Date: Mon, 4 Apr 2011 07:45:08 +0000 (UTC) From: Gleb Smirnoff <glebius@FreeBSD.org> To: cvs-src-old@freebsd.org Subject: cvs commit: src/sys/net if.c Message-ID: <201104040745.p347jNSC062047@repoman.freebsd.org>
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glebius 2011-04-04 07:45:08 UTC
FreeBSD src repository
Modified files:
sys/net if.c
Log:
SVN rev 220317 on 2011-04-04 07:45:08Z by glebius
When removing ifnets, we should first remove the reference to ifnet
from the interface index, then decrease refcount, not vice versa.
Otherwise there is a race (reproducible) when if_free_internal()
contests on IFNET_WLOCK(), and we got a zero-refed ifnet in the
index for a long time. It may be picked by some other thread,
that runs ifnet_byindex_ref(), who takes the ifnet from index,
and bumps refcount. When reader drops the lock, if_free_internal()
proceeds with free. Then reader tries to free it a second time.
Revision Changes Path
1.399 +10 -9 src/sys/net/if.c
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