[clang-19] amdgpu: stack frame exceeds limit in display_mode_vba_30

[nvinson]

Both linux-6.11.3 and linux-6.11.3-gentoo fail to build with clang-19 when CONFIG_DRM_AMD_DC is set to 'y' in the kernel configuration. The Linux kernel builds properly with the same configuration when compiled with gcc or clang-18.

To reproduce:

1. Download linux sources 6.11.3 (or if on a Gentoo system, emerge gentoo-sources-6.11.3)
2. Configure kernel to build AMD_DC (example configs provided) and LLVM=1
3. Build the kernel with 'make LLVM=1'
4. Observe build failure

Expected the kernel to build, but it fails with the error:

drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn30/display_mode_vba_30.c:3540:6: error: stack frame size (2104) exceeds limit (2048) in 'dml30_ModeSupportAndSystemConfigurationFull' [-Werror,-Wframe-larger-than]
 3540 | void dml30_ModeSupportAndSystemConfigurationFull(struct display_mode_lib *mode_lib)                              
      |      ^                                                                                                           
1 error generated.
make[6]: *** [scripts/Makefile.build:244: drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn30/display_mode_vba_30.o] Error 1 
make[5]: *** [scripts/Makefile.build:485: drivers/gpu/drm/amd/amdgpu] Error 2                                            
make[4]: *** [scripts/Makefile.build:485: drivers/gpu/drm] Error 2                                                       
make[3]: *** [scripts/Makefile.build:485: drivers/gpu] Error 2                                                           
make[2]: *** [scripts/Makefile.build:485: drivers] Error 2                                                               
make[1]: *** [/usr/src/linux-6.11.3-gentoo/Makefile:1934: .] Error 2                                                     
make: *** [Makefile:224: __sub-make] Error 2                                                                             

Additional Information:
In case it proves useful, the output of emerge --info is provided below:

Portage 3.0.66.1 (python 3.12.7-final-0, default/linux/amd64/23.0/llvm, gcc-14, glibc-2.40-r5, 6.11.3-gentoo x86_64)
=================================================================
System uname: Linux-6.11.3-gentoo-x86_64-AMD_Ryzen_9_7950X_16-Core_Processor-with-glibc2.40
KiB Mem:   130964756 total, 125707948 free
KiB Swap:    7340028 total,   7340028 free
Timestamp of repository gentoo: Mon, 14 Oct 2024 22:18:22 +0000
Head commit of repository gentoo: ec192d259907f1b8d6b88d8a103aeb1fc1bb5433

Timestamp of repository brother-overlay: Tue, 08 Oct 2024 15:51:03 +0000
Head commit of repository brother-overlay: 928bbe8f324720cbb3dd74c3db524c0e674f1349

Head commit of repository magpie: 30946e5fca7d138cfe692096f6232b53312a5dd0

sh bash 5.2_p37
ld GNU ld (Gentoo 2.43 p2) 2.43.1
app-misc/pax-utils:        1.3.8::gentoo
app-shells/bash:           5.2_p37::gentoo
dev-build/autoconf:        2.13-r8::gentoo, 2.72-r1::gentoo
dev-build/automake:        1.17-r1::gentoo
dev-build/cmake:           3.30.5::gentoo
dev-build/libtool:         2.5.3::gentoo
dev-build/make:            4.4.1-r100::gentoo
dev-build/meson:           1.5.2::gentoo
dev-java/java-config:      2.3.4::gentoo
dev-lang/perl:             5.40.0::gentoo
dev-lang/python:           3.12.7_p1::gentoo, 3.13.0::gentoo
dev-lang/rust:             1.81.0::gentoo
sys-apps/baselayout:       2.15::gentoo
sys-apps/openrc:           0.55.1::gentoo
sys-apps/sandbox:          2.39::gentoo
sys-devel/binutils:        2.43-r1::gentoo
sys-devel/binutils-config: 5.5.2::gentoo
sys-devel/clang:           18.1.8::gentoo, 19.1.1::gentoo
sys-devel/gcc:             14.2.1_p20240921::gentoo
sys-devel/gcc-config:      2.11::gentoo
sys-devel/lld:             18.1.8::gentoo, 19.1.1::gentoo
sys-devel/llvm:            18.1.8-r4::gentoo, 19.1.1::gentoo
sys-kernel/linux-headers:  6.11::gentoo (virtual/os-headers)
sys-libs/glibc:            2.40-r5::gentoo
Repositories:

