** Description changed: + + [Impact] + + * The kernel changed handling of binfmt-P and that breaks qemu + using binfmt registering TCG based emulators to run foreign + architecture code. + + * This happened late 5.11.0-20 -> 5.13.0-20 and even as of today + cloud-images start with the former :-/ That hides this unless you + properly upgrade and reboot. + + * This was already reported and fixed in 1:6.1+dfsg-5 and this is + backporting this fix + + [Test Plan] + + * Based on the great report and evolving on that there is a small + but very useful test. + 1. System (Kernel + userspace dependent, so it needs to be a VM) + => Get a VM of the target release to test + 2. Install dependencies + $ sudo apt update + $ sudo apt upgrade -y + $ sudo apt install -y qemu-user-static debootstrap + 3. Prep foreign arch chroots for armhf + (other architectures would work as well) + # I tested this with various userspace versions, but behavior + # only depends on kernel + qmeu-user-static + $ sudo debootstrap --foreign --verbose --arch=armhf jammy armTest-J + 4. Run something int he chroot, which will trigger binfmt -> qemu + $ sudo chroot armTest-I echo 1 2 3 + + Bad result: 2 3 + Good case with fix: 1 2 3 + + There also is an extended testcase in the report, but it tests and + achieves the same, so I picked this simpler one. Everyone is welcome to + test his own case once this is up for SRU verification. + + [Where problems could occur] + + * This is changing binfmt integration for qemu-user-static, so of the + many things qemu does we do not have to think about classic + virtualization or even emulation. Only cross arch emulation through + binfmt (like the test examples with qemu-user-static + foreign arch + debootstrap) are what will be affected. + + [Other Info] + + * Older qemu seems non-affected by using binfmt differently back then. + * While this is actually a regression-by-kernel I want to fix this in + qemu, the new qemu code works fine with the older kernel behavior as + well. + + + ---- ---- ---- + Problem with qemu-arm-static version 1:6.0+dfsg-2expubuntu1, as of recent Impish When using qemu-arm-static for cross-debootstrap for an ARM machine argument 0 of the invoked ARM program does not contain the name of the executable but argument 1, argument 2 is passed as argument 1 and so forth. Thus all program calls are missing the 1st argument. Eample: A shell script test.sh -- Start -------------------- #!/bin/sh echo "\$0=$0" echo "\$1=$1" echo "\$2=$2" echo "\$*=$*" -- End -------------------- Running the script as "./test.sh a bb ccc dddd" emits: $0=./test.sh $1=a $2=bb $*=a bb ccc dddd Reproduce the erroneous behavior of qemu-arm-static Create a directory armTest. Enter: sudo debootstrap --foreign --verbose --arch=armhf impish armTest sudo cp test.sh armTest sudo cp -v /usr/bin/qemu-arm-static armTest/usr/bin Now run sudo chroot armTest ./test.sh a bb ccc dddd The script is now run by the shell for the ARM architecture, and is invoked by qemu-arm-static. The script now emits $0=a $1=bb $2=ccc $*=bb ccc dddd argument 0 (the program name) disappeared, and all arguments are shifted up. Evidence that actually qemu-arm-static is the culprit: In /etc/apt/sources.list add the hirsute main, main-update, universe and universe-update repositories. Enter: sudo apt-get update sudo apt-get install qemu-user-static/hirsute Confirm that you want to downgrade the program to version 1:5.2+dfsg-9ubuntu3.2 (of hirsute-update). Copy the downgraded qemu-arm-static to armTest/usr/bin. Repeat the chroot command. Now the result is the same as invoking test.sh directly under your x86_64 architecture. This bug does not only affect shell scripts. Apparently all programs are affected by the shifted program arguments. This bug makes a complete cross-debootstrap impossible because the second debootstrap stage is run as chroot in the target architecture. Further steps to prepare a ready-to-boot image/SD card are equally impossible. ProblemType: Bug DistroRelease: Ubuntu 21.10 Package: qemu-user-static 1:6.0+dfsg-2expubuntu1 ProcVersionSignature: Ubuntu 5.13.0-20.20-generic 5.13.14 Uname: Linux 5.13.0-20-generic x86_64 ApportVersion: 2.20.11-0ubuntu70 Architecture: amd64 CasperMD5CheckResult: unknown CurrentDesktop: LXQt Date: Wed Oct 20 13:35:52 2021 KvmCmdLine: COMMAND STAT EUID RUID PID PPID %CPU COMMAND MachineType: VMware, Inc. VMware Virtual Platform ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.13.0-20-generic root=UUID=f5ea75df-ad8e-4112-8537-372efa9f6a4b ro splash quiet SourcePackage: qemu UpgradeStatus: Upgraded to impish on 2021-10-16 (3 days ago) dmi.bios.date: 11/12/2020 dmi.bios.release: 4.6 dmi.bios.vendor: Phoenix Technologies LTD dmi.bios.version: 6.00 dmi.board.name: 440BX Desktop Reference Platform dmi.board.vendor: Intel Corporation dmi.board.version: None dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 1 dmi.chassis.vendor: No Enclosure dmi.chassis.version: N/A dmi.ec.firmware.release: 0.0 dmi.modalias: dmi:bvnPhoenixTechnologiesLTD:bvr6.00:bd11/12/2020:br4.6:efr0.0:svnVMware,Inc.:pnVMwareVirtualPlatform:pvrNone:sku:rvnIntelCorporation:rn440BXDesktopReferencePlatform:rvrNone:cvnNoEnclosure:ct1:cvrN/A: dmi.product.name: VMware Virtual Platform dmi.product.version: None dmi.sys.vendor: VMware, Inc.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1947860 Title: qemu-arm-static swallows the program name, and shifts all arguments left To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1947860/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
