From: Sun Ke <sunke32@huawei.com>
Date: Mon, 1 Feb 2021 07:57:05 +0000 (+0800)
Subject: src/swapon.c: initiate p to NULL
X-Git-Tag: v2022.05.01~565
X-Git-Url: http://git.apps.os.sepia.ceph.com/?p=xfstests-dev.git;a=commitdiff_plain;h=f961a4b9fe8762731749addbe471773ef2e4f6e5

src/swapon.c: initiate p to NULL

when run make, show:
swapon.c:135:3: warning: 'p' may be used uninitialized in this function
[-Wmaybe-uninitialized]
   memcpy(p, buf, BUF_SIZE);
      ^~~~~~~~~~~~~~~~~~~~~~~~

This's a fake uninitialized warning.
gcc think the 'p' can be used uninitialized at here when verb is
TEST_MWRITE_BEFORE_AND_MWRITE_AFTER:
    case TEST_MWRITE_BEFORE_AND_MWRITE_AFTER:
	memcpy(p, buf, BUF_SIZE);
	break;

But, if verb is TEST_MWRITE_BEFORE_AND_MWRITE_AFTER, the 'p' will be
initialized by:
    switch (verb) {
    case TEST_MWRITE_BEFORE_AND_MWRITE_AFTER:
    case TEST_MWRITE_BEFORE:
	p = mmap(NULL, BUF_SIZE, PROT_WRITE | PROT_READ, MAP_SHARED,

Silent the warning by initializing p to NULL anyway.

Signed-off-by: Sun Ke <sunke32@huawei.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
---

diff --git a/src/swapon.c b/src/swapon.c
index afaed405..fe8949a3 100644
--- a/src/swapon.c
+++ b/src/swapon.c
@@ -41,7 +41,7 @@ int main(int argc, char **argv)
 		.sa_handler	= handle_signal,
 	};
 	enum verbs verb = TEST_SWAPON;
-	void *p;
+	void *p = NULL;
 	ssize_t sz;
 	int fd = -1;
 	int ret, c;