69 lines
2.3 KiB
Diff
69 lines
2.3 KiB
Diff
From a241c69920fe5a609305fb435b593c2d997626aa Mon Sep 17 00:00:00 2001
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From: Mark Andrews <marka@isc.org>
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Date: Thu, 15 Oct 2020 15:05:30 +1100
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Subject: [PATCH] Lock read of refs when atomics are not available.
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WARNING: ThreadSanitizer: data race
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Read of size 4 at 0x000000000001 by thread T1 (mutexes: write M1):
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#0 zone_iattach lib/dns/zone.c:5412:2
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#1 soa_query lib/dns/zone.c:12725:2
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#2 dispatch lib/isc/task.c:1157:7
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#3 run lib/isc/task.c:1331:2
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Previous write of size 4 at 0x000000000001 by thread T2 (mutexes: write M2):
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#0 dns_zone_detach lib/dns/zone.c:5346:2
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#1 ns_server_refreshcommand bin/named/./server.c:9880:3
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#2 ns_control_docommand bin/named/control.c:247:12
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#3 control_recvmessage bin/named/controlconf.c:469:13
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#4 dispatch lib/isc/task.c:1157:7
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#5 run lib/isc/task.c:1331:2
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Conflict: NA
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Reference: https://gitlab.isc.org/isc-projects/bind9/-/commit/a241c69920fe5a609305fb435b593c2d997626aa
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---
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lib/isc/include/isc/refcount.h | 2 +-
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lib/isc/refcount.c | 15 +++++++++++++++
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2 files changed, 16 insertions(+), 1 deletion(-)
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diff --git a/lib/isc/include/isc/refcount.h b/lib/isc/include/isc/refcount.h
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index 5d1a5d2bbf..1c9696fc6b 100644
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--- a/lib/isc/include/isc/refcount.h
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+++ b/lib/isc/include/isc/refcount.h
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@@ -211,7 +211,7 @@ typedef struct isc_refcount {
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ISC_ERROR_RUNTIMECHECK(_result == ISC_R_SUCCESS); \
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} while (0)
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-#define isc_refcount_current(rp) ((unsigned int)((rp)->refs))
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+unsigned int isc_refcount_current(isc_refcount_t *rp);
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/*%
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* Increments the reference count, returning the new value in
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diff --git a/lib/isc/refcount.c b/lib/isc/refcount.c
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index d83c82fe7f..0d961effe1 100644
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--- a/lib/isc/refcount.c
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+++ b/lib/isc/refcount.c
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@@ -19,6 +19,21 @@
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#include <isc/result.h>
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#include <isc/util.h>
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+#if defined(ISC_PLATFORM_USETHREADS) && !defined(ISC_REFCOUNT_HAVEATOMIC)
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+unsigned int
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+isc_refcount_current(isc_refcount_t *ref) {
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+ isc_result_t result;
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+ unsigned int answer;
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+
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+ result = isc_mutex_lock(&ref->lock);
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+ ISC_ERROR_RUNTIMECHECK(result == ISC_R_SUCCESS);
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+ answer = ref->refs;
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+ result = isc_mutex_unlock(&ref->lock);
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+ ISC_ERROR_RUNTIMECHECK(result == ISC_R_SUCCESS);
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+ return (answer);
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+}
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+#endif
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+
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isc_result_t
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isc_refcount_init(isc_refcount_t *ref, unsigned int n) {
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REQUIRE(ref != NULL);
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--
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2.23.0
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