search

llvm / llvm-project

The LLVM Project is a collection of modular and reusable compiler and toolchain technologies.
http://llvm.org
Other
28.65k stars 11.84k forks source link

crash with --emit-relocs and --strip-debug when debug sections present #44223

Closed kees closed 2 years ago

kees commented 4 years ago
Bugzilla Link 44878
Resolution FIXED
Resolved on Apr 15, 2020 23:00
Version unspecified
OS Linux
Blocks llvm/llvm-project#44654
CC @MaskRay,@nathanchance,@nickdesaulniers,@rui314,@smithp35,@stephenhines,@tstellar
Fixed by commit(s) 6c73246179376442705b3a545f4e1f1478777a04 489a7356cca373de761ada4c06c5b43edc581b4b

Extended Description

Combining --emit-relocs with --strip-debug on an object with debug sections will crash during orphan placement:

$ echo "a;" > test.c $ clang -g -c -o test.o test.c ... $ objdump -wh test.o

test.o: file format elf64-x86-64

Sections: Idx Name Size VMA LMA File off Algn Flags 0 .text 00000000 0000000000000000 0000000000000000 00000040 22 CONTENTS, ALLOC, LOAD, READONLY, CODE 1 .debug_str 00000091 0000000000000000 0000000000000000 00000040 20 CONTENTS, READONLY, DEBUGGING 2 .debug_abbrev 0000002c 0000000000000000 0000000000000000 000000d1 20 CONTENTS, READONLY, DEBUGGING 3 .debug_info 0000003b 0000000000000000 0000000000000000 000000fd 20 CONTENTS, RELOC, READONLY, DEBUGGING 4 .comment 0000006a 0000000000000000 0000000000000000 00000138 20 CONTENTS, READONLY 5 .note.GNU-stack 00000000 0000000000000000 0000000000000000 000001a2 20 CONTENTS, READONLY 6 .debug_line 0000002e 0000000000000000 0000000000000000 000001a2 20 CONTENTS, READONLY, DEBUGGING 7 .llvm_addrsig 00000000 0000000000000000 0000000000000000 00000320 20 CONTENTS, READONLY, EXCLUDE

$ ld.lld --emit-relocs --strip-debug -o /dev/null test.o Stack dump:

  1. Program arguments: ld.lld --emit-relocs --strip-debug -o /dev/null test.o

    ​0 0x000055a6d904b68e llvm::sys::PrintStackTrace(llvm::raw_ostream&) (/home/kees/src/llvm-build/x86/bin/lld+0x51168e)

    ​1 0x000055a6d9049514 llvm::sys::RunSignalHandlers() (/home/kees/src/llvm-build/x86/bin/lld+0x50f514)

    ​2 0x000055a6d9049658 SignalHandler(int) (/home/kees/src/llvm-build/x86/bin/lld+0x50f658)

    ​3 0x00007fe35d416540 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x15540)

    ​4 0x000055a6d9028122 llvm::Twine::printOneChild(llvm::raw_ostream&, llvm::Twine::Child, llvm::Twine::NodeKind) const (/home/kees/src/llvm-build/x86/bin/lld+0x4ee122)

    ​5 0x000055a6d90282a1 llvm::Twine::toVector(llvm::SmallVectorImpl&) const (/home/kees/src/llvm-build/x86/bin/lld+0x4ee2a1)

    ​6 0x000055a6d902834b llvm::Twine::str[abi:cxx11]() const (/home/kees/src/llvm-build/x86/bin/lld+0x4ee34b)

    ​7 0x000055a6d9261a9f lld::elf::getOutputSectionName(lld::elf::InputSectionBase const*) (/home/kees/src/llvm-build/x86/bin/lld+0x727a9f)

    ​8 0x000055a6d91a8a5e lld::elf::LinkerScript::addOrphanSections()::'lambda'(lld::elf::InputSectionBase)::operator()(lld::elf::InputSectionBase) const (/home/kees/src/llvm-build/x86/bin/lld+0x66ea5e)

    ​9 0x000055a6d91a6177 lld::elf::LinkerScript::addOrphanSections() (/home/kees/src/llvm-build/x86/bin/lld+0x66c177)

    ​10 0x000055a6d912ce0e void lld::elf::LinkerDriver::link<llvm::object::ELFType<(llvm::support::endianness)1, true> >(llvm::opt::InputArgList&) (/home/kees/src/llvm-build/x86/bin/lld+0x5f2e0e)

    ​11 0x000055a6d8f7c833 lld::elf::LinkerDriver::main(llvm::ArrayRef<char const*>) (/home/kees/src/llvm-build/x86/bin/lld+0x442833)

    ​12 0x000055a6d9130dfb lld::elf::link(llvm::ArrayRef<char const*>, bool, llvm::raw_ostream&, llvm::raw_ostream&) (/home/kees/src/llvm-build/x86/bin/lld+0x5f6dfb)

    ​13 0x000055a6d8f79ede main (/home/kees/src/llvm-build/x86/bin/lld+0x43fede)

    ​14 0x00007fe35ce921e3 __libc_start_main /build/glibc-4WA41p/glibc-2.30/csu/../csu/libc-start.c:342:3

    ​15 0x000055a6d900aa4e _start (/home/kees/src/llvm-build/x86/bin/lld+0x4d0a4e)

    Segmentation fault (core dumped)

nathanchance commented 2 years ago

mentioned in issue llvm/llvm-bugzilla-archive#45553

tstellar commented 2 years ago

mentioned in issue llvm/llvm-project#44654

nathanchance commented 4 years ago

Bug llvm/llvm-bugzilla-archive#45553 has been marked as a duplicate of this bug.

MaskRay commented 4 years ago

Committed 489a7356cca373de761ada4c06c5b43edc581b4b to release/10.x

(I was waiting for someone in charge to do this ... )

Android also cherry picked the commit (r377782d)

MaskRay commented 4 years ago

git cherry-pick -n 6c73246179376442705b3a545f4e1f1478777a04

is safe in release/10.x and I am in favor of the cherry-pick.

nathanchance commented 4 years ago

lld 10.0.0 will be broken with the Linux kernel after https://git.kernel.org/bpf/bpf-next/c/af73d78bd384aa9b8789aa6e7ddbb165f971276f (x86_64 defconfig specifically), which will be in 5.7-rc1.

Can we please have 6c73246179376442705b3a545f4e1f1478777a04 merged into LLVM 10.0.1, where I have verified that it builds, fixes the issue, and passes the test it added?

MaskRay commented 4 years ago

Fixed by 6c73246179376442705b3a545f4e1f1478777a04 (will be included in lld 11)

MaskRay commented 4 years ago

Posted https://reviews.llvm.org/D74510

MaskRay commented 4 years ago

Looking

There is an assertion error in

void LinkerScript::addOrphanSections() { ... StringRef name = getOutputSectionName(s);

(https://reviews.llvm.org/D66704 disallows --strip-all + --emit-relocs)

kees commented 4 years ago

assigned to @MaskRay