I've had no luck getting responses from any drm-kmod folks despite pinging on reviews. I think I will just go ahead and push this to main now and reply to the commit saying it breaks drm-kmod and letting the drm-kmod folks sort it out.

In D54148#1236974, @kp wrote:

What's this based on? It doesn't seem to want to apply to FreeBSD main (f9500e75791cf793904c80ca4a52433afd585a23).

I manually applied it to my cheri tree, and that does indeed work.

Hopefully rman routines are not used in any critical paths (attach/detach handlers should be a relatively rare path compared to, say, an interrupt handler)

After reverting my earlier fix (which I don't intend to MFC and by which I was distracted by the "optimization" of reusing the existing buffer), this fixes pfctl for me on CHERI. In effect, it makes Igor's original commit just add the missing 'nw->size = new_size'. I think that probably explains both of the issues Igor noted in the original commit log. The buffer overflows were caused by nw->offset exceeding nw->size and eventually the realloc'd buffer was simply too small as it was only 'nw->size + <size of current object needed>' which could easily be smaller than 'nw->offset' once you've appended a few things larger than the initial buffer size.

Hmmm, I wonder if 0 is the right thing vs something like 0xdeadc0de. We have a few explicit IVAR handlers that intentionally return a default value (e.g. acpi_get_handle()) and those do tend to be zero (and in those cases we don't KASSERT). I have a patch in a branch to add a new one like that for ThunderBolt PCI bridges even. 0 is probably fine as a default, but @imp might also have an opinion.

In D54051#1234938, @olce wrote:

There is an occurrence of "swapper" in sys/vm/vnode_pager.c that seems to also point to the swapper process.

Use ruxreset

Add to OptionalObsoleteFiles.inc

FYI, submitter of the bug report tried this out and it fixed their issue.

More const

Use ?=

Trim #if 0'd code

Use void *

Well, this isn't a generated stub so using void * could be ok, OTOH, it is now always passed something like wcred->cr_label in which case it is typed (though user_setcred intentionally discards that type) and it might be nice to keep what type checking you do get there (so that for internal APIs a compat user pointer is always treated as the native user pointer). Most places where we deal with user pointers though they are just one type and not polymorphic as in this case. Globally changing all user pointers would definitely be a net negative, but using void * here is probably fine.