From: Xie He <xie.he.0141@gmail.com>
To: "David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>,
Xie He <xie.he.0141@gmail.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-x25@vger.kernel.org
Subject: [PATCH] drivers/net/wan/lapbether: Fixed the value of hard_header_len
Date: Fri, 3 Jul 2020 22:12:46 -0700 [thread overview]
Message-ID: <20200704051246.203413-1-xie.he.0141@gmail.com> (raw)
When transmitting data from upper layers or from AF_PACKET sockets,
this driver will first remove a pseudo header of 1 byte,
then the lapb module will prepend the LAPB header of 2 or 3 bytes,
then this driver will prepend a length field of 2 bytes,
then the underlying Ethernet device will prepend its own header.
So, the header length required should be:
-1 + 3 + 2 + "the header length needed by the underlying device".
This patch fixes kernel panic when this driver is used with AF_PACKET
SOCK_DGRAM sockets.
Signed-off-by: Xie He <xie.he.0141@gmail.com>
---
drivers/net/wan/lapbether.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wan/lapbether.c b/drivers/net/wan/lapbether.c
index e30d91a38cfb..3b5ed0928a4c 100644
--- a/drivers/net/wan/lapbether.c
+++ b/drivers/net/wan/lapbether.c
@@ -303,7 +303,6 @@ static void lapbeth_setup(struct net_device *dev)
dev->netdev_ops = &lapbeth_netdev_ops;
dev->needs_free_netdev = true;
dev->type = ARPHRD_X25;
- dev->hard_header_len = 3;
dev->mtu = 1000;
dev->addr_len = 0;
}
@@ -324,6 +323,8 @@ static int lapbeth_new_device(struct net_device *dev)
if (!ndev)
goto out;
+ ndev->hard_header_len = -1 + 3 + 2 + dev->hard_header_len;
+
lapbeth = netdev_priv(ndev);
lapbeth->axdev = ndev;
--
2.25.1
next reply other threads:[~2020-07-04 5:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-04 5:12 Xie He [this message]
2020-07-05 0:52 ` [PATCH] drivers/net/wan/lapbether: Fixed the value of hard_header_len David Miller
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=20200704051246.203413-1-xie.he.0141@gmail.com \
--to=xie.he.0141@gmail.com \
--cc=davem@davemloft.net \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-x25@vger.kernel.org \
--cc=madhuparnabhowmik04@gmail.com \
--cc=netdev@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 read-only IMAP folder(s) and NNTP newsgroup(s).