bug#74607: Evaluations of the ‘guix’ jobset failing on ci.guix

["Ludovic Courtès" <ludo@gnu.org>]

Evaluations of the ‘guix’ jobset have been failing on ci.guix when
computing the derivation for aarch64-linux.

Example from <https://ci.guix.gnu.org/eval/1856888/log/raw> (commit
369d2698b0bfc3726f8e6d232d43d0dda832225f):

--8<---------------cut here---------------start------------->8---
[ 28/ 30] compiling...	 86.7% of 15 files
[ 29/ 30] compiling...	 93.3% of 15 files
[ 30/ 30] compiling...	100.0% of 15 files
retrieving 1 store item from '141.80.167.181'...
importing file or directory '/gnu/store/cfpvmda7klp0f5ywxkl2nagghkz7zvbi-guix-cli-core'...
found valid signature for '/gnu/store/cfpvmda7klp0f5ywxkl2nagghkz7zvbi-guix-cli-core'

.[Kregistering 1 items  ??????????????????????????????????????????????????????????
.[Kregistering 1 items
done with offloaded '/gnu/store/5nkhf15ma6c4lfindr4xp56ldcqvy4qi-guix-cli-core.drv'
building path(s) `/gnu/store/wbhwdxg03n4cc01wm6aib5w0lw3p0rm4-guix-cli-core-modules'
Registering builds for evaluation 1856888.
Registering builds for evaluation 1856888.
Registering builds for evaluation 1856888.
In thread:
uncaught throw to %exception: (#<&inferior-exception arguments: (%exception #<inferior-object #<&message message: "You found a bug: the program '/gnu/store/v48zc2lbx5c5726wzljp29rnrw1851li-compute-guix-derivation'\nfailed to compute the derivation for Guix (version: \"369d2698b0bfc3726f8e6d232d43d0dda832225f\"; system: \"aarch64-linux\";\nhost version: \"369d2698b0bfc3726f8e6d232d43d0dda832225f\"; pull-version: 1).\nPlease report the COMPLETE output above by email to <bug-guix@gnu.org>.\n">>) inferior: #<inferior pipe (0 1 1) 7ff1a5114f40> stack: ((#f ("ice-9/boot-9.scm" 1779 13)) (raise-exception ("ice-9/boot-9.scm" 1682 16)) (raise-exception ("ice-9/boot-9.scm" 1684 16)) (#f ("ice-9/eval.scm" 190 27)) (run-with-store ("guix/store.scm" 2209 25)) (#f ("gnu/ci.scm" 241 16)) (map1 ("srfi/srfi-1.scm" 585 17)) (map1 ("srfi/srfi-1.scm" 585 17)) (append-map ("srfi/srfi-1.scm" 672 15)) (cuirass-jobs ("gnu/ci.scm" 516 4)) (#f ("ice-9/eval.scm" 158 9)) (with-exception-handler ("ice-9/boot-9.scm" 1751 10)) (call-with-prompt ("ice-9/boot-9.scm" 723 2)) (#f (#f #f #f)) (#f ("guix/repl.scm" 98 21)) (with-exception-handler ("ice-9/boot-9.scm" 1751 10)) (with-exception-handler ("ice-9/boot-9.scm" 1746 15)) (#f ("guix/repl.scm" 125 7)))>)
--8<---------------cut here---------------end--------------->8---

The first failure was apparently <https://ci.guix.gnu.org/eval/1853560>
(commit 0376420e8785204effa56cbbdd91ad425fbdff18); previous one was
<https://ci.guix.gnu.org/eval/1852892> (commit
cd26d76fedb7ab13ad91bd5dcfce119892b8e62e).

Somehow the corresponding ‘cuirass evaluate’ process hangs, using one
(out of 8) concurrent evaluation slots of ‘cuirass register’, and thus
delaying other evaluations.

Ludo’.