From: Gabriel Oginski <gabrielx.oginski@intel.com>
Date: Fri, 21 Oct 2022 07:05:56 +0000 (+0000)
Subject: hash: add local variable
X-Git-Tag: v23.06-rc0~167
X-Git-Url: https://gerrit.fd.io/r/gitweb?a=commitdiff_plain;h=813c1bd257ddcc573422083bd66cc8b8ed79d5b2;p=vpp.git

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 <gabrielx.oginski@intel.com>
Change-Id: Iecf6b3ef9f308b61015c66277cc459a6d019c9c1
---

diff --git a/src/vppinfra/hash.h b/src/vppinfra/hash.h
index 968c7781c36..3c754c8e29f 100644
--- 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;
 }