Re: port-amd64/56987 (Certain usb devices can no longer be mounted on -current)

[Taylor R Campbell <riastradh%NetBSD.org@localhost>]

> Date: Mon, 5 Jun 2023 20:41:51 -0400 (EDT)
> From: mlh%goathill.org@localhost (MLH)
> 
> Any advice on looking into fixing the usb device mounting issues
> that were broken with the usb changes last year? And yes, the usb
> subsystem is much more stable with those changes, but I really
> would like to finish things.

The best thing to do is to bisect to find exactly what change broke
it.  A lot of things changed between 9.99.93 and 9.99.94 over the
course of four months.

On any reasonably POSIXish system (doesn't have to be your NetBSD
machine), you can do this:

$ git clone https://github.com/NetBSD/src
$ cd src
$ ./build.sh -O ../obj -T ../tools -U -u -m amd64 -j4 tools
$ git bisect start
$ git bisect bad HEAD
$ git bisect good 8abbca48b237c9edc3ffb387e9074ddcff8b645d

And then, at each step, do

$ ./build.sh -O ../obj -T ../tools -U -u -m amd64 -j4 kernel=GENERIC

and try the kernel at ../obj/sys/arch/amd64/compile/GENERIC/netbsd.

- If it works, run `git bisect good'.
- If it fails the same way, `git bisect bad'.
- If it fails to build, or crashes in some other way, tun `git bisect
  skip'.

And keep going until it points you to a particular commit.

(f6d3947777a575d460fc1be6c52252513ecfba93 is the commit that bumped
the version to 9.99.92.  This range is a little larger than needed,
but that's fine -- bisection is logarithmic, so checking everything
from 9.99.92 to now vs checking everything from 9.99.93 to 9.99.94
will probably only add a couple more iterations.)


Another thing that might help, in case there is a thread that is just
wedged somewhere, is to run:

# crash
crash> ps
crash> ps/w

And, if you're using a kernel from the last week:

crash> show all tstiles

And then share the output.  But I suspect it's not a wedged thread;
that would probably manifest in other ways.


It might also help to share dmesg from the working 9.99.93 kernel so
we can look at all of it side-by-side with the broken 9.99.94 kernel
or whatever.