oh duh!

let me update

hrm...

when wcopen() is called, we call vt_open() which on the first open calls tem_init() which stashes the queue_t passed in from wcopen()

however wcclose() doesn't call vt_close() if the minor# is 0, which means that queue_t stashed by tem_init() is never cleared

and i'm not sure why we're explicitly skipping this for 0

or if maybe the tem_cleanup should move from vt_close() to vt_clean()

jbk: it occurs to me that the right way to use cpuid leaf 0x15 would be to run the HPET calibration as a sanity check, and if the leaf 0x15 frequency was within some tolerance of the measured value, use the cpuid frequency.

the intel sdm actually states that the TSC frequency is ecx * ebx/eax (if ecx and ebx are 'enumerated' -- not 0)

just there's a fair amount of intel chips where it's not

and of course nothing (AFAIK) for AMD

hrm.. on this tem issue me and tsoome have been looking at...

I'm going to go ahead and file a bug

but apparently we get _really_ lucky

at least most of the time

we're stashing a free'd queue_t, but apparently kmem_cache_alloc() is recycling it so that it ends up getting used for the right thing

at least most of the time

so it mostly works by accident

I would have thought DEBUG kernels would catch that.

or are we not double-freeing it?

well we free it, kmem_cache_alloc() appears to then recycle it so it's once again valid

and most of the time it gets reused for the same thing as it originally was

so by the time you access it again, it's valid

assuming of course it's been recycled

for that use

and not some other stream

ah, dumb luck. is it a queue_t-specific cache?

yeah.. there's a kmem cache for queue_ts

i don't know if there's a way offhand to maybe make kmem use an alternate reuse strategy

the magazine structure means you generally have very fast LIFO reuse

on a per-cpu basis

very cache friendly

ok.. now to grab lunch :)

i guess if I really wanted to, I could try to catch allocq() reusing it, but i think capturing where it's getting saved, and then later passed to freeq(), then later back and all valid looking is I hope enough