Re: kernel panic while copying files

From: Gary Jennejohn <>
Date: Tue, 08 Jun 2021 14:41:58 UTC
On Tue, 8 Jun 2021 06:48:19 -0600
Warner Losh <> wrote:

> Sorry to reply to myself... had a thought as my brain rested while making
> tea...
> I think we may need to consider reverting (or at least not yet enabling)
> the uma stuff.

I tested and enabled the UMA CCB stuff immediately after trasz had
committed it.  I was able to copy files panic-free over USB until
recently AFAICR.

I also have had the set since
then and have never seen a problem there.  Only with USB.

I'll try booting a new kernel with the uma_ccb sysctl's set to 0
and see what happens.

BTW I now have a kernel compiled with -O0 ready to test.

[snip lots of extraneous stuff]

Gary Jennejohn