I tried all the COMPRESS= methods available in /etc/initramfs- tools/initramfs.conf in both eoan and bionic.
For each one, I ran: date > date.txt echo date.txt | cpio -oH newc > date.img update-initramfs -u cat initrd.lz4 date.img > initrd.img kvm -m 512 -kernel vmlinuz -initrd initrd.img -append rdinit=/bin/sh The results show that: xz works in both eoan and bionic, gzip and bzip2 regressed in eoan, lzma, lzop and lz4 never worked. === EOAN === Linux kernel x86 boot executable bzImage, version 5.2.0-10-generic (buildd@lgw01-amd64-046) #11-Ubuntu SMP Tue Jul 30 19:19:46 UTC 2019, RO-rootFS, swap_dev 0x8, Normal VGA SIZE FILENAME WORKS? 9016056 vmlinuz 43335408 initrd.xz yes 43339869 initrd.lzma no date.txt 63081861 initrd.bzip2 no date.txt 68362761 initrd.lzop no date.txt 68364423 initrd.gzip no date.txt 77600825 initrd.lz4 kernel panic === BIONIC === Linux kernel x86 boot executable bzImage, version 4.15.0-58-generic (buildd@lcy01-amd64-013) #64-Ubuntu SMP Tue Aug 6 11:12:41 UTC 2019, RO-rootFS, swap_dev 0x7, Normal VGA SIZE FILENAME WORKS? 8302232 vmlinuz 39946592 initrd.xz yes 39942761 initrd.lzma no date.txt 56997316 initrd.bzip2 yes 61043794 initrd.lzop no date.txt 61046528 initrd.gzip yes -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1840945 Title: Concatenated lz4 initrds don't work Status in linux package in Ubuntu: Confirmed Bug description: Concatenating multiple initrds works fine with gzipped initrds. (microcode+gzip+gzip) => the kernel properly decompresses that With lz4, it can't decompress anything after the first lz4: (microcode+lz4+whatever) => it doesn't decompress whatever. To reproduce: Get vmlinuz and initrd.img from an eoan daily build and put them in a directory. Create an lz4 (or gzip or uncompressed cpio, it doesn't matter): # date > date.txt # echo date.txt | cpio -oH newc | lz4 > date.img Concatenate them: # cat initrd.img.original date.img > initrd.img Boot them: # kvm -m 512 -kernel vmlinuz -initrd initrd.img -append rdinit=/bin/sh Then inside kvm: # ls /date.txt The additional file doesn't exist. `dmesg | grep -i initramfs` reports: Trying to unpack rootfs image as initramfs... Initramfs unpacking failed: Decoding failed To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1840945/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
