From: Mukund Sivaraman <muks@isc.org>
Date: Mon, 9 Mar 2015 04:59:03 +0000 (+0530)
Subject: Fix a possible race in updating stats counters (#38826)
X-Git-Tag: v9.11.0a1~923
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=24f2cc7d06e4bb6625f90323e44b42e0cad63588;p=thirdparty%2Fbind9.git

Fix a possible race in updating stats counters (#38826)

and do some other isc mem cleanups.
---

diff --git a/CHANGES b/CHANGES
index a603cbca4c7..955658b63d3 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+4094.	[bug]		Fix a possible race in updating stats counters.
+			[RT #38826]
+
 4083.	[cleanup]	Print the number of CPUs and UDP listeners
 			consistently in the log and in "rndc status"
 			output; indicate whether threads are supported
diff --git a/lib/isc/mem.c b/lib/isc/mem.c
index 2e9308fae2a..669ea2a3763 100644
--- a/lib/isc/mem.c
+++ b/lib/isc/mem.c
@@ -1262,13 +1262,10 @@ isc___mem_get(isc_mem_t *ctx0, size_t size FLARG) {
 	}
 
 	ADD_TRACE(ctx, ptr, size, file, line);
-	if (ctx->hi_water != 0U && ctx->inuse > ctx->hi_water &&
-	    !ctx->is_overmem) {
+	if (ctx->hi_water != 0U && ctx->inuse > ctx->hi_water) {
 		ctx->is_overmem = ISC_TRUE;
-	}
-	if (ctx->hi_water != 0U && !ctx->hi_called &&
-	    ctx->inuse > ctx->hi_water) {
-		call_water = ISC_TRUE;
+		if (!ctx->hi_called)
+			call_water = ISC_TRUE;
 	}
 	if (ctx->inuse > ctx->maxinuse) {
 		ctx->maxinuse = ctx->inuse;
@@ -1279,7 +1276,7 @@ isc___mem_get(isc_mem_t *ctx0, size_t size FLARG) {
 	}
 	MCTXUNLOCK(ctx, &ctx->lock);
 
-	if (call_water)
+	if (call_water && (ctx->water != NULL))
 		(ctx->water)(ctx->water_arg, ISC_MEM_HIWATER);
 
 	return (ptr);
@@ -1323,18 +1320,15 @@ isc___mem_put(isc_mem_t *ctx0, void *ptr, size_t size FLARG) {
 	 * when the context was pushed over hi_water but then had
 	 * isc_mem_setwater() called with 0 for hi_water and lo_water.
 	 */
-	if (ctx->is_overmem &&
-	    (ctx->inuse < ctx->lo_water || ctx->lo_water == 0U)) {
+	if ((ctx->inuse < ctx->lo_water) || (ctx->lo_water == 0U)) {
 		ctx->is_overmem = ISC_FALSE;
-	}
-	if (ctx->hi_called &&
-	    (ctx->inuse < ctx->lo_water || ctx->lo_water == 0U)) {
-		if (ctx->water != NULL)
+		if (ctx->hi_called)
 			call_water = ISC_TRUE;
 	}
+
 	MCTXUNLOCK(ctx, &ctx->lock);
 
-	if (call_water)
+	if (call_water && (ctx->water != NULL))
 		(ctx->water)(ctx->water_arg, ISC_MEM_LOWATER);
 }
 
@@ -1387,8 +1381,8 @@ print_active(isc__mem_t *mctx, FILE *out) {
 			}
 		}
 		if (!found)
-			fprintf(out, "%s", isc_msgcat_get(isc_msgcat, ISC_MSGSET_MEM,
-						    ISC_MSG_NONE, "\tNone.\n"));
+			fputs(isc_msgcat_get(isc_msgcat, ISC_MSGSET_MEM,
+					     ISC_MSG_NONE, "\tNone.\n"), out);
 	}
 }
 #endif
@@ -1510,15 +1504,10 @@ isc___mem_allocate(isc_mem_t *ctx0, size_t size FLARG) {
 
 	REQUIRE(VALID_CONTEXT(ctx));
 
-	if ((ctx->flags & ISC_MEMFLAG_INTERNAL) != 0) {
-		MCTXLOCK(ctx, &ctx->lock);
-		si = mem_allocateunlocked((isc_mem_t *)ctx, size);
-	} else {
-		si = mem_allocateunlocked((isc_mem_t *)ctx, size);
-		MCTXLOCK(ctx, &ctx->lock);
-		if (si != NULL)
-			mem_getstats(ctx, si[-1].u.size);
-	}
+	MCTXLOCK(ctx, &ctx->lock);
+	si = mem_allocateunlocked((isc_mem_t *)ctx, size);
+	if (((ctx->flags & ISC_MEMFLAG_INTERNAL) == 0) && (si != NULL))
+		mem_getstats(ctx, si[-1].u.size);
 
 #if ISC_MEM_TRACKLINES
 	ADD_TRACE(ctx, si, si[-1].u.size, file, line);
@@ -1773,7 +1762,6 @@ isc__mem_setwater(isc_mem_t *ctx0, isc_mem_water_t water, void *water_arg,
 		ctx->water_arg = NULL;
 		ctx->hi_water = 0;
 		ctx->lo_water = 0;
-		ctx->hi_called = ISC_FALSE;
 	} else {
 		if (ctx->hi_called &&
 		    (ctx->water != water || ctx->water_arg != water_arg ||
@@ -2596,6 +2584,8 @@ json_renderctx(isc__mem_t *ctx, summarystat_t *summary, json_object *array) {
 	CHECKMEM(obj);
 	json_object_object_add(ctxobj, "pools", obj);
 
+	summary->contextsize += ctx->poolcnt * sizeof(isc_mempool_t);
+
 	obj = json_object_new_int64(ctx->hi_water);
 	CHECKMEM(obj);
 	json_object_object_add(ctxobj, "hiwater", obj);