Module Name: src Committed By: ozaki-r Date: Fri Nov 10 07:24:28 UTC 2017
Modified Files: src/sys/net: if_llatbl.c if_llatbl.h src/sys/netinet: if_arp.c in.c src/sys/netinet6: in6.c nd6.c Log Message: 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 -r1.21 -r1.22 src/sys/net/if_llatbl.c cvs rdiff -u -r1.12 -r1.13 src/sys/net/if_llatbl.h cvs rdiff -u -r1.253 -r1.254 src/sys/netinet/if_arp.c cvs rdiff -u -r1.208 -r1.209 src/sys/netinet/in.c cvs rdiff -u -r1.249 -r1.250 src/sys/netinet6/in6.c cvs rdiff -u -r1.236 -r1.237 src/sys/netinet6/nd6.c Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files.