCC=clang #14 0x00007f3f3c071778 (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0x1d8a778)
   i915 driver compiler crash #15 0x00007f3f3c07143d (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0x1d8a43d)
   CONFIG_CC_STACKPROTECTOR_STRONG=y and CONFIG_PARAVIRT=y issue #16 0x00007f3f3ae95c8f (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0xbaec8f)
   missing gcov support #17 0x00007f3f3ae79367 (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0xb92367)
   function attribute no_stack_protector #18 0x00007f3f3fa7b45f __pthread_once_slow ./nptl/pthread_once.c:118:7
   integrated assembler does not support variable assignment #19 0x00007f3f3ae79300 (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0xb92300)
   -fzero-call-used-regs=used-gpr #20 0x00007f3f3ae95a3d (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0xbaea3d)
   Memory exhausted with integrated assembler #21 0x00007f3f3ae95539 (/lib/x86_64-linux-gnu/libLLVM-13.so.1+0xbae539)
   clang crash compiling binder.o for 32b x86 #22 0x00007f3f3a1a8774 (/lib/x86_64-linux-gnu/libstdc++.so.6+0xda774)
   [llvm-as] unknown token in expression  #23 0x00007f3f3fa73430 start_thread ./nptl/pthread_create.c:474:7
   -Wreturn-stack-address in _THIS_IP_ and current_text_addr #24 0x00007f3f39e8ed03 __clone ./misc/../sysdeps/unix/sysv/linux/x86_64/clone.S:97:0
   Segmentation fault (core dumped)

Full object files attached here:
link-time-crash.tar.xz.gz

I see this happen with lld version 1:13~++20210306104456+7ae191f59f0f-1exp120210306095217.256

[nickdesaulniers]

I see this happen with lld version 1:13~++20210306104456+7ae191f59f0f-1exp120210306095217.256

2021-03-06

I just tested with llvm @ 8ace12130526f450c822ca232d1f865b247d7434 (2021-06-26) and wasn't able to repro:

$ wget https://github.com/ClangBuiltLinux/linux/files/6096101/link-time-crash.tar.xz.gz
$ gunzip link-time-crash.tar.xz.gz
$ tar xvf link-time-crash.tar.xz
$ cd git/arm-soc/build/x86/0xF108A65C_defconfig/
$ ld.lld -m elf_x86_64 --thinlto-cache-dir=.thinlto-cache -mllvm -import-instr-limit=5 -r -o vmlinux.o -T .tmp_initcalls.lds -T .tmp_symversions.lds --whole-archive arch/x86/kernel/head_64.o arch/x86/kernel/head64.o arch/x86/kernel/ebda.o arch/x86/kernel/platform-quirks.o init/built-in.a usr/built-in.a arch/x86/built-in.a kernel/built-in.a certs/built-in.a mm/built-in.a fs/built-in.a ipc/built-in.a security/built-in.a crypto/built-in.a block/built-in.a lib/built-in.a arch/x86/lib/built-in.a lib/lib.a arch/x86/lib/lib.a drivers/built-in.a sound/built-in.a virt/built-in.a arch/x86/pci/built-in.a arch/x86/power/built-in.a --no-whole-archive --start-group --end-group
$ echo $?
0

Perhaps this was fixed between March and now. Thanks anyways for the report.