Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755350AbbLQIsX (ORCPT ); Thu, 17 Dec 2015 03:48:23 -0500 Received: from helcar.hengli.com.au ([209.40.204.226]:56857 "EHLO helcar.hengli.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751501AbbLQIsV (ORCPT ); Thu, 17 Dec 2015 03:48:21 -0500 Date: Thu, 17 Dec 2015 16:48:09 +0800 From: Herbert Xu To: Xin Long Cc: Phil Sutter , davem , network dev , linux-kernel@vger.kernel.org, tgraf@suug.ch, fengguang.wu@intel.com, wfg@linux.intel.com, lkp@01.org Subject: Re: rhashtable: Prevent spurious EBUSY errors on insertion Message-ID: <20151217084809.GC9239@gondor.apana.org.au> References: <1448039840-11367-1-git-send-email-phil@nwl.cc> <20151130093755.GA8159@gondor.apana.org.au> <20151130101401.GA17712@orbit.nwl.cc> <20151130101859.GA8378@gondor.apana.org.au> <20151203124129.GA5505@gondor.apana.org.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1083 Lines: 32 On Thu, Dec 17, 2015 at 04:46:00PM +0800, Xin Long wrote: > > sorry for late test, but unfortunately, my case with rhashtalbe still > return EBUSY. > I added some debug code in rhashtable_insert_rehash(), and found: > *future_tbl is null* > > fail: > /* Do not fail the insert if someone else did a rehash. */ > if (likely(rcu_dereference_raw(tbl->future_tbl))) { > printk("future_tbl is there\n"); > return 0; > } else { > printk("future_tbl is null\n"); > } > > any idea why ? That's presumably because you got a genuine double rehash. Until you post your code we can't really help you. Cheers, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/