CVS commit: [netbsd-8] src/sys

["Soren Jacobsen" <snj%netbsd.org@localhost>]

Module Name:    src
Committed By:   snj
Date:           Fri Nov 17 20:24:05 UTC 2017

Modified Files:
        src/sys/net [netbsd-8]: if_llatbl.c if_llatbl.h
        src/sys/netinet [netbsd-8]: if_arp.c in.c
        src/sys/netinet6 [netbsd-8]: in6.c nd6.c

Log Message:
Pull up following revision(s) (requested by ozaki-r in ticket #353):
        sys/net/if_llatbl.c: 1.22
        sys/net/if_llatbl.h: 1.13
        sys/netinet/if_arp.c: 1.254
        sys/netinet/in.c: 1.208-1.209
        sys/netinet6/in6.c: 1.249-1.250
        sys/netinet6/nd6.c: 1.237
Remove redundant KASSERTMSG
The function is static, has just one caller and the caller does the same check.
--
Fix a deadlock between a route update and lltable
It happens because rtalloc1 is called from lltable with holding
IF_AFDATA_WLOCK.
If a route update is in action, rtalloc1 would wait for its completion with
holding IF_AFDATA_WLOCK. At the same moment, a softint (e.g., arpintr) may try
to take IF_AFDATA_WLOCK and get stuck on it. Unfortunately the stuck softint
prevents the route update from progressing because the route update calls
psref_target_destroy that needs the softint to complete.
A resource allocation graph of the senario looks like this:
    route update =(psref_target_destroy)=> softint => IF_AFDATA_WLOCK
    =(rt_update_wait)=> route update
Fix the deadlock by pulling rtalloc1 out of the lltable codes inside
IF_AFDATA_WLOCK.
Note that the deadlock happens only if NET_MPSAFE is enabled.


To generate a diff of this commit:
cvs rdiff -u -r1.18.6.1 -r1.18.6.2 src/sys/net/if_llatbl.c
cvs rdiff -u -r1.10.8.1 -r1.10.8.2 src/sys/net/if_llatbl.h
cvs rdiff -u -r1.250.2.2 -r1.250.2.3 src/sys/netinet/if_arp.c
cvs rdiff -u -r1.203.2.1 -r1.203.2.2 src/sys/netinet/in.c
cvs rdiff -u -r1.245.2.1 -r1.245.2.2 src/sys/netinet6/in6.c
cvs rdiff -u -r1.232.2.2 -r1.232.2.3 src/sys/netinet6/nd6.c

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