linux-hardening - [PATCH v2 1/4] pstore: inode: Convert kfree() usage to _

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Message-Id: <20231205182622.1329923-1-keescook@chromium.org>
Date: Tue,  5 Dec 2023 10:26:14 -0800
From: Kees Cook <keescook@...omium.org>
To: "Guilherme G. Piccoli" <gpiccoli@...lia.com>
Cc: Kees Cook <keescook@...omium.org>,
	Tony Luck <tony.luck@...el.com>,
	linux-hardening@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 1/4] pstore: inode: Convert kfree() usage to __free(kfree)

Mostly as an example to myself, replace a simple allocation pattern with
the automatic kfree cleanup features now exposed by cleanup.h.

Cc: "Guilherme G. Piccoli" <gpiccoli@...lia.com>
Cc: Tony Luck <tony.luck@...el.com>
Cc: linux-hardening@...r.kernel.org
Signed-off-by: Kees Cook <keescook@...omium.org>
---
 fs/pstore/inode.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index d41c20d1b5e8..20f3452c8196 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -23,6 +23,7 @@
 #include <linux/pstore.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
+#include <linux/cleanup.h>
 
 #include "internal.h"
 
@@ -64,7 +65,7 @@ static void free_pstore_private(struct pstore_private *private)
 static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
 {
 	struct pstore_private *ps = s->private;
-	struct pstore_ftrace_seq_data *data;
+	struct pstore_ftrace_seq_data *data __free(kfree) = NULL;
 
 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data)
@@ -72,13 +73,10 @@ static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
 
 	data->off = ps->total_size % REC_SIZE;
 	data->off += *pos * REC_SIZE;
-	if (data->off + REC_SIZE > ps->total_size) {
-		kfree(data);
+	if (data->off + REC_SIZE > ps->total_size)
 		return NULL;
-	}
-
-	return data;
 
+	return_ptr(data);
 }
 
 static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
-- 
2.34.1