svn commit: r364310 - in head/sys: kern vm

[Mark Johnston]

On Tue, Aug 18, 2020 at 01:03:25AM +0300, Andriy Gapon wrote:
> On 17/08/2020 18:37, Gleb Smirnoff wrote:
> > Author: glebius
> > Date: Mon Aug 17 15:37:08 2020
> > New Revision: 364310
> > URL: https://svnweb.freebsd.org/changeset/base/364310
> > 
> > Log:
> >   With INVARIANTS panic immediately if M_WAITOK is requested in a
> >   non-sleepable context.  Previously only _sleep() would panic.
> >   This will catch misuse of M_WAITOK at development stage rather
> >   than at stress load stage.
> >   
> >   Reviewed by:	markj
> >   Differential Revision:	https://reviews.freebsd.org/D26027
> 
> I think that there is going to be a lot of fallout from this.
> Will you handle it?
> A warning from WITNESS is one thing, a panic is another.

Indeed, based on a few reports from freebsd-current I reverted the
commit.  It seems there are a number of places in CAM that will require
modification, particularly in async event handling.  Note that CAM doneq
threads execute handlers with TD_NO_SLEEPING.