gentoo
    location: /var/db/repos/gentoo
    sync-type: git
    sync-uri: https://github.com/gentoo-mirror/gentoo.git
    priority: -1000
    volatile: False

brother-overlay
    location: /var/db/repos/brother-overlay
    sync-type: git
    sync-uri: https://github.com/gentoo-mirror/brother-overlay.git
    masters: gentoo
    volatile: False

magpie
    location: /var/db/repos/magpie
    sync-type: git
    sync-uri: https://github.com/nvinson/magpie.git
    masters: gentoo
    volatile: False

Binary Repositories:

gentoobinhost
    priority: 1
    sync-uri: https://distfiles.gentoo.org/releases/amd64/binpackages/23.0/x86-64

ACCEPT_KEYWORDS="amd64 ~amd64"
ACCEPT_LICENSE="* -@EULA"
ADDR2LINE="llvm-addr2line"
AR="llvm-ar"
AS="clang -c"
CBUILD="x86_64-pc-linux-gnu"
CC="clang"
CFLAGS="-march=native -O3 -pipe -flto=thin"
CHOST="x86_64-pc-linux-gnu"
CONFIG_PROTECT="/etc /opt/brother/scanner/brscan4/brsanenetdevice4.cfg /usr/lib64/libreoffice/program/sofficerc /usr/share/gnupg/qualified.txt /var/bind"
CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/dconf /etc/env.d /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/revdep-rebuild /etc/sandbox.d /etc/texmf/language.dat.d /etc/texmf/language.def.d /etc/texmf/updmap.d /etc/texmf/web2c"
CPP="clang-cpp"
CXX="clang++"
CXXFLAGS="-march=native -O3 -pipe -flto=thin"
DISTDIR="/var/cache/portage/distfiles"
EMERGE_DEFAULT_OPTS="--autounmask-backtrack=y --quiet-build"
ENV_UNSET="CARGO_HOME DBUS_SESSION_BUS_ADDRESS DISPLAY GDK_PIXBUF_MODULE_FILE GOBIN GOPATH PERL5LIB PERL5OPT PERLPREFIX PERL_CORE PERL_MB_OPT PERL_MM_OPT XAUTHORITY XDG_CACHE_HOME XDG_CONFIG_HOME XDG_DATA_HOME XDG_RUNTIME_DIR XDG_STATE_HOME"
FCFLAGS="-march=native -O3 -pipe"
FEATURES="assume-digests binpkg-docompress binpkg-dostrip binpkg-logs binpkg-multi-instance buildpkg-live config-protect-if-modified distlocks ebuild-locks fixlafiles ipc-sandbox merge-sync merge-wait multilib-strict network-sandbox news parallel-fetch pid-sandbox pkgdir-index-trusted preserve-libs protect-owned qa-unresolved-soname-deps sandbox sfperms strict unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox usersync xattr"
FFLAGS="-march=native -O3 -pipe"
GENTOO_MIRRORS="http://distfiles.gentoo.org"
LANG="en_US.utf8"
LD="ld.lld"
LDFLAGS="-Wl,-O1 -Wl,--as-needed -Wl,-z,pack-relative-relocs -Wl,--as-needed"
LEX="flex"
MAKEOPTS="-j32"
NM="llvm-nm"
OBJCOPY="llvm-objcopy"
OBJDUMP="llvm-objdump"
PKGDIR="/var/cache/binpkgs"
PORTAGE_CONFIGROOT="/"
PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --omit-dir-times --compress --force --whole-file --delete --stats --human-readable --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages --exclude=/.git"
PORTAGE_TMPDIR="/var/tmp"
RANLIB="llvm-ranlib"
READELF="llvm-readelf"
SHELL="/bin/zsh"
STRINGS="llvm-strings"
STRIP="llvm-strip"
