I do not like the teared completion of the linker file state in your patch, and that the inconsistent state is visible after kld_sx is dropped.

You might transpose the change, by counting modules and failed modules in the linker files instead. Then finalizing action in the linker_preload() may handle the remnants, detected by the counters being equal.

In D8200#170190, @kib wrote:

I do not like the teared completion of the linker file state in your patch, and that the inconsistent state is visible after kld_sx is dropped.

This is exactly the same in the runtime linker path. See linker_file_sysinit(), where kld_sx is dropped while sysinits run. Meanwhile the half-loaded kobj is visible.

(Note that this is a case where a linker file without LINKER_FILE_LINKED set would be visible to userspace — the case imagined but not proved in D8167.)

You might transpose the change, by counting modules and failed modules in the linker files instead. Then finalizing action in the linker_preload() may handle the remnants, detected by the counters being equal.

Modules may need to be visible in this half-loaded state for other preloaded linker files' SYSINITs to run. (We can't necessarily keep everything hidden until after preload_finish runs.)

Otherwise, that would be fine, but seems functionally identical. I don't see any reason to prefer that approach. Is there one? See for example the identical test in linker_load_file:

432                         modules = !TAILQ_EMPTY(&lf->modules);
433                         linker_file_register_sysctls(lf);
434                         linker_file_sysinit(lf);
435                         lf->flags |= LINKER_FILE_LINKED;
436
437                         /*
438                          * If all of the modules in this file failed
439                          * to load, unload the file and return an
440                          * error of ENOEXEC.
441                          */
442                         if (modules && TAILQ_EMPTY(&lf->modules)) {
443                                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
444                                 return (ENOEXEC);
445                         }

The LINKER_FILE_MODULES flag just takes the place of the boolean modules variable in linker_load_file for preloaded kobjs.