linux-kernel - [PATCH] selftests/mm: fix resource leaks in child_vmsplice_memcmp

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Date:   Tue,  4 Apr 2023 11:12:56 +0800
From:   Feng Jiang <jiangfeng@...inos.cn>
To:     akpm@...ux-foundation.org, shuah@...nel.org
Cc:     linux-mm@...ck.org, linux-kselftest@...r.kernel.org,
        linux-kernel@...r.kernel.org, Feng Jiang <jiangfeng@...inos.cn>,
        Ming Xie <xieming@...inos.cn>
Subject: [PATCH] selftests/mm: fix resource leaks in child_vmsplice_memcmp_fn

When the function returns, the 'new' and 'old' are not freed
and the 'fds[]' are not closed, which can lead to resource leaks.

Signed-off-by: Feng Jiang <jiangfeng@...inos.cn>
Suggested-by: Ming Xie <xieming@...inos.cn>
---
 tools/testing/selftests/mm/cow.c | 43 ++++++++++++++++++++++++--------
 1 file changed, 32 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/cow.c
index c0dd2dfca51b..b8aec05d56f4 100644
--- a/tools/testing/selftests/mm/cow.c
+++ b/tools/testing/selftests/mm/cow.c
@@ -193,26 +193,38 @@ static int child_vmsplice_memcmp_fn(char *mem, size_t size,
 	char *old, *new;
 	int fds[2];
 	char buf;
+	int ret;
 
 	old = malloc(size);
 	new = malloc(size);
+	if (!old || !new) {
+		ret = -ENOMEM;
+		goto free;
+	}
 
 	/* Backup the original content. */
 	memcpy(old, mem, size);
 
-	if (pipe(fds) < 0)
-		return -errno;
+	if (pipe(fds) < 0) {
+		ret = -errno;
+		goto free;
+	}
 
 	/* Trigger a read-only pin. */
 	transferred = vmsplice(fds[1], &iov, 1, 0);
-	if (transferred < 0)
-		return -errno;
-	if (transferred == 0)
-		return -EINVAL;
+	if (transferred < 0) {
+		ret = -errno;
+		goto close_pipe;
+	} else if (transferred == 0) {
+		ret = -EINVAL;
+		goto close_pipe;
+	}
 
 	/* Unmap it from our page tables. */
-	if (munmap(mem, size) < 0)
-		return -errno;
+	if (munmap(mem, size) < 0) {
+		ret = -errno;
+		goto close_pipe;
+	}
 
 	/* Wait until the parent modified it. */
 	write(comm_pipes->child_ready[1], "0", 1);
@@ -222,11 +234,20 @@ static int child_vmsplice_memcmp_fn(char *mem, size_t size,
 	/* See if we still read the old values via the pipe. */
 	for (total = 0; total < transferred; total += cur) {
 		cur = read(fds[0], new + total, transferred - total);
-		if (cur < 0)
-			return -errno;
+		if (cur < 0) {
+			ret = -errno;
+			goto close_pipe;
+		}
 	}
 
-	return memcmp(old, new, transferred);
+	ret = memcmp(old, new, transferred);
+close_pipe:
+	close(fds[0]);
+	close(fds[1]);
+free:
+	free(old);
+	free(new);
+	return ret;
 }
 
 typedef int (*child_fn)(char *mem, size_t size, struct comm_pipes *comm_pipes);
-- 
2.39.2