In rte_hash_iterate, the reader lock did not protect the
while loop which checks empty entry. This created a race
condition that the entry may become empty when enters
the lock, then a wrong key data value would be read out.

This commit extends the protected region.

Fixes: f2e3001b53ec ("hash: support read/write concurrency")
Cc: sta...@dpdk.org

Signed-off-by: Yipeng Wang <yipeng1.w...@intel.com>
Reported-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
---
 lib/librte_hash/rte_cuckoo_hash.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/librte_hash/rte_cuckoo_hash.c 
b/lib/librte_hash/rte_cuckoo_hash.c
index f7b86c8..eba13e9 100644
--- a/lib/librte_hash/rte_cuckoo_hash.c
+++ b/lib/librte_hash/rte_cuckoo_hash.c
@@ -1317,16 +1317,19 @@ rte_hash_iterate(const struct rte_hash *h, const void 
**key, void **data, uint32
        bucket_idx = *next / RTE_HASH_BUCKET_ENTRIES;
        idx = *next % RTE_HASH_BUCKET_ENTRIES;
 
+       __hash_rw_reader_lock(h);
        /* If current position is empty, go to the next one */
        while (h->buckets[bucket_idx].key_idx[idx] == EMPTY_SLOT) {
                (*next)++;
                /* End of table */
-               if (*next == total_entries)
+               if (*next == total_entries) {
+                       __hash_rw_reader_unlock(h);
                        return -ENOENT;
+               }
                bucket_idx = *next / RTE_HASH_BUCKET_ENTRIES;
                idx = *next % RTE_HASH_BUCKET_ENTRIES;
        }
-       __hash_rw_reader_lock(h);
+
        /* Get position of entry in key table */
        position = h->buckets[bucket_idx].key_idx[idx];
        next_key = (struct rte_hash_key *) ((char *)h->key_store +
-- 
2.7.4

Reply via email to