Merge branch 'cherry-pick-e4671ef2' into 'v9_16'

Merge branch 'ondrej/fix-crash-on-arm64-from-weak-cmpxchg' into 'master'

See merge request isc-projects/bind9!3100

.gitlab-ci.yml

@@ -55,6 +55,11 @@ stages:
     - linux
     - amd64
 
+.linux-arm64: &linux_arm64
+  tags:
+    - linux
+    - arm64
+
 .linux-i386: &linux_i386
   tags:
     - linux
@@ -109,6 +114,10 @@ stages:
   image: "$CI_REGISTRY_IMAGE:debian-sid-amd64"
   <<: *linux_amd64
 
+.debian-sid-arm64: &debian_sid_arm64_image
+  image: "$CI_REGISTRY_IMAGE:debian-sid-arm64"
+  <<: *linux_arm64
+
 .debian-sid-i386: &debian_sid_i386_image
   image: "$CI_REGISTRY_IMAGE:debian-sid-i386"
   <<: *linux_i386
@@ -731,6 +740,39 @@ unit:tarball:sid:amd64:
   only:
     - tags
 
+# Jobs for regular GCC builds on Debian Sid (arm64)
+
+gcc:sid:arm64:
+  variables:
+    CC: gcc
+    CFLAGS: "${CFLAGS_COMMON} -O3"
+    EXTRA_CONFIGURE: "--enable-dnstap --with-libidn2"
+    RUN_MAKE_INSTALL: 1
+    MAKE: bear make
+  <<: *debian_sid_arm64_image
+  <<: *build_job
+
+system:gcc:sid:arm64:
+  <<: *debian_sid_arm64_image
+  <<: *system_test_job
+  dependencies:
+    - gcc:sid:arm64
+  needs: ["gcc:sid:arm64"]
+
+unit:gcc:sid:arm64:
+  <<: *debian_sid_arm64_image
+  <<: *unit_test_job
+  dependencies:
+    - gcc:sid:arm64
+  needs: ["gcc:sid:arm64"]
+
+cppcheck:gcc:sid:arm64:
+  <<: *debian_sid_arm64_image
+  <<: *cppcheck_job
+  dependencies:
+    - gcc:sid:arm64
+  needs: ["gcc:sid:arm64"]
+
 # Jobs for regular GCC builds on Debian Sid (i386)
 
 gcc:sid:i386:

lib/isc/app.c

@@ -228,8 +228,6 @@ isc_result_t
 isc_app_ctxrun(isc_appctx_t *ctx) {
 	isc_event_t *event, *next_event;
 	isc_task_t *task;
-	bool exp_false = false;
-	bool exp_true = true;
 
 	REQUIRE(VALID_APPCTX(ctx));
 
@@ -237,8 +235,8 @@ isc_app_ctxrun(isc_appctx_t *ctx) {
 	REQUIRE(main_thread == GetCurrentThread());
 #endif /* ifdef WIN32 */
 
-	if (atomic_compare_exchange_weak_acq_rel(&ctx->running, &exp_false,
-						 true) == true)
+	if (atomic_compare_exchange_strong_acq_rel(
+		    &ctx->running, &(bool){ false }, true) == true)
 	{
 		/*
 		 * Post any on-run events (in FIFO order).
@@ -344,9 +342,9 @@ isc_app_ctxrun(isc_appctx_t *ctx) {
 			}
 		}
 #endif /* WIN32 */
-		exp_true = true;
-		if (atomic_compare_exchange_weak_acq_rel(&ctx->want_reload,
-							 &exp_true, false)) {
+		if (atomic_compare_exchange_strong_acq_rel(
+			    &ctx->want_reload, &(bool){ true }, false))
+		{
 			return (ISC_R_RELOAD);
 		}
 
@@ -363,10 +361,9 @@ isc_app_ctxrun(isc_appctx_t *ctx) {
 isc_result_t
 isc_app_run(void) {
 	isc_result_t result;
-	bool exp_false = false;
 
-	REQUIRE(atomic_compare_exchange_weak_acq_rel(&is_running, &exp_false,
-						     true) == true);
+	REQUIRE(atomic_compare_exchange_strong_acq_rel(
+			&is_running, &(bool){ false }, true) == true);
 	result = isc_app_ctxrun(&isc_g_appctx);
 	atomic_store_release(&is_running, false);
 
@@ -380,8 +377,6 @@ isc_app_isrunning() {
 
 void
 isc_app_ctxshutdown(isc_appctx_t *ctx) {
-	bool exp_false = false;
-
 	REQUIRE(VALID_APPCTX(ctx));
 
