Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754734AbbGFMK2 (ORCPT ); Mon, 6 Jul 2015 08:10:28 -0400 Received: from orbit.nwl.cc ([176.31.251.142]:41621 "EHLO mail.nwl.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751427AbbGFMK0 (ORCPT ); Mon, 6 Jul 2015 08:10:26 -0400 X-Greylist: delayed 521 seconds by postgrey-1.27 at vger.kernel.org; Mon, 06 Jul 2015 08:10:25 EDT From: Phil Sutter To: Thomas Graf Cc: sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, davem@davemloft.net, herbert@gondor.apana.org.au, daniel@iogearbox.net, geert@linux-m68k.org, mroos@linux.ee Subject: [PATCH] rhashtable: fix for resize events during table walk Date: Mon, 6 Jul 2015 14:01:42 +0200 Message-Id: <1436184102-19175-1-git-send-email-phil@nwl.cc> X-Mailer: git-send-email 2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1722 Lines: 53 If rhashtable_walk_next detects a resize operation in progress, it jumps to the new table and continues walking that one. But it misses to drop the reference to it's current item, leading it to continue traversing the new table's bucket in which the current item is sorted into, and after reaching that bucket's end continues traversing the new table's second bucket instead of the first one, thereby potentially missing items. This fixes the rhashtable runtime test for me. Bug probably introduced by Herbert Xu's patch eddee5ba ("rhashtable: Fix walker behaviour during rehash") although not explicitly tested. Fixes: eddee5ba ("rhashtable: Fix walker behaviour during rehash") Signed-off-by: Phil Sutter --- lib/rhashtable.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/lib/rhashtable.c b/lib/rhashtable.c index a60a6d3..e36b94b 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -585,6 +585,7 @@ void *rhashtable_walk_next(struct rhashtable_iter *iter) struct bucket_table *tbl = iter->walker->tbl; struct rhashtable *ht = iter->ht; struct rhash_head *p = iter->p; + void *rc = NULL; if (p) { p = rht_dereference_bucket_rcu(p->next, tbl, iter->slot); @@ -617,12 +618,12 @@ next: if (iter->walker->tbl) { iter->slot = 0; iter->skip = 0; - return ERR_PTR(-EAGAIN); + rc = ERR_PTR(-EAGAIN); } iter->p = NULL; - return NULL; + return rc; } EXPORT_SYMBOL_GPL(rhashtable_walk_next); -- 2.1.2 -- 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/