The MALLOC_MAKE_FAILURES kernel option could be used to inject failures
for malloc(9) allocations which use the M_NOWAIT flag.  This is an
expansion and enhancement.
 - Failures may now be injected for UMA zalloc instead of just malloc.
 - A fail(9) fail_point now controls injection instead of an ad hoc rate
   mechanism.
 - A whitelist and blacklist now allow specific malloc type and UMA zone
   names to be targeted or avoided.
 - Details about the last injection are now recorded to aid debugging.

This currently still lacks a manual page and the option is not yet
enabled in any kernel configurations.

Reviewers: markj, rwatson
Subscribers: glebius, jeff

Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D20714

On INVARIANTS kernels, UMA has a use-after-free detection mechanism.
This mechanism previously required that all of the ctor/dtor/uminit/fini
arguments to uma_zcreate() be NULL in order to function.  Now, it only
requires that uminit and fini be NULL; now, the trash ctor and dtor will
be called in addition to any supplied ctor or dtor.

Also do a little refactoring for readability of the resulting logic.

This enables use-after-free detection for more zones, and will allow for
simplification of some callers that worked around the previous
restriction (see kern_mbuf.c).

Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D20722

The igmp_ifsoftc allocation was done with M_NOWAIT, but it did not
handle failure.  It may have trapped immediately, or at detach time.
Actually, the allocation does not appear to need to be M_NOWAIT at all,
except for that it was being done under a mutex.  Instead, do an
M_WAITOK allocation outside the mutex.

Sponsored by:	Dell EMC Isilon

Reviewers: glebius
Subscribers: mmacy

Apply the igmp fix to mld6.

Sponsored by:	Dell EMC Isilon

Reviewers: glebius
Subscribers: mmacy

It looks like the call that requires the lock was introduced in r337866.

Sponsored by:	Dell EMC Isilon

Reviewers: glebius
Subscribers: mmacy, shurd

Apply a similar fix as for in6_mcast.c.

Sponsored by:	Dell EMC Isilon

Reviewers: glebius
Subscribers: mmacy, shurd

Sponsored by:	Dell EMC Isilon

Reviewers: ae
Subscribers: cem

Sponsored by:	Dell EMC Isilon

Reviewers: pjd
Subscribers: ae, cem, markj

If g_mirror_taste encountered an error at g_mirror_add_disk, it might
try to g_mirror_destroy the device with the G_MIRROR_DEVICE_FLAG_TASTING
flag still set.  This would wait on a worker to complete the destruction
with g_mirror_try_destroy, but that function bails out if the tasting
flag is set, resulting in a deadlock.  Clear the tasting flag before
trying to destroy the device.

Tested with:
sysctl debug.fail_point.mnowait="1%return"
kyua test -k /usr/tests/sys/geom/class/mirror/Kyuafile

Sponsored by:	Dell EMC Isilon

Reviewers: markj, pjd
Subscribers: ae, cem