Re: Getting /usr/src to match specific git hash?

On Sun, Jan 24, 2021 at 3:22 PM Warner Losh <imp_at_bsdimp.com> wrote:

>
>
> On Sun, Jan 24, 2021, 12:14 PM Steve Kargl <
> sgk_at_troutmask.apl.washington.edu> wrote:
>
>> On Sun, Jan 24, 2021 at 09:00:45AM -0700, Warner Losh wrote:
>> > On Sun, Jan 24, 2021, 6:05 AM Jeffrey Bouquet <
>> jbtakk_at_iherebuywisely.com>
>> > wrote:
>> >
>> > >
>> > >
>> > > On Sat, 23 Jan 2021 20:14:03 -0800, Steve Kargl <
>> > > sgk_at_troutmask.apl.washington.edu> wrote:
>> > >
>> > > > On Sun, Jan 24, 2021 at 01:08:05PM +0900, Yasuhiro Kimura wrote:
>> > > > > From: Steve Kargl <sgk_at_troutmask.apl.washington.edu>
>> > > > > Subject: Getting /usr/src to match specific git hash?
>> > > > > Date: Sat, 23 Jan 2021 19:58:52 -0800
>> > > > >
>> > > > > > Suppose one has an empty /usr/src.
>> > > > > >
>> > > > > > Suppose further that one had to re-install a 32-bit
>> > > > > > i386-*-freebsd with the 24 Dec 2020 image available
>> > > > > > from freebsd.org.
>> > > > > >
>> > > > > > uname -a for the booted kernel shows
>> > > > > >
>> > > > > > % uname -a
>> > > > > > FreeBSD mobile 13.0-CURRENT FreeBSD 13.0-CURRENT #0 \
>> > > > > > 3cc0c0d66a0-c255241(main)-dirty: Thu Dec 24 05:43:23 UTC 2020 \
>> > > > > > root_at_releng1.nyi.freebsd.org:
>> /usr/obj/usr/src/i386.i386/sys/GENERIC
>> > > i386
>> > > > > >
>> > > > > > How does one use git to pull the exact sources that match
>> > > > > > this specifc kernel?
>> > > > >
>> > > > > cd /usr
>> > > > > git clone https://git.freebsd.org/src.git
>> > > > > cd src
>> > > > > git checkout 3cc0c0d66a0
>> > > > >
>> > > >
>> > > > Thank you.
>> > > >
>> > >
>> > > Can this be put in /usr/src/UPDATING with an explanation of precisely
>> how
>> > > each
>> > > of the git commands populates or repopulated the directories in
>> /usr???
>> > >
>> >
>> > It is in the mini primer I wrote, along with how to bisect and other
>> useful
>> > things. This will migrate into the handbook once the doc tree converts
>> to
>> > asciidoc (happening this weekend).
>> >
>> > https://github.com/bsdimp/freebsd-git-docs/blob/main/mini-primer.md
>> >
>>
>> Any advice on how to jump, say, 4 days ahead of the current
>> date of the src/ tree?  That is, I have src/ that should
>> correspond to 24 Dec 2020.  How do I jump to 28 Dec 2020?
>>
>
> You could use git bisect, but as you say, the laundry list is extensive.
>
> Git doesn't offer checkout by date, alas. So here's some tools to help you
> out.
>
> First, let's get a count of how many commits behind main you are at the
> moment. Use 'git log --oneline --first-parent HEAD..main | wc' to get a
> count of the number of commits between what you have checked out and the
> tip of current. My count is 994, but I just updated, so your count will
> differ and that's OK.The --first-parent in the git log above is critical,
> since otherwise a number of commits from vendor merges in the vendor
> branches will appear in git log's output, throwing the count off).
>
> Now, this is 1 month worth of -current. 4 days in the month is about 13%.
> However, let's keep things simple and step forward 100 commits at a time
> (which is 10% of 1000). The precise numbers don't matter, but it works out
> well in this case.
>
> So, your commit is:
> % git log -1 3cc0c0d66a0
> Author: Li-Wen Hsu <lwhsu_at_FreeBSD.org>
> Date:   Sun Dec 20 02:59:44 2020 +0000
>
>     Mark the repository as being converted to Git.
>
> which is the last subversion commit. It's also head~994, you can do a 'git
> log -1 main~900' to verify that. So, let's move forward 94 commits. This
> would be:
>

The 'main~900' should be 'main~994' here since you are verifying main~944.
Also 'head~994' was a typo for 'main~994'. Sorry for any confusion these
mistakes caused.


> % git log main~900
> commit 8d405efd73d3991fe1647f91a2b7c9989dd5f18f
> Author: Ulrich Sp<C3><B6>rlein <uqs_at_FreeBSD.org>
> Date:   Wed Dec 23 22:29:34 2020 +0100
>
>     Fix newvers.sh to no longer print an outdated SVN rev
>
> which is 3 days newer and may be a good place to start:
>
> % git checkout main~900
>
> and that will move you forward 94 commits. Do it again with main~800, etc
> to find a spot that's good for you. Not as convenient as giving dates, but
> once you have a count of the number of commits between where you are and
> head, you can use that number to decide how far forward to go.
>
> You can adjust this as needed. If you don't do a git pull during this
> process (and you likely shouldn't) these numbers will be stable, and a lot
> easier to work with than hashes. I've found I like to move N commits rather
> than N days.
>
> Hope this is helpful. Sadly I found no way to say HEAD+50 commits directly
> in git, but maybe one of the more knowledgeable folks on this list can give
> a better hint there.
>
> Warner
>
>
> My past week experience with top-of-tree suggests doing
>> a bisection would be frought with peril.  My laptop runs
>> well with 24 Dec 2020 kernel/world.  Getting to top-of-tree,
>> one has to deal with
>> (1) infinite recursion in wpa_supplicant,
>> (2) possible locking issue in UFS (30 second system freezes),
>> (3) memory alignment messages from the kernel,
>> (4) processes being killed with out-of-swapspace messages
>>     even though I have 4 GB of untouched swap space.  Might
>>     be associated with (3).
>> (5) graphic console mess
>> (6) pilot-error of using -march=core2, which matches the
>>     processor in the laptop, to build kernel/world but
>>     manifests a llvm bug
>>
>> I would like to creep up on the issues.
>>
>> --
>> Steve
>>
>