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Use atomic operations to access the trust byte in ncache data

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Protect the access to the trust byte in the ncache data with relaxed
atomic operation to mimick the current behaviour.  This will teach
TSAN that the concurrent access is fine.
This commit is contained in:
Ondřej Surý 2024-04-11 03:16:12 +02:00
parent 4ef755ffb0
commit eb1829b970
No known key found for this signature in database
GPG Key ID: 2820F37E873DEA41
1 changed files with 14 additions and 6 deletions
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20
lib/dns/ncache.c
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@ -42,6 +42,14 @@
*
*/
static uint8_t
atomic_getuint8(isc_buffer_t *b) {
atomic_uchar *cp = isc_buffer_current(b);
uint8_t ret = atomic_load_relaxed(cp);
isc_buffer_forward(b, 1);
return (ret);
}
static isc_result_t
addoptout(dns_message_t *message, dns_db_t *cache, dns_dbnode_t *node,
dns_rdatatype_t covers, isc_stdtime_t now, dns_ttl_t minttl,
@ -493,10 +501,10 @@ rdataset_count(dns_rdataset_t *rdataset) {
static void
rdataset_settrust(dns_rdataset_t *rdataset, dns_trust_t trust) {
unsigned char *raw;
atomic_uchar *raw;
raw = rdataset->ncache.raw;
raw[-1] = (unsigned char)trust;
raw = (atomic_uchar *)rdataset->ncache.raw;
atomic_store_relaxed(&raw[-1], (unsigned char)trust);
rdataset->trust = trust;
}
@ -548,7 +556,7 @@ dns_ncache_getrdataset(dns_rdataset_t *ncacherdataset, dns_name_t *name,
ttype = isc_buffer_getuint16(&source);
if (ttype == type && dns_name_equal(&tname, name)) {
trust = isc_buffer_getuint8(&source);
trust = atomic_getuint8(&source);
INSIST(trust <= dns_trust_ultimate);
isc_buffer_remainingregion(&source, &remaining);
break;
@ -627,7 +635,7 @@ dns_ncache_getsigrdataset(dns_rdataset_t *ncacherdataset, dns_name_t *name,
}
INSIST(remaining.length >= 1);
trust = isc_buffer_getuint8(&source);
trust = atomic_getuint8(&source);
INSIST(trust <= dns_trust_ultimate);
isc_region_consume(&remaining, 1);
@ -705,7 +713,7 @@ dns_ncache_current(dns_rdataset_t *ncacherdataset, dns_name_t *found,
INSIST(remaining.length >= 5);
type = isc_buffer_getuint16(&source);
trust = isc_buffer_getuint8(&source);
trust = atomic_getuint8(&source);
INSIST(trust <= dns_trust_ultimate);
isc_buffer_remainingregion(&source, &remaining);