From 1528f231b559670445cfc427937174535981917d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Petr=20Men=C5=A1=C3=ADk?= <pemensik@redhat.com>
Date: Fri, 18 Sep 2020 14:46:02 +0200
Subject: [PATCH] Fix isc_atomic_xadd symbol missing
Squashed commit of the following:
commit d8afe85342f05d8fec8ee0255451568e936b7eb2
Author: Mark Andrews <marka@isc.org>
Date: Mon Sep 7 16:12:31 2020 +1000
Update 'init_count' atomically to silence tsan errors.
(cherry picked from commit 90185b225f4c7acde2fbb04697d857fe496725a2)
commit f166c7fb7cc262a688ed511e40c9b0d551d5992d
Author: Mark Andrews <marka@isc.org>
Date: Thu Sep 3 12:53:53 2020 +1000
The node lock was released too early.
NEGATIVE needs to be call with the node lock held.
WARNING: ThreadSanitizer: data race
Write of size 2 at 0x000000000001 by thread T1 (mutexes: write M1):
#0 mark_stale_header lib/dns/rbtdb.c:1802:21
#1 add32 lib/dns/rbtdb.c:6559:5
#2 addrdataset lib/dns/rbtdb.c:6975:12
#3 dns_db_addrdataset lib/dns/db.c:783:10
#4 cache_name lib/dns/resolver.c:5829:13
#5 cache_message lib/dns/resolver.c:5926:14
#6 resquery_response lib/dns/resolver.c:8618:12
#7 dispatch lib/isc/task.c:1157:7
#8 run lib/isc/task.c:1331:2
Previous read of size 2 at 0x000000000001 by thread T2:
#0 cache_findrdataset lib/dns/rbtdb.c:5932:6
#1 dns_db_findrdataset lib/dns/db.c:739:10
#2 query_addadditional2 bin/named/query.c:2196:11
#3 additionaldata_ns lib/dns/./rdata/generic/ns_2.c:198:10
#4 dns_rdata_additionaldata lib/dns/rdata.c:1246:2
#5 dns_rdataset_additionaldata lib/dns/rdataset.c:629:12
#6 query_addrdataset bin/named/query.c:2411:8
#7 query_addrrset bin/named/query.c:2802:2
#8 query_addbestns bin/named/query.c:3501:2
#9 query_find bin/named/query.c:9165:4
#10 query_resume bin/named/query.c:4164:12
#11 dispatch lib/isc/task.c:1157:7
#12 run lib/isc/task.c:1331:2
(cherry picked from commit a1dcb73f677969d99df3ccff2acf4737e18a72b1)
commit 591a80fa95b8f3f3e716c45ceb9c5e4ccfa551c8
Author: Mark Andrews <marka@isc.org>
Date: Mon Aug 24 17:34:58 2020 +1000
increment header->count atomically
(cherry picked from commit 121837aa75ced489e28f8ce1dd20315487d199fa)
---
lib/dns/rbtdb.c | 43 +++++++++++++++++++++++++++++++++++--------
1 file changed, 35 insertions(+), 8 deletions(-)
diff --git a/lib/dns/rbtdb.c b/lib/dns/rbtdb.c
index 88c39bf714..31ced8e73a 100644
--- a/lib/dns/rbtdb.c
+++ b/lib/dns/rbtdb.c
@@ -399,6 +399,23 @@ typedef isc_mutex_t nodelock_t;
#define NODE_WEAKDOWNGRADE(l) ((void)0)
#endif
+#if defined(ISC_PLATFORM_HAVESTDATOMIC)
+#if defined(__cplusplus)
+#include <isc/stdatomic.h>
+#else
+#include <stdatomic.h>
+#endif
+#define DNS_RBTDB_STDATOMIC 1
+#define DNS_RBTDB_INC(x) atomic_fetch_add(&(x), (1))
+#define DNS_RBTDB_LOAD(x) atomic_load(&(x))
+#elif defined(ISC_PLATFORM_HAVEXADD)
+#define DNS_RBTDB_INC(x) isc_atomic_xadd((int *)&(x), 1);
+#define DNS_RBTDB_LOAD(x) isc_atomic_xadd((int *)&(x), 0);
+#else
+#define DNS_RBTDB_INC(x) ((x)++)
+#define DNS_RBTDB_LOAD(x) (x)
+#endif
+
/*%
* Whether to rate-limit updating the LRU to avoid possible thread contention.
* Our performance measurement has shown the cost is marginal, so it's defined
@@ -457,7 +474,11 @@ typedef struct rdatasetheader {
* this rdataset.
*/
- uint32_t count;
+#ifdef DNS_RBTDB_STDATOMIC
+ _Atomic(uint32_t) count;
+#else
+ uint32_t count;
+#endif
/*%<
* Monotonously increased every time this rdataset is bound so that
* it is used as the base of the starting point in DNS responses
@@ -952,7 +973,11 @@ static char FILE_VERSION[32] = "\0";
* that indicates that the database does not implement cyclic
* processing.
*/
+#ifdef DNS_RBTDB_STDATOMIC
+static _Atomic(unsigned int) init_count;
+#else
static unsigned int init_count;
+#endif
/*
* Locking
@@ -3322,7 +3347,7 @@ bind_rdataset(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node, rdatasetheader_t *header,
rdataset->private2 = node;
raw = (unsigned char *)header + sizeof(*header);
rdataset->private3 = raw;
- rdataset->count = header->count++;
+ rdataset->count = DNS_RBTDB_INC(header->count);
if (rdataset->count == UINT32_MAX)
rdataset->count = 0;
@@ -5924,10 +5949,10 @@ cache_findrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
}
}
- NODE_UNLOCK(lock, locktype);
-
- if (found == NULL)
+ if (found == NULL) {
+ NODE_UNLOCK(lock, locktype);
return (ISC_R_NOTFOUND);
+ }
if (NEGATIVE(found)) {
/*
@@ -5939,6 +5964,8 @@ cache_findrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
result = DNS_R_NCACHENXRRSET;
}
+ NODE_UNLOCK(lock, locktype);
+
update_cachestats(rbtdb, result);
return (result);
@@ -6839,7 +6866,7 @@ addrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
newheader->attributes |= RDATASET_ATTR_ZEROTTL;
newheader->noqname = NULL;
newheader->closest = NULL;
- newheader->count = isc_atomic_xadd((int32_t*)&init_count, 1);
+ newheader->count = DNS_RBTDB_INC(init_count);
newheader->trust = rdataset->trust;
newheader->additional_auth = NULL;
newheader->additional_glue = NULL;
@@ -7035,7 +7062,7 @@ subtractrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
newheader->trust = 0;
newheader->noqname = NULL;
newheader->closest = NULL;
- newheader->count = isc_atomic_xadd((int32_t*)&init_count, 1);
+ newheader->count = DNS_RBTDB_INC(init_count);
newheader->additional_auth = NULL;
newheader->additional_glue = NULL;
newheader->last_used = 0;
@@ -7481,7 +7508,7 @@ loading_addrdataset(void *arg, dns_name_t *name, dns_rdataset_t *rdataset) {
newheader->serial = 1;
newheader->noqname = NULL;
newheader->closest = NULL;
- newheader->count = isc_atomic_xadd((int32_t*)&init_count, 1);
+ newheader->count = DNS_RBTDB_INC(init_count);
newheader->additional_auth = NULL;
newheader->additional_glue = NULL;
newheader->last_used = 0;
--
2.26.2