From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Tue, 19 Mar 2024 22:18:21 +0000 (-0400)
Subject: mempool: Introduce COW_ZERO poison value
X-Git-Url: https://git.efficios.com/?a=commitdiff_plain;h=6ea98a7bc2e89649d4bb0888eac596429a7c1576;p=librseq.git

mempool: Introduce COW_ZERO poison value

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Id7fdfa0ceb8631e1b4bfe594d9e68c4d8663c6ef
---

diff --git a/src/rseq-mempool.c b/src/rseq-mempool.c
index 4508ff4..15dd4e5 100644
--- a/src/rseq-mempool.c
+++ b/src/rseq-mempool.c
@@ -56,11 +56,13 @@
 #define RANGE_HEADER_OFFSET	sizeof(struct rseq_mempool_range)
 
 #if RSEQ_BITS_PER_LONG == 64
-# define DEFAULT_PRIVATE_POISON_VALUE	0x5555555555555555ULL
+# define DEFAULT_COW_INIT_POISON_VALUE	0x5555555555555555ULL
 #else
-# define DEFAULT_PRIVATE_POISON_VALUE	0x55555555UL
+# define DEFAULT_COW_INIT_POISON_VALUE	0x55555555UL
 #endif
 
+#define DEFAULT_COW_ZERO_POISON_VALUE	0x0
+
 struct free_list_node;
 
 struct free_list_node {
@@ -952,7 +954,10 @@ struct rseq_mempool *rseq_mempool_create(const char *pool_name,
 		attr.stride = RSEQ_MEMPOOL_STRIDE;	/* Use default */
 	if (attr.robust_set && !attr.poison_set) {
 		attr.poison_set = true;
-		attr.poison = DEFAULT_PRIVATE_POISON_VALUE;
+		if (attr.populate_policy != RSEQ_MEMPOOL_POPULATE_PRIVATE_ALL)
+			attr.poison = DEFAULT_COW_INIT_POISON_VALUE;
+		else
+			attr.poison = DEFAULT_COW_ZERO_POISON_VALUE;
 	}
 	if (item_len > attr.stride || attr.stride < (size_t) rseq_get_page_len() ||
 			!is_pow2(attr.stride)) {