Hello, A data point for this bug, from initramfs-tools 0.151 in Debian testing.
Our installer writes /etc/initramfs-tools/conf.d/resume, as Debian's does, and Debian resumes from it with no resume= on the kernel command line. For a swap partition that works. A swap file also needs its offset, and 0.151 does not read RESUME_OFFSET from that file. Its init takes resume_offset only from the kernel command line, or from a conf.d snippet inside the image. Measured in a virtual machine with a swap file at offset 3821568, configured only in conf.d/resume, with no resume= or resume_offset= on the command line. After boot the kernel's resume offset was 0. With an initramfs hook that writes resume_offset=3821568 into the image's conf/conf.d, it was 3821568, and a full hibernate and resume cycle from the swap file passed. Would you take RESUME_OFFSET in conf.d/resume, read like RESUME (initramfs.conf(5)), with resume_offset= on the command line still taking precedence? We can send it as a merge request on salsa if that is welcome. This message was written with AI assistance; I directed and verified the measurements. Daniel Ramos
