From 142b942a75cb10ede1b42bf85368d41449ab4e3b Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Mon, 6 Jul 2015 15:51:20 +0200 Subject: [PATCH] rhashtable: fix for resize events during table walk 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 Acked-by: Herbert Xu Signed-off-by: David S. Miller --- lib/rhashtable.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/lib/rhashtable.c b/lib/rhashtable.c index a60a6d335a91..cc0c69710dcf 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -610,6 +610,8 @@ void *rhashtable_walk_next(struct rhashtable_iter *iter) iter->skip = 0; } + iter->p = NULL; + /* Ensure we see any new tables. */ smp_rmb(); @@ -620,8 +622,6 @@ void *rhashtable_walk_next(struct rhashtable_iter *iter) return ERR_PTR(-EAGAIN); } - iter->p = NULL; - return NULL; } EXPORT_SYMBOL_GPL(rhashtable_walk_next);