ifnet: Defer detaching address family dependent data
Needs ReviewPublic
Actions

Authored by zlei on Fri, Mar 21, 3:12 PM.

Details

Reviewers

glebius
markj

Group Reviewers

network

Summary

While diagnosing PR 279653 and PR 285129, I observed that thread may
write to freed memory but the system do not crash. This hides the real
problem. A clear NULL pointer derefence is much better than writing to
freed memory.

PR: 279653
PR: 285129
MFC after: 2 weeks

Diff Detail

Repository

rG FreeBSD src repository

Lint

Lint Skipped

Unit

Tests Skipped

Event Timeline

zlei created this revision.Fri, Mar 21, 3:12 PM

Herald added subscribers: melifaro, ae, imp. · View Herald TranscriptFri, Mar 21, 3:12 PM

zlei requested review of this revision.Fri, Mar 21, 3:12 PM

zlei mentioned this in D49359: ifnet: Fix the teardown process of an interface.

franco_opnsense.org added inline comments.Fri, Mar 21, 4:37 PM

sys/net/if.c
1022	according to the debug core I have both if_afdata_initialized and all of if_afdata was zeroed, see https://reviews.freebsd.org/D49212#1122671

zlei added inline comments.Fri, Mar 21, 5:44 PM

sys/net/if.c
1022	according to the debug core I have both if_afdata_initialized and all of if_afdata was zeroed, see https://reviews.freebsd.org/D49212#1122671 It is also possible the writes from detaching thread is not global visible to other threads without proper sync. Then other threads may see stall data. @markj Can the crash dump shows the cache status of different cores ?