On 12/3/14, 12:24 AM, Warner Losh wrote:
On Dec 1, 2014, at 10:08 PM, Julian Elischer <jul...@freebsd.org> wrote:

On 12/1/14, 11:39 PM, John Baldwin wrote:
On Friday, November 28, 2014 11:08:35 PM Julian Elischer wrote:
Do we need to compile all modules with witness definitions when
linking with a kernel compiled with witness?
This was true at one stage but I remember some work was done to make
them compatible.
You should not need this.  modules always call functions in the kernel for
lock operations and this functions are what invoke WITNESS.

that's what I thought but empirical evidence disagrees.
I'll try some more cases.
I swap back and forth all the time between the two. Kernel modules don’t
change when you compile them with WITNESS or without.

Warner

it's a 10.0 based system.

the zfs kernel module grew a reference to witness_restore and witness_save when it was compiled with witness in opt_global.h. I certainly wouldn't load with a standard kernel. it may have been somethign funny with the zfs compat layer stuff, and I'm pretty sure people don't use zfs as a module much, but it was definitely there. note: it'd probably work the other way around.. a non-witness module would probably load on a witness kernel.. none of the other kernel modules had that extra reference so I think it's specific to zfs. Maybe to the way it was compiled.. the sources are pretty standard but the makefiles are a bit hacked..



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