mdadm fails with "Unable to initialize sysfs" since 6.17.0 rc0

[jelly]

In rawhide the testNotRemovingDisks test fails

> warn: Error starting RAID array: Process reported exit code 1: mdadm: Unable to initialize sysfs
mdadm: No arrays found in config file or automatically

> error: Error starting RAID array: Process reported exit code 1: mdadm: Unable to initialize sysfs
mdadm: No arrays found in config file or automatically

This clearly comes from mdadm, via a udisks dbus call (which is called in libblockdev).

I can't figure out the exact mdadm reproducer but I gathered strace output: mdadm-strace.log

Downstream report: https://bugzilla.redhat.com/show_bug.cgi?id=2385871

[jelly]

So note that we run rc0, it might be a kernel issue... 6.17.0-0.rc0.250730g4b290aae788e.3.fc43.x86_64

[jelly]

And it should be mdadm --assemble --scan --run --uuid=f63dc7c1:37a27c6f:bdda1af which fails

[root@fedora-rawhide-127-0-0-2-2201 ~]# mdadm --assemble --scan --run --uuid=982a9d5f:688f94f5:1e81ab1d:339c0cfb
mdadm: Unable to initialize sysfs
mdadm: No arrays found in config file or automatically

strace'd

openat(AT_FDCWD, "/dev/loop0", O_RDONLY|O_EXCL|O_DIRECT) = 5
ioctl(5, BLKSSZGET, [512])              = 0
fstat(5, {st_mode=S_IFBLK|0660, st_rdev=makedev(0x7, 0), ...}) = 0
ioctl(5, BLKGETSIZE64, [49999872])      = 0
lseek(5, 4096, SEEK_SET)                = 4096
read(5, "\374N+\251\1\0\0\0\0\0\0\0\0\0\0\0\230*\235_h\217\224\365\36\201\253\0353\234\f\373"..., 4096) = 4096
lseek(5, 0, SEEK_CUR)                   = 8192
close(5)                                = 0
fstat(4, {st_mode=S_IFBLK|0600, st_rdev=makedev(0x9, 0x7f), ...}) = 0
readlink("/sys/dev/block/9:127", 0x7ffe4f46ce90, 199) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/sys/block/md127/md", 0x7ffe4f46d010, 0) = -1 ENOENT (No such file or directory)
write(2, "mdadm: Unable to initialize sysf"..., 34mdadm: Unable to initialize sysfs

[jelly]

Reported by Yu as https://bugzilla.redhat.com/show_bug.cgi?id=2385871

[martinpitt]

Nice! So needs a naughty. Let's move this to bots to use as knownissue.

[martinpitt]

I sent PR #8070 to add a naughty pattern. Taking off the pilot board.