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Groups > linux.debian.bugs.dist > #1286030
| From | Steven Shiau <steven@spider.nchc.org.tw> |
|---|---|
| Newsgroups | linux.debian.bugs.dist, linux.debian.kernel |
| Subject | Bug#1130775: Regression: MDRAID 1.2 superblock created in Kernel 6.19 is rejected by older kernels (-EINVAL) |
| Date | 2026-03-15 05:00 +0100 |
| Message-ID | <MyKNY-7Bmp-3@gated-at.bofh.it> (permalink) |
| Organization | linux.* mail to news gateway |
Cross-posted to 2 groups.
Package: src:linux Version: 6.19.6+deb14-amd64 Severity: important Description: We have identified a forward-compatibility regression in the md subsystem introduced between Linux Kernel 6.18 and 6.19. When creating a standard RAID 1 array using mdadm, the resulting superblock generated under Kernel 6.19 is violently rejected by older enterprise Linux kernels (e.g., older LTS kernels with version 6.1) with an -EINVAL argument error during assembly. A strict A/B test was performed using Debian Live (based on Sid) environments. The exact same version of mdadm (4.5-5) and the exact same creation command was used in both environments: mdadm --create "/dev/md127" --force --run --level=raid1 --raid-devices=2 --metadata=1.2 --data-offset=34816 --bitmap=internal --assume-clean /dev/nvme0n1p2 /dev/nvme1n1p2 Test 1 (Success): * Environment: Kernel 6.18.15+deb14-amd64 * Result: Array creates successfully. When the machine reboots into the older guest OS, the legacy kernel assembles the array normally. Test 2 (Failure/Regression): * Environment: Kernel 6.19.6+deb14-amd64 * Result: Array creates successfully in the live environment. However, when the machine reboots into the older guest OS, the legacy kernel rejects the component drives with: mdadm: failed to add /dev/nvme1n1p2 to /dev/md/0: Invalid argument. mdadm: failed to add /dev/nvme0n1p2 to /dev/md/0: Invalid argument. mdadm: /dev/md0 assembled from 0 drives Conclusion: Kernel 6.19 appears to be injecting a new feature flag, modifying the bitmap format, or altering the superblock structure during creation in a way that older md_mod drivers cannot parse, breaking backward compatibility for disaster recovery tools restoring older operating systems. Steven
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Bug#1130775: Regression: MDRAID 1.2 superblock created in Kernel 6.19 is rejected by older kernels (-EINVAL) Steven Shiau <steven@spider.nchc.org.tw> - 2026-03-15 05:00 +0100 Bug#1130775: Regression: MDRAID 1.2 superblock created in Kernel 6.19 is rejected by older kernels (-EINVAL) Salvatore Bonaccorso <carnil@debian.org> - 2026-03-15 09:00 +0100 Bug#1130775: Regression: MDRAID 1.2 superblock created in Kernel 6.19 is rejected by older kernels (-EINVAL) Steven Shiau <steven.shiau@niar.org.tw> - 2026-03-19 14:20 +0100 Bug#1130775: Regression: MDRAID 1.2 superblock created in Kernel 6.19 is rejected by older kernels (-EINVAL) Steven Shiau <steven.shiau@niar.org.tw> - 2026-03-19 14:20 +0100
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