From: Johan Hovold <johan@kernel.org>
To: Mathias Nyman <mathias.nyman@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
Johan Hovold <johan@kernel.org>,
stable@vger.kernel.org, Lu Baolu <baolu.lu@linux.intel.com>
Subject: [PATCH] USB: xhci: dbc: fix tty registration race
Date: Tue, 28 Sep 2021 14:04:00 +0200 [thread overview]
Message-ID: <20210928120400.20704-1-johan@kernel.org> (raw)
Make sure to allocate resources before registering the tty device to
avoid having a racing open() and write() fail to enable rx or
dereference a NULL pointer when accessing the uninitialised fifo.
Fixes: dfba2174dc42 ("usb: xhci: Add DbC support in xHCI driver")
Cc: stable@vger.kernel.org # 4.16
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/usb/host/xhci-dbgtty.c | 28 +++++++++++++---------------
1 file changed, 13 insertions(+), 15 deletions(-)
diff --git a/drivers/usb/host/xhci-dbgtty.c b/drivers/usb/host/xhci-dbgtty.c
index 6e784f2fc26d..eb46e642e87a 100644
--- a/drivers/usb/host/xhci-dbgtty.c
+++ b/drivers/usb/host/xhci-dbgtty.c
@@ -408,40 +408,38 @@ static int xhci_dbc_tty_register_device(struct xhci_dbc *dbc)
return -EBUSY;
xhci_dbc_tty_init_port(dbc, port);
- tty_dev = tty_port_register_device(&port->port,
- dbc_tty_driver, 0, NULL);
- if (IS_ERR(tty_dev)) {
- ret = PTR_ERR(tty_dev);
- goto register_fail;
- }
ret = kfifo_alloc(&port->write_fifo, DBC_WRITE_BUF_SIZE, GFP_KERNEL);
if (ret)
- goto buf_alloc_fail;
+ goto err_exit_port;
ret = xhci_dbc_alloc_requests(dbc, BULK_IN, &port->read_pool,
dbc_read_complete);
if (ret)
- goto request_fail;
+ goto err_free_fifo;
ret = xhci_dbc_alloc_requests(dbc, BULK_OUT, &port->write_pool,
dbc_write_complete);
if (ret)
- goto request_fail;
+ goto err_free_requests;
+
+ tty_dev = tty_port_register_device(&port->port,
+ dbc_tty_driver, 0, NULL);
+ if (IS_ERR(tty_dev)) {
+ ret = PTR_ERR(tty_dev);
+ goto err_free_requests;
+ }
port->registered = true;
return 0;
-request_fail:
+err_free_requests:
xhci_dbc_free_requests(&port->read_pool);
xhci_dbc_free_requests(&port->write_pool);
+err_free_fifo:
kfifo_free(&port->write_fifo);
-
-buf_alloc_fail:
- tty_unregister_device(dbc_tty_driver, 0);
-
-register_fail:
+err_exit_port:
xhci_dbc_tty_exit_port(port);
dev_err(dbc->dev, "can't register tty port, err %d\n", ret);
--
2.32.0
next reply other threads:[~2021-09-28 12:05 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-28 12:04 Johan Hovold [this message]
2021-09-30 9:24 ` [PATCH] USB: xhci: dbc: fix tty registration race Mathias Nyman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210928120400.20704-1-johan@kernel.org \
--to=johan@kernel.org \
--cc=baolu.lu@linux.intel.com \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=mathias.nyman@intel.com \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).