Re: [REGRESSION] 6.7.1: md: raid5 hang and unresponsive system; successfully bisected

[Dan Moulding <dan@danm.net>]

Some additional new information: I realized after filing this report
that on the mainline there is a second commit, part of a pair, that
was supposed to go with commit 0de40f76d567. That second commit
upstream is d6e035aad6c0 ("md: bypass block throttle for superblock
update"). That commit probably also was supposed to have been
backported to stable along with the first, but was not, since it
provides what is supposed to be a replacement for the fix that has
been reverted.

So I rebuilt my kernel with the missed commit also backported instead
of just reverting the first commit (i.e. I have now built 6.7.1 with
just commit d6e035aad6c0 on top). Unfortunately, I can still reproduce
the hang after applying this second commit. So it looks
like even with that fix applied the regression is still present.

Coincidentally, I see it seems this second commit was picked up for
inclusion in 6.7.2 just today. I think that needs to NOT be
done. Instead the stable series should probably revert 0de40f76d567
until the regression is successfully dealt with on master. Probably no
further changes related to this patch series should be backported
until then.

Cheers,

-- Dan