On Wed, 10 Apr 2024 at 17:39, Pascal Ernster <git@xxxxxxxxxxxxxx> wrote: > > [2024-04-10 16:45] Ard Biesheuvel: > > On Wed, 10 Apr 2024 at 16:30, Pascal Ernster <git@xxxxxxxxxxxxxx> wrote: > >> > >> [2024-04-10 12:06] Ard Biesheuvel: > >>> On Wed, 10 Apr 2024 at 11:03, Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > >>>> > >>>> On Wed, 10 Apr 2024 at 09:00, Pascal Ernster <git@xxxxxxxxxxxxxx> wrote: > >>>>> > >>>>> [2024-04-10 07:34] Borislav Petkov: > >>>>>> On Tue, Apr 09, 2024 at 06:38:53PM +0200, Pascal Ernster wrote: > >>>>>>> Just to make sure this doesn't get lost: This patch causes the kernel to not > >>>>>>> boot on several x86_64 VMs of mine (I haven't tested it on a bare metal > >>>>>>> machine). For details and a kernel config to reproduce the issue, see https://lore.kernel.org/stable/fd186a2b-0c62-4942-bed3-a27d72930310@xxxxxxxxxxxxxx/ > >>>>>> > >>>> > >>> > >>> Based on your XML description, I have extracted the command line > >>> below, to boot a kernel built from the config you provided (but not > >>> using the arch build scripts). I am using the same x86 initramfs I use > >>> for all my boot testing, but that shouldn't make a difference here. > >>> > >>> Both your 'working' and 'broken' kernels work fine for me, both with > >>> and without OVMF firmware, so I'm a bit stuck here. Could you please > >>> try to reproduce using the command line below? > >>> > >>> > >>> /usr/bin/qemu-system-x86_64 -name guest=kernel_issue,debug-threads=on > >>> -machine pc-q35-8.2,usb=off,smm=on,dump-guest-core=off,memory-backend=pc.ram,hpet=off,acpi=on > >>> -accel kvm -cpu host,migratable=on -m size=2097152k -object > >>> '{"qom-type":"memory-backend-ram","id":"pc.ram","size":2147483648}' > >>> -overcommit mem-lock=off -smp 1,sockets=1,cores=1,threads=1 -uuid > >>> 3ef94585-9ed2-464c-97ca-546fe9b42e2d -display none -no-user-config > >>> -nodefaults -rtc base=utc,driftfix=slew -global > >>> kvm-pit.lost_tick_policy=delay -no-shutdown -global > >>> ICH9-LPC.disable_s3=1 -global ICH9-LPC.disable_s4=1 -boot strict=on > >>> -kernel /usr/local/google/home/ardb/linux-build/arch/x86/boot/bzImage > >>> -initrd /usr/local/google/home/ardb/rootfs-x86.cpio.gz -append > >>> 'console=ttyS0,115200 intel_iommu=on lockdown=confidentiality > >>> ia32_emulation=0 usbcore.nousb loglevel=7 > >>> earlyprintk=serial,ttyS0,115200' -device > >>> '{"driver":"pcie-root-port","port":8,"chassis":1,"id":"pci.1","bus":"pcie.0","multifunction":true,"addr":"0x1"}' > >>> -device '{"driver":"pcie-root-port","port":9,"chassis":2,"id":"pci.2","bus":"pcie.0","addr":"0x1.0x1"}' > >>> -device '{"driver":"pcie-root-port","port":10,"chassis":3,"id":"pci.3","bus":"pcie.0","addr":"0x1.0x2"}' > >>> -device '{"driver":"pcie-root-port","port":11,"chassis":4,"id":"pci.4","bus":"pcie.0","addr":"0x1.0x3"}' > >>> -device '{"driver":"pcie-root-port","port":12,"chassis":5,"id":"pci.5","bus":"pcie.0","addr":"0x1.0x4"}' > >>> -device '{"driver":"pcie-root-port","port":13,"chassis":6,"id":"pci.6","bus":"pcie.0","addr":"0x1.0x5"}' > >>> -chardev stdio,id=charserial0 -device > >>> '{"driver":"isa-serial","chardev":"charserial0","id":"serial0","index":0}' > >>> -audiodev '{"id":"audio1","driver":"none"}' -global > >>> ICH9-LPC.noreboot=off -watchdog-action reset -device > >>> '{"driver":"virtio-balloon-pci","id":"balloon0","bus":"pci.4","addr":"0x0"}' > >>> -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny > >>> -msg timestamp=on > >> > >> > >> The error also seems to occur with the /usr/bin/qemu-system-x86_64 > >> command you posted. I can't see the serial output, but I can see the > >> persistent 100% CPU load that only occurs with the broken kernel but not > >> with the kernel where your patch was reverted. > >> > >> I've written a shell script that should allow you to reproduce > >> everything, and I've trimmed down the kernel config (included within the > >> shell script) even further to reduce compile times. Whilst writing the > >> script, I've found that the issue seems to only occur when I boot > >> bzImage, but not when I boot the vmlinux image. > >> > >> Regarding the linker used: When building the kernel using my PKGBUILD, I > >> used mold as linker, but when writing the attached reproducer script, I > >> used the "normal" ld from the Archlinux binutils 2.42-2 package, and I > >> can confirm that the issue also does also occur when binutils is used > >> instead of mold. > >> > >> Running the script in tmpfs takes about 10-15 minutes on an Intel i5 > >> 8500 with sufficient RAM, and it compiles both the "normal" version of > >> the kernel and a version with your patch reverted. > >> > > > > Thanks, this is very helpful. > > You're welcome, thanks for helping with this! :) > > > > However, both bzImage-fixed and bzImage-broken boot happily for me. > > > > I am using > > > > $ gcc -v > > Using built-in specs. > > COLLECT_GCC=gcc > > COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-linux-gnu/13/lto-wrapper > > OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa > > OFFLOAD_TARGET_DEFAULT=1 > > Target: x86_64-linux-gnu > > Configured with: ../src/configure -v --with-pkgversion='Debian > > 13.2.0-10' --with-bugurl=file:///usr/share/doc/gcc-13/README.Bugs > > --enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,m2 > > --prefix=/usr --with-gc6 > > Thread model: posix > > Supported LTO compression algorithms: zlib zstd > > gcc version 13.2.0 (Debian 13.2.0-10) > > > > $ ld -v > > GNU ld (GNU Binutils for Debian) 2.41.90.20240122 > > > > $ qemu-system-x86_64 --version > > QEMU emulator version 8.2.1 (Debian 1:8.2.1+ds-1) > > Copyright (c) 2003-2023 Fabrice Bellard and the QEMU Project developers > > > > You can grab my bzImage here: > > http://files.workofard.com/bzImage-broken > > > > I'm using > > $ gcc -v > Using built-in specs. > COLLECT_GCC=gcc > COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/13.2.1/lto-wrapper > Target: x86_64-pc-linux-gnu > Configured with: /build/gcc/src/gcc/configure > --enable-languages=ada,c,c++,d,fortran,go,lto,m2,objc,obj-c++ > --enable-bootstrap --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib > --mandir=/usr/share/man --infodir=/usr/share/info > --with-bugurl=https://bugs.archlinux.org/ > --with-build-config=bootstrap-lto --with-linker-hash-style=gnu > --with-system-zlib --enable-__cxa_atexit --enable-cet=auto > --enable-checking=release --enable-clocale=gnu --enable-default-pie > --enable-default-ssp --enable-gnu-indirect-function > --enable-gnu-unique-object --enable-libstdcxx-backtrace > --enable-link-serialization=1 --enable-linker-build-id --enable-lto > --enable-multilib --enable-plugin --enable-shared --enable-threads=posix > --disable-libssp --disable-libstdcxx-pch --disable-werror > Thread model: posix > Supported LTO compression algorithms: zlib zstd > gcc version 13.2.1 20230801 (GCC) > > $ ld -v > GNU ld (GNU Binutils) 2.42.0 > > $ qemu-system-x86_64 --version > QEMU emulator version 8.2.2 > Copyright (c) 2003-2023 Fabrice Bellard and the QEMU Project developers > > > You can download my stuff here: > > https://hardfalcon.net/try1/reproduce.sh > https://hardfalcon.net/try1/vmlinux-broken > https://hardfalcon.net/try1/bzImage-broken > https://hardfalcon.net/try1/vmlinux-fixed > https://hardfalcon.net/try1/bzImage-fixed > Please try this patch https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=e7d24c0aa8e678f41457d1304e2091cac6fd1a2e My bad, and apologies for the mixup - I lost track of things and did not realize this fix was not in Linus's tree yet when I asked Greg to pick up the EFI changes. @Kees: can we get this sent to Linus asap please?
