From: madhuparnabhowmik10@gmail.com
To: isdn@linux-pingi.de, davem@davemloft.net, arnd@arndb.de,
gregkh@linuxfoundation.org, edumazet@google.com
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
andrianov@ispras.ru, ldv-project@linuxtesting.org,
Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Subject: [PATCH] drivers: isdn: capi: Fix data-race bug
Date: Wed, 22 Jul 2020 22:53:29 +0530 [thread overview]
Message-ID: <20200722172329.16727-1-madhuparnabhowmik10@gmail.com> (raw)
From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
In capi_init(), after register_chrdev() the file operation callbacks
can be called. However capinc_tty_init() is called later.
Since capiminors and capinc_tty_driver are initialized in
capinc_tty_init(), their initialization can race with their usage
in various callbacks like in capi_release().
Therefore, call capinc_tty_init() before register_chrdev to avoid
such race conditions.
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
---
drivers/isdn/capi/capi.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)
diff --git a/drivers/isdn/capi/capi.c b/drivers/isdn/capi/capi.c
index 85767f52fe3c..7e8ab48a15af 100644
--- a/drivers/isdn/capi/capi.c
+++ b/drivers/isdn/capi/capi.c
@@ -1332,7 +1332,7 @@ static int __init capinc_tty_init(void)
return 0;
}
-static void __exit capinc_tty_exit(void)
+static void capinc_tty_exit(void)
{
tty_unregister_driver(capinc_tty_driver);
put_tty_driver(capinc_tty_driver);
@@ -1420,29 +1420,28 @@ static int __init capi_init(void)
if (ret)
return ret;
+ if (capinc_tty_init() < 0) {
+ kcapi_exit();
+ return -ENOMEM;
+ }
+
major_ret = register_chrdev(capi_major, "capi20", &capi_fops);
if (major_ret < 0) {
printk(KERN_ERR "capi20: unable to get major %d\n", capi_major);
+ capinc_tty_exit();
kcapi_exit();
return major_ret;
}
capi_class = class_create(THIS_MODULE, "capi");
if (IS_ERR(capi_class)) {
unregister_chrdev(capi_major, "capi20");
+ capinc_tty_exit();
kcapi_exit();
return PTR_ERR(capi_class);
}
device_create(capi_class, NULL, MKDEV(capi_major, 0), NULL, "capi20");
- if (capinc_tty_init() < 0) {
- device_destroy(capi_class, MKDEV(capi_major, 0));
- class_destroy(capi_class);
- unregister_chrdev(capi_major, "capi20");
- kcapi_exit();
- return -ENOMEM;
- }
-
proc_init();
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
--
2.17.1
next reply other threads:[~2020-07-22 17:23 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-22 17:23 madhuparnabhowmik10 [this message]
2020-07-22 18:41 ` Arnd Bergmann
2020-07-23 22:11 ` David Miller
2020-07-24 4:48 ` Madhuparna Bhowmik
2020-07-24 6:57 ` Greg KH
2020-07-24 14:58 ` Madhuparna Bhowmik
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