From: Willy Tarreau <w@1wt.eu>
Date: Wed, 11 Mar 2020 23:31:18 +0000 (+0100)
Subject: BUG/MEDIUM: random: align the state on 2*64 bits for ARM64
X-Git-Tag: v2.2-dev5~77
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1544c14c57f4e77df2a8dcc27bc7eaaba8bbb833;p=thirdparty%2Fhaproxy.git

BUG/MEDIUM: random: align the state on 2*64 bits for ARM64

x86_64 and ARM64 do support the double-word atomic CAS. However on
ARM it must be done only on aligned data. The random generator makes
use of such double-word atomic CAS when available but didn't enforce
alignment, which causes ARM64 to crash early in the startup since
commit 52bf839 ("BUG/MEDIUM: random: implement a thread-safe and
process-safe PRNG").

This commit just unconditionally aligns the arrays. It must be
backported to all branches where the commit above is backported
(likely till 2.0).
---

diff --git a/src/standard.c b/src/standard.c
index d16eebfea8..3afaf5a994 100644
--- a/src/standard.c
+++ b/src/standard.c
@@ -4530,7 +4530,7 @@ int varint_bytes(uint64_t v)
 
 
 /* Random number generator state, see below */
-static uint64_t ha_random_state[2];
+static uint64_t ha_random_state[2] ALIGNED(2*sizeof(uint64_t));
 
 /* This is a thread-safe implementation of xoroshiro128** described below:
  *     http://prng.di.unimi.it/
@@ -4542,8 +4542,8 @@ static uint64_t ha_random_state[2];
 uint64_t ha_random64()
 {
 	uint64_t result;
-	uint64_t old[2];
-	uint64_t new[2];
+	uint64_t old[2] ALIGNED(2*sizeof(uint64_t));
+	uint64_t new[2] ALIGNED(2*sizeof(uint64_t));
 
 #if defined(USE_THREAD) && (!defined(HA_CAS_IS_8B) || !defined(HA_HAVE_CAS_DW))
 	static HA_SPINLOCK_T rand_lock;