CVS commit: src/sys

["Ryota Ozaki" <ozaki-r%netbsd.org@localhost>]

Module Name:    src
Committed By:   ozaki-r
Date:           Tue Jan 16 08:13:47 UTC 2018

Modified Files:
        src/sys/netinet: if_arp.c
        src/sys/netinet6: nd6_nbr.c

Log Message:
Make DAD destructions (MP-)safe with callout_stop

arp_dad_stoptimer and nd6_dad_stoptimer can be called with or without
softnet_lock held and unfortunately we have no easy way to statically know which.
So it is hard to use callout_halt there.

To address the situation, we use callout_stop to make the code safe. The new
approach copes with the issue by delegating the destruction of a callout to
callout itself, which allows us to not wait the callout to finish. This can be
done thanks to that DAD objects are separated from other data such as ifa.

The approach is suggested by riastradh@
Proposed on tech-kern@ and tech-net@


To generate a diff of this commit:
cvs rdiff -u -r1.255 -r1.256 src/sys/netinet/if_arp.c
cvs rdiff -u -r1.143 -r1.144 src/sys/netinet6/nd6_nbr.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.