Re: realtime-preempt patch-2.6.15-rt18 issues

Ingo Molnar
2006-03-06T13:25:54Z

* Rui Nuno Capela <rncbc@rncbc.org> wrote:

> Hi, Ingo,
>
> I think I would let you know that I'm still on 2.6.15-rt16, which
> works great for the most purposes, on all of my boxes.
>
> My problem is that the current/latest of the realtime-preempt patch,
> 2.6.15-rt18, has some showstoppers, at least for my day-to-day usage.
>
> First one, and I think this is a return of an old buglet. Its the one
> that occurs every time an usb-storage device is unplugged (e.g. a usb
> flash stick). Once that happens, the usb subsystem gets seriously
> crippled.
>
> Here goes a sample dmesg output of this occurrence (the complete listing
> is attached, as is the corresponding kernel .config).
>
> ...
> usb 2-1: USB disconnect, address 2
> slab error in kmem_cache_destroy(): cache `scsi_cmd_cache': Can't free all
> objects

hm, this implicates the SLAB code. I've uploaded -rt19, does it work any
better [there i've included a newer version of the rt-SLAB code]? If you
still get the same problem even under -rt19, do things improve if you
enable CONFIG_EMBEDDED and CONFIG_SLOB?

(-rt19 also has the tasklet/ALSA fix, and some other fixlets)

Ingo