Date: Mon, 12 Apr 2010 15:33:52 +0100 From: Rui Paulo <rpaulo@FreeBSD.org> To: Sam Leffler <sam@errno.com> Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org Subject: Re: svn commit: r206419 - head/sys/net80211 Message-ID: <256D847F-E64D-4802-8266-C2AC4DCDFF72@FreeBSD.org> In-Reply-To: <4BC250CF.30600@errno.com> References: <201004091206.o39C6JBo046371@svn.freebsd.org> <4BC250CF.30600@errno.com>
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On 11 Apr 2010, at 23:44, Sam Leffler wrote: > Rui Paulo wrote: >> Author: rpaulo >> Date: Fri Apr 9 12:06:19 2010 >> New Revision: 206419 >> URL: http://svn.freebsd.org/changeset/base/206419 >> Log: >> Use M_NOWAIT instead of M_WAITOK to avoid race conditions. >> =20 >=20 > Can you describe these race conditions (or at least one of them)? Some drivers call ratectl functions with locks held. I saw similar = allocations in the net80211 stack that used M_NOWAIT and printed an = error if the allocation failed, but didn't notify the caller (for = example ieee80211_node_table_init()). If I use M_WAITOK here I'll also get WITNESS warnings. Regards, -- Rui Paulo
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