Date: Tue, 1 Sep 2015 11:58:16 -0700 From: Bryan Drewery <bdrewery@FreeBSD.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r287366 - head/sys/kern Message-ID: <55E5F548.50007@FreeBSD.org> In-Reply-To: <20150901182636.GO33167@funkthat.com> References: <201509011405.t81E5U0g025928@repo.freebsd.org> <20150901182636.GO33167@funkthat.com>
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On 9/1/15 11:26 AM, John-Mark Gurney wrote: > Konstantin Belousov wrote this message on Tue, Sep 01, 2015 at 14:05 +0000: >> Author: kib >> Date: Tue Sep 1 14:05:29 2015 >> New Revision: 287366 >> URL: https://svnweb.freebsd.org/changeset/base/287366 >> >> Log: >> Exit notification for EVFILT_PROC removes knote from the knlist. In >> particular, this invalidates the knote kn_link linkage, making the >> SLIST_FOREACH() loop accessing undefined values (e.g. trashed by >> QUEUE_MACRO_DEBUG). If the knote is freed by other thread when kq >> lock is released or when influx is cleared, e.g. by knote_scan() for >> kqueue owning the knote, the iteration step would access freed memory. >> >> Use SLIST_FOREACH_SAFE() to fix iteration. > > Please back this out immediately. > > I objected to this change, and you did not give me enough time to > properly address this change. > FWIW we've had the same change in the Isilon codebase for some time as well. -- Regards, Bryan Drewery
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