From 28134a53d624ae7e90fff8500b25b3add4d40b92 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Wed, 4 Feb 2015 07:33:22 +1100 Subject: [PATCH] rhashtable: Fix potential crash on destroy in rhashtable_shrink The current being_destroyed check in rhashtable_expand is not enough since if we start a shrinking process after freeing all elements in the table that's also going to crash. This patch adds a being_destroyed check to the deferred worker thread so that we bail out as soon as we take the lock. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- lib/rhashtable.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/lib/rhashtable.c b/lib/rhashtable.c index c41e21096373..904b419b72f5 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -487,6 +487,9 @@ static void rht_deferred_worker(struct work_struct *work) ht = container_of(work, struct rhashtable, run_work); mutex_lock(&ht->mutex); + if (ht->being_destroyed) + goto unlock; + tbl = rht_dereference(ht->tbl, ht); if (ht->p.grow_decision && ht->p.grow_decision(ht, tbl->size)) @@ -494,6 +497,7 @@ static void rht_deferred_worker(struct work_struct *work) else if (ht->p.shrink_decision && ht->p.shrink_decision(ht, tbl->size)) rhashtable_shrink(ht); +unlock: mutex_unlock(&ht->mutex); }