From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: WARNING: at mm/slub.c:3357, kernel BUG at mm/slub.c:3413 Date: Mon, 21 Nov 2011 19:39:03 +0100 Message-ID: <1321900743.10470.31.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> References: <20111121080554.GB1625@x4.trippels.de> <20111121082445.GD1625@x4.trippels.de> <1321866988.2552.10.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <20111121131531.GA1679@x4.trippels.de> <1321884966.10470.2.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <20111121153621.GA1678@x4.trippels.de> <1321890510.10470.11.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <20111121161036.GA1679@x4.trippels.de> <1321894353.10470.19.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <1321895706.10470.21.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <20111121173556.GA1673@x4.trippels.de> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Cc: "Alex,Shi" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , Christoph Lameter , Pekka Enberg , Matt Mackall , "netdev@vger.kernel.org" , Tejun Heo To: Markus Trippelsdorf , Andrew Bresticker Return-path: In-Reply-To: <20111121173556.GA1673@x4.trippels.de> Sender: owner-linux-mm@kvack.org List-Id: netdev.vger.kernel.org Le lundi 21 novembre 2011 =C3=A0 18:35 +0100, Markus Trippelsdorf a =C3=A9= crit : > New one: ... I was just wondering if you were using CONFIG_CGROUPS=3Dy, and if yes, if you could try to disable it. css_get_next() looks very buggy, the read_lock()/read_unlock() protects nothing at all, RCU rules are not respected. commit c1e2ee2dc43657 (memcg: replace ss->id_lock with a rwlock) missed the point of doing a true RCU conversion to get even better results, and fact that previous code was buggy as well. [ After rcu lookup, we must get a stable reference, then recheck the key , or else we can manipulate something that was queued for deletion.] An example of a correct RCU conversion was done in commit 8af088710d1 (posix-timers: RCU conversion) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter= .ca/ Don't email: email@kvack.org