WARNING: ram4 appears to be on the same physical disk as ram4.

Status: upstream: reported C repro on 2026/10/23 01:12
Reported-by: syzbot+bc65d9876bcd9b27aeda@syzkaller.appspotmail.com
First crash: 21d, last: 21d

Sample crash report:
device-mapper: raid: Choosing default region size of 4MiB
mdX: WARNING: ram4 appears to be on the same physical disk as ram4.
True protection against single-disk failure might be compromised.
md/raid10:mdX: unsupported raid10 layout: 0x       2
md: pers->run() failed ...
device-mapper: table: 248:0: raid: Failed to run raid array (-EINVAL)
device-mapper: ioctl: error adding target to table

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/23 01:50 linux-6.1.y 79807e970724 b55fad29 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING: ram4 appears to be on the same physical disk as ram4.
2026/10/23 01:11 linux-6.1.y 79807e970724 b55fad29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING: ram4 appears to be on the same physical disk as ram4.
* Struck through repros no longer work on HEAD.