USE="X a52 aac acl acpi alsa amd64 branding bzip2 cairo cdda cdr cet clang cleartype corefonts crypt cups dbus dri dts dvd dvdr elogind encode exif flac gdbm gif glamor gpm gtk gui iconv icu ipv6 jpeg kf6compat lcms libnotify libtirpc llvm-libunwind lto mad mng mp3 mp4 mpeg multilib ncurses nls ogg opengl openmp pam pango pcre pdf png policykit ppds qt5 readline sdl seccomp sound spell ssl startup-notification svg test-rust theora tiff truetype udev udisks unicode upower usb vaapi vorbis vpx vulkan wxwidgets x264 xattr xcb xft xml xv xvid zlib" ABI_X86="64" ADA_TARGET="gcc_12" APACHE2_MODULES="authn_core authz_core socache_shmcb unixd actions alias auth_basic authn_anon authn_dbm authn_file authz_dbm authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir env expires ext_filter file_cache filter headers include info log_config logio mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias" CALLIGRA_FEATURES="karbon sheets words" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" CPU_FLAGS_X86="aes avx avx2 avx512_bf16 avx512_bitalg avx512_vbmi2 avx512_vnni avx512_vpopcntdq avx512bw avx512cd avx512dq avx512f avx512ifma avx512vbmi avx512vl f16c fma3 mmx mmxext pclmul popcnt rdrand sha sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 vpclmulqdq" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock greis isync itrax mtk3301 ntrip navcom oceanserver oncore rtcm104v2 rtcm104v3 sirf skytraq superstar2 tsip tripmate tnt ublox" GUILE_SINGLE_TARGET="3-0" GUILE_TARGETS="3-0" INPUT_DEVICES="libinput" KERNEL="linux" L10N="en-US en" LCD_DEVICES="bayrad cfontz glk hd44780 lb216 lcdm001 mtxorb text" LUA_SINGLE_TARGET="lua5-1" LUA_TARGETS="lua5-1" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php8-2" POSTGRES_TARGETS="postgres16" PYTHON_SINGLE_TARGET="python3_12" PYTHON_TARGETS="python3_12" RUBY_TARGETS="ruby32" VIDEO_CARDS="amdgpu radeonsi" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipp2p iface geoip fuzzy condition tarpit sysrq proto logmark ipmark dhcpmac delude chaos account"
Unset:  ARFLAGS, ASFLAGS, CCLD, CONFIG_SHELL, CPPFLAGS, CTARGET, CXXFILT, ELFEDIT, EXTRA_ECONF, F77FLAGS, FC, GCOV, GPROF, INSTALL_MASK, LC_ALL, LFLAGS, LIBTOOL, LINGUAS, MAKE, MAKEFLAGS, PORTAGE_BINHOST, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS, PYTHONPATH, RUSTFLAGS, SIZE, YACC, YFLAGS

[nvinson]

Archive containing files that may also prove useful: 2055.tar.gz

• build-clang-18.log: reference log using clang-18
• build-clang-19.log: log showing error when building with clang-19
• build-clang-19-w-no-error.log: log showing build process for building display_mode_vba_30.o with clang-19.
• config: the original kernel configuration
• config-w-no-error: same configuration as 'config' but disables the Werror flag
• display_mode_vba_30-clang-18.i: Preprocessed file with clang-18.
• display_mode_vba_30-clang-19.i: Preprocessed file with clang-19.
• display_mode_vba_30-clang-18.o: Object file built with clang-18.
• display_mode_vba_30-clang-19.o: Object file built with clang-19.

[ziyao233]

This has been reproduced on eweOS1, I did some bisecting on LLVM and found 2 is the first bad commit.