hash: add local variable

The current implmentation of the hash table is not thread-safe. This design leads to a segfault when VPP handling a lot of tunnels for Wireguard, where one thread modify the hash table and other threads starting to lookup at the same time. The fix add a local variable to store how many bits are used by a user object. Type: fix Signed-off-by: Gabriel Oginski <[email protected]> Change-Id: Iecf6b3ef9f308b61015c66277cc459a6d019c9c1
FDio · Oct 25, 2022 · 813c1bd · 813c1bd
1 parent c9d916c
commit 813c1bd
Showing 1 changed file with 3 additions and 2 deletions.
diff --git a/src/vppinfra/hash.h b/src/vppinfra/hash.h
@@ -123,8 +123,9 @@ always_inline uword
 hash_is_user (void *v, uword i)
 {
   hash_t *h = hash_header (v);
-  uword i0 = i / BITS (h->is_user[0]);
-  uword i1 = i % BITS (h->is_user[0]);
+  uword bits = BITS (h->is_user[0]);
+  uword i0 = i / bits;
+  uword i1 = i % bits;
   return (h->is_user[i0] & ((uword) 1 << i1)) != 0;
 }