linux-kernel - [PATCH] chardev: set variable ret to -EBUSY before checking minor range overlap

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190405135306.10188-1-cgxu519@gmx.com>
Date:   Fri,  5 Apr 2019 21:53:06 +0800
From:   Chengguang Xu <cgxu519@....com>
To:     gregkh@...uxfoundation.org, dan.carpenter@...cle.com
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        Chengguang Xu <cgxu519@....com>
Subject: [PATCH] chardev: set variable ret to -EBUSY before checking minor range overlap

When allocating dynamic major, the minor range overlap check
in __register_chrdev_region() will not fail, so actually
there is no real case to passing non negative error code to
caller. However, set variable ret to -EBUSY before chekcking
minor range overlap will avoid false-positive warning from
code analyzing tool(like Smatch) and also make the code more
easy to understand.

Suggested-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: Chengguang Xu <cgxu519@....com>
---
 fs/char_dev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/char_dev.c b/fs/char_dev.c
index df6a54045ac4..00dfe17871ac 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -98,7 +98,7 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor,
 			   int minorct, const char *name)
 {
 	struct char_device_struct *cd, *curr, *prev = NULL;
-	int ret -EBUSY;
+	int ret;
 	int i;

 	if (major >= CHRDEV_MAJOR_MAX) {
@@ -129,6 +129,7 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor,
 		major = ret;
 	}

+	ret = -EBUSY;
 	i = major_to_index(major);
 	for (curr = chrdevs[i]; curr; prev = curr, curr = curr->next) {
 		if (curr->major < major)
--
2.17.2