On Wed, Aug 19, 2020 at 10:36 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote: > > On Wed, Aug 19, 2020 at 08:31:51AM -0700, Yonghong Song wrote: > > > > > > On 8/19/20 2:23 AM, Jiri Olsa wrote: > > > The data of compressed section should be aligned to 4 > > > (for 32bit) or 8 (for 64 bit) bytes. > > > > > > The binutils ld sets sh_addralign to 1, which makes libelf > > > fail with misaligned section error during the update as > > > reported by Jesper: > > > > > > FAILED elf_update(WRITE): invalid section alignment > > > > > > While waiting for ld fix, we can fix compressed sections > > > sh_addralign value manually. Is there a bug filed against GNU ld? Link? > > > > > > Adding warning in -vv mode when the fix is triggered: > > > > > > $ ./tools/bpf/resolve_btfids/resolve_btfids -vv vmlinux > > > ... > > > section(36) .comment, size 44, link 0, flags 30, type=1 > > > section(37) .debug_aranges, size 45684, link 0, flags 800, type=1 > > > - fixing wrong alignment sh_addralign 16, expected 8 > > > section(38) .debug_info, size 129104957, link 0, flags 800, type=1 > > > - fixing wrong alignment sh_addralign 1, expected 8 > > > section(39) .debug_abbrev, size 1152583, link 0, flags 800, type=1 > > > - fixing wrong alignment sh_addralign 1, expected 8 > > > section(40) .debug_line, size 7374522, link 0, flags 800, type=1 > > > - fixing wrong alignment sh_addralign 1, expected 8 > > > section(41) .debug_frame, size 702463, link 0, flags 800, type=1 > > > section(42) .debug_str, size 1017571, link 0, flags 830, type=1 > > > - fixing wrong alignment sh_addralign 1, expected 8 > > > section(43) .debug_loc, size 3019453, link 0, flags 800, type=1 > > > - fixing wrong alignment sh_addralign 1, expected 8 > > > section(44) .debug_ranges, size 1744583, link 0, flags 800, type=1 > > > - fixing wrong alignment sh_addralign 16, expected 8 > > > section(45) .symtab, size 2955888, link 46, flags 0, type=2 > > > section(46) .strtab, size 2613072, link 0, flags 0, type=3 > > > ... > > > update ok for vmlinux > > > > > > Another workaround is to disable compressed debug info data > > > CONFIG_DEBUG_INFO_COMPRESSED kernel option. > > > > So CONFIG_DEBUG_INFO_COMPRESSED is required to reproduce the bug, right? > > correct > > > > > I turned on CONFIG_DEBUG_INFO_COMPRESSED in my config and got a bunch of > > build failures. > > > > ld: drivers/crypto/virtio/virtio_crypto_algs.o: unable to initialize > > decompress status for section .debug_info > > ld: drivers/crypto/virtio/virtio_crypto_algs.o: unable to initialize > > decompress status for section .debug_info > > ld: drivers/crypto/virtio/virtio_crypto_algs.o: unable to initialize > > decompress status for section .debug_info > > ld: drivers/crypto/virtio/virtio_crypto_algs.o: unable to initialize > > decompress status for section .debug_info > > drivers/crypto/virtio/virtio_crypto_algs.o: file not recognized: File format > > not recognized > > > > ld: net/llc/llc_core.o: unable to initialize decompress status for section > > .debug_info > > ld: net/llc/llc_core.o: unable to initialize decompress status for section > > .debug_info > > ld: net/llc/llc_core.o: unable to initialize decompress status for section > > .debug_info > > ld: net/llc/llc_core.o: unable to initialize decompress status for section > > .debug_info > > net/llc/llc_core.o: file not recognized: File format not recognized > > > > ... > > > > The 'ld' in my system: > > > > $ ld -V > > GNU ld version 2.30-74.el8 > > Supported emulations: > > elf_x86_64 > > elf32_x86_64 > > elf_i386 > > elf_iamcu > > i386linux > > elf_l1om > > elf_k1om > > i386pep > > i386pe According to Documentation/process/changes.rst, the minimum supported version of GNU binutils for the kernels is 2.23. Can you upgrade to that and confirm that you still observe the issue? I don't want to spend time chasing bugs in old, unsupported versions of GNU binutils, especially as Jiri notes, 2.26 is required for CONFIG_DEBUG_INFO_COMPRESSED. We can always strengthen the Kconfig check for it. Otherwise, I'm not familiar with the observed error message. > > $ > > > > Do you know what is the issue here? > > mine's: GNU ld version 2.32-31.fc31 > > there's version info in commit: > 10e68b02c861 Makefile: support compressed debug info > > Compress the debug information using zlib. Requires GCC 5.0+ or Clang > 5.0+, binutils 2.26+, and zlib. > > cc-ing Nick Desaulniers, author of that patch.. any idea about the error above? > > thanks, > jirka > -- Thanks, ~Nick Desaulniers