 	REQUIRE(atomic_load_acquire(&ctx->running));
@@ -389,8 +384,8 @@ isc_app_ctxshutdown(isc_appctx_t *ctx) {
 	/* If ctx->shutdown_requested == true, we are already shutting
 	 * down and we want to just bail out.
 	 */
-	if (atomic_compare_exchange_weak_acq_rel(&ctx->shutdown_requested,
-						 &exp_false, true))
+	if (atomic_compare_exchange_strong_acq_rel(&ctx->shutdown_requested,
+						   &(bool){ false }, true))
 	{
 #ifdef WIN32
 		SetEvent(ctx->hEvents[SHUTDOWN_EVENT]);
@@ -480,10 +475,9 @@ isc_app_finish(void) {
 
 void
 isc_app_block(void) {
-	bool exp_false = false;
 	REQUIRE(atomic_load_acquire(&isc_g_appctx.running));
-	REQUIRE(atomic_compare_exchange_weak_acq_rel(&isc_g_appctx.blocked,
-						     &exp_false, true));
+	REQUIRE(atomic_compare_exchange_strong_acq_rel(&isc_g_appctx.blocked,
+						       &(bool){ false }, true));
 
 #ifdef WIN32
 	blockedthread = GetCurrentThread();
@@ -499,11 +493,9 @@ isc_app_block(void) {
 
 void
 isc_app_unblock(void) {
-	bool exp_true = true;
-
 	REQUIRE(atomic_load_acquire(&isc_g_appctx.running));
-	REQUIRE(atomic_compare_exchange_weak_acq_rel(&isc_g_appctx.blocked,
-						     &exp_true, false));
+	REQUIRE(atomic_compare_exchange_strong_acq_rel(&isc_g_appctx.blocked,
+						       &(bool){ true }, false));
 
 #ifdef WIN32
 	REQUIRE(blockedthread == GetCurrentThread());

lib/isc/include/isc/atomic.h

@@ -65,3 +65,6 @@
 #define atomic_compare_exchange_weak_acq_rel(o, e, d) \
 	atomic_compare_exchange_weak_explicit(        \
 		(o), (e), (d), memory_order_acq_rel, memory_order_acquire)
+#define atomic_compare_exchange_strong_acq_rel(o, e, d) \
+	atomic_compare_exchange_strong_explicit(        \
+		(o), (e), (d), memory_order_acq_rel, memory_order_acquire)

lib/isc/rwlock.c

@@ -400,14 +400,10 @@ isc__rwlock_lock(isc_rwlock_t *rwl, isc_rwlocktype_t type) {
 			break;
 		}
 
-		while (1) {
-			int_fast32_t zero = 0;
-			if (atomic_compare_exchange_weak_acq_rel(
-				    &rwl->cnt_and_flag, &zero, WRITER_ACTIVE))
-			{
-				break;
-			}
-
+		while (!atomic_compare_exchange_weak_acq_rel(
+			&rwl->cnt_and_flag, &(int_fast32_t){ 0 },
+			WRITER_ACTIVE))
+		{
 			/* Another active reader or writer is working. */
 			LOCK(&rwl->lock);
 			if (atomic_load_acquire(&rwl->cnt_and_flag) != 0) {
@@ -494,8 +490,8 @@ isc_rwlock_trylock(isc_rwlock_t *rwl, isc_rwlocktype_t type) {
 	} else {
 		/* Try locking without entering the waiting queue. */
 		int_fast32_t zero = 0;
-		if (!atomic_compare_exchange_weak_acq_rel(&rwl->cnt_and_flag,
-							  &zero, WRITER_ACTIVE))
+		if (!atomic_compare_exchange_strong_acq_rel(
+			    &rwl->cnt_and_flag, &zero, WRITER_ACTIVE))
 		{
 			return (ISC_R_LOCKBUSY);
 		}
@@ -519,28 +515,26 @@ isc_result_t
 isc_rwlock_tryupgrade(isc_rwlock_t *rwl) {
 	REQUIRE(VALID_RWLOCK(rwl));
 
-	{
-		int_fast32_t reader_incr = READER_INCR;
+	int_fast32_t reader_incr = READER_INCR;
 
-		/* Try to acquire write access. */
-		atomic_compare_exchange_weak_acq_rel(
-			&rwl->cnt_and_flag, &reader_incr, WRITER_ACTIVE);
+	/* Try to acquire write access. */
+	atomic_compare_exchange_strong_acq_rel(&rwl->cnt_and_flag, &reader_incr,
+					       WRITER_ACTIVE);
+	/*
+	 * There must have been no writer, and there must have
+	 * been at least one reader.
+	 */
+	INSIST((reader_incr & WRITER_ACTIVE) == 0 &&
+	       (reader_incr & ~WRITER_ACTIVE) != 0);
+
+	if (reader_incr == READER_INCR) {
 		/*
-		 * There must have been no writer, and there must have
-		 * been at least one reader.
+		 * We are the only reader and have been upgraded.
+		 * Now jump into the head of the writer waiting queue.
 		 */
-		INSIST((reader_incr & WRITER_ACTIVE) == 0 &&
-		       (reader_incr & ~WRITER_ACTIVE) != 0);
-
-		if (reader_incr == READER_INCR) {
-			/*
-			 * We are the only reader and have been upgraded.
-			 * Now jump into the head of the writer waiting queue.
-			 */
-			atomic_fetch_sub_release(&rwl->write_completions, 1);
-		} else {
-			return (ISC_R_LOCKBUSY);
-		}
+		atomic_fetch_sub_release(&rwl->write_completions, 1);
+	} else {
+		return (ISC_R_LOCKBUSY);
 	}
 
 	return (ISC_R_SUCCESS);