From: Willy Tarreau <w@1wt.eu>
Date: Wed, 23 Feb 2022 07:57:59 +0000 (+0100)
Subject: MINOR: pools: store the allocated size for each pool
X-Git-Tag: v2.6-dev2~77
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=96d5bc7379f04aa7652d786bce15f2501d564515;p=thirdparty%2Fhaproxy.git

MINOR: pools: store the allocated size for each pool

The allocated size is the visible size plus the extra storage. Since
for now we can store up to two extra elements (mark and tracer), it's
convenient because now we know that the mark is always stored at
->size, and the tracer is always before ->alloc_sz.
---

diff --git a/include/haproxy/pool-t.h b/include/haproxy/pool-t.h
index 0a8f9dd02a..a7b3dda783 100644
--- a/include/haproxy/pool-t.h
+++ b/include/haproxy/pool-t.h
@@ -113,7 +113,7 @@ struct pool_head {
 	unsigned int flags;	/* MEM_F_* */
 	unsigned int users;	/* number of pools sharing this zone */
 	unsigned int failed;	/* failed allocations */
-	/* 32-bit hole here */
+	unsigned int alloc_sz;	/* allocated size (includes hidden fields) */
 	struct list list;	/* list of all known pools */
 	char name[12];		/* name of the pool */
 	struct pool_cache_head cache[MAX_THREADS]; /* pool caches */
diff --git a/include/haproxy/pool.h b/include/haproxy/pool.h
index acab81d97b..90d928aded 100644
--- a/include/haproxy/pool.h
+++ b/include/haproxy/pool.h
@@ -87,7 +87,8 @@
 #endif // DEBUG_MEMORY_POOLS
 
 /* It's possible to trace callers of pool_free() by placing their pointer
- * after the end of the area and the optional mark above.
+ * after the end of the area and the optional mark above, which means the
+ * end of the allocated array.
  */
 #if defined(DEBUG_POOL_TRACING)
 # define POOL_EXTRA_CALLER (sizeof(void *))
@@ -96,7 +97,7 @@
 		typeof(pool) __p = (pool);				\
 		typeof(item) __i = (item);				\
 		typeof(caller) __c = (caller);				\
-		*(typeof(caller)*)(((char *)__i) + __p->size + POOL_EXTRA_MARK) = __c; \
+		*(typeof(caller)*)(((char *)__i) + __p->alloc_sz - sizeof(void*)) = __c; \
 	} while (0)
 
 #else // DEBUG_POOL_TRACING
diff --git a/src/pool.c b/src/pool.c
index cb1f76891a..f203397b06 100644
--- a/src/pool.c
+++ b/src/pool.c
@@ -252,6 +252,7 @@ struct pool_head *create_pool(char *name, unsigned int size, unsigned int flags)
 			return NULL;
 		if (name)
 			strlcpy2(pool->name, name, sizeof(pool->name));
+		pool->alloc_sz = size + POOL_EXTRA;
 		pool->size = size;
 		pool->flags = flags;
 		LIST_APPEND(start, &pool->list);
@@ -276,7 +277,7 @@ struct pool_head *create_pool(char *name, unsigned int size, unsigned int flags)
 void *pool_get_from_os(struct pool_head *pool)
 {
 	if (!pool->limit || pool->allocated < pool->limit) {
-		void *ptr = pool_alloc_area(pool->size + POOL_EXTRA);
+		void *ptr = pool_alloc_area(pool->alloc_sz);
 		if (ptr) {
 			_HA_ATOMIC_INC(&pool->allocated);
 			return ptr;
@@ -301,7 +302,7 @@ void pool_put_to_os(struct pool_head *pool, void *ptr)
 	*(uint32_t *)ptr = 0xDEADADD4;
 #endif /* DEBUG_UAF */
 
-	pool_free_area(ptr, pool->size + POOL_EXTRA);
+	pool_free_area(ptr, pool->alloc_sz);
 	_HA_ATOMIC_DEC(&pool->allocated);
 }