<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/net, branch v4.9.296</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>fsl/fman: Fix missing put_device() call in fman_port_probe</title>
<updated>2022-01-05T11:31:24+00:00</updated>
<author>
<name>Miaoqian Lin</name>
<email>linmq006@gmail.com</email>
</author>
<published>2021-12-30T12:26:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=35174d1179853a6908d10395ace888b0d189c71e'/>
<id>35174d1179853a6908d10395ace888b0d189c71e</id>
<content type='text'>
[ Upstream commit bf2b09fedc17248b315f80fb249087b7d28a69a6 ]

The reference taken by 'of_find_device_by_node()' must be released when
not needed anymore.
Add the corresponding 'put_device()' in the and error handling paths.

Fixes: 18a6c85fcc78 ("fsl/fman: Add FMan Port Support")
Signed-off-by: Miaoqian Lin &lt;linmq006@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit bf2b09fedc17248b315f80fb249087b7d28a69a6 ]

The reference taken by 'of_find_device_by_node()' must be released when
not needed anymore.
Add the corresponding 'put_device()' in the and error handling paths.

Fixes: 18a6c85fcc78 ("fsl/fman: Add FMan Port Support")
Signed-off-by: Miaoqian Lin &lt;linmq006@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>hamradio: improve the incomplete fix to avoid NPD</title>
<updated>2021-12-29T11:14:49+00:00</updated>
<author>
<name>Lin Ma</name>
<email>linma@zju.edu.cn</email>
</author>
<published>2021-12-17T02:13:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=83ba6ec97c74fb1a60f7779a26b6a94b28741d8a'/>
<id>83ba6ec97c74fb1a60f7779a26b6a94b28741d8a</id>
<content type='text'>
commit b2f37aead1b82a770c48b5d583f35ec22aabb61e upstream.

The previous commit 3e0588c291d6 ("hamradio: defer ax25 kfree after
unregister_netdev") reorder the kfree operations and unregister_netdev
operation to prevent UAF.

This commit improves the previous one by also deferring the nullify of
the ax-&gt;tty pointer. Otherwise, a NULL pointer dereference bug occurs.
Partial of the stack trace is shown below.

BUG: kernel NULL pointer dereference, address: 0000000000000538
RIP: 0010:ax_xmit+0x1f9/0x400
...
Call Trace:
 dev_hard_start_xmit+0xec/0x320
 sch_direct_xmit+0xea/0x240
 __qdisc_run+0x166/0x5c0
 __dev_queue_xmit+0x2c7/0xaf0
 ax25_std_establish_data_link+0x59/0x60
 ax25_connect+0x3a0/0x500
 ? security_socket_connect+0x2b/0x40
 __sys_connect+0x96/0xc0
 ? __hrtimer_init+0xc0/0xc0
 ? common_nsleep+0x2e/0x50
 ? switch_fpu_return+0x139/0x1a0
 __x64_sys_connect+0x11/0x20
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The crash point is shown as below

static void ax_encaps(...) {
  ...
  set_bit(TTY_DO_WRITE_WAKEUP, &amp;ax-&gt;tty-&gt;flags); // ax-&gt;tty = NULL!
  ...
}

By placing the nullify action after the unregister_netdev, the ax-&gt;tty
pointer won't be assigned as NULL net_device framework layer is well
synchronized.

Signed-off-by: Lin Ma &lt;linma@zju.edu.cn&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit b2f37aead1b82a770c48b5d583f35ec22aabb61e upstream.

The previous commit 3e0588c291d6 ("hamradio: defer ax25 kfree after
unregister_netdev") reorder the kfree operations and unregister_netdev
operation to prevent UAF.

This commit improves the previous one by also deferring the nullify of
the ax-&gt;tty pointer. Otherwise, a NULL pointer dereference bug occurs.
Partial of the stack trace is shown below.

BUG: kernel NULL pointer dereference, address: 0000000000000538
RIP: 0010:ax_xmit+0x1f9/0x400
...
Call Trace:
 dev_hard_start_xmit+0xec/0x320
 sch_direct_xmit+0xea/0x240
 __qdisc_run+0x166/0x5c0
 __dev_queue_xmit+0x2c7/0xaf0
 ax25_std_establish_data_link+0x59/0x60
 ax25_connect+0x3a0/0x500
 ? security_socket_connect+0x2b/0x40
 __sys_connect+0x96/0xc0
 ? __hrtimer_init+0xc0/0xc0
 ? common_nsleep+0x2e/0x50
 ? switch_fpu_return+0x139/0x1a0
 __x64_sys_connect+0x11/0x20
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The crash point is shown as below

static void ax_encaps(...) {
  ...
  set_bit(TTY_DO_WRITE_WAKEUP, &amp;ax-&gt;tty-&gt;flags); // ax-&gt;tty = NULL!
  ...
}

By placing the nullify action after the unregister_netdev, the ax-&gt;tty
pointer won't be assigned as NULL net_device framework layer is well
synchronized.

Signed-off-by: Lin Ma &lt;linma@zju.edu.cn&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>hamradio: defer ax25 kfree after unregister_netdev</title>
<updated>2021-12-29T11:14:49+00:00</updated>
<author>
<name>Lin Ma</name>
<email>linma@zju.edu.cn</email>
</author>
<published>2021-11-08T10:37:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8a1a314965a17c62084a056b4f2cb7a770854c90'/>
<id>8a1a314965a17c62084a056b4f2cb7a770854c90</id>
<content type='text'>
commit 3e0588c291d6ce225f2b891753ca41d45ba42469 upstream.

There is a possible race condition (use-after-free) like below

 (USE)                       |  (FREE)
ax25_sendmsg                 |
 ax25_queue_xmit             |
  dev_queue_xmit             |
   __dev_queue_xmit          |
    __dev_xmit_skb           |
     sch_direct_xmit         | ...
      xmit_one               |
       netdev_start_xmit     | tty_ldisc_kill
        __netdev_start_xmit  |  mkiss_close
         ax_xmit             |   kfree
          ax_encaps          |
                             |

Even though there are two synchronization primitives before the kfree:
1. wait_for_completion(&amp;ax-&gt;dead). This can prevent the race with
routines from mkiss_ioctl. However, it cannot stop the routine coming
from upper layer, i.e., the ax25_sendmsg.

2. netif_stop_queue(ax-&gt;dev). It seems that this line of code aims to
halt the transmit queue but it fails to stop the routine that already
being xmit.

This patch reorder the kfree after the unregister_netdev to avoid the
possible UAF as the unregister_netdev() is well synchronized and won't
return if there is a running routine.

Signed-off-by: Lin Ma &lt;linma@zju.edu.cn&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 3e0588c291d6ce225f2b891753ca41d45ba42469 upstream.

There is a possible race condition (use-after-free) like below

 (USE)                       |  (FREE)
ax25_sendmsg                 |
 ax25_queue_xmit             |
  dev_queue_xmit             |
   __dev_queue_xmit          |
    __dev_xmit_skb           |
     sch_direct_xmit         | ...
      xmit_one               |
       netdev_start_xmit     | tty_ldisc_kill
        __netdev_start_xmit  |  mkiss_close
         ax_xmit             |   kfree
          ax_encaps          |
                             |

Even though there are two synchronization primitives before the kfree:
1. wait_for_completion(&amp;ax-&gt;dead). This can prevent the race with
routines from mkiss_ioctl. However, it cannot stop the routine coming
from upper layer, i.e., the ax25_sendmsg.

2. netif_stop_queue(ax-&gt;dev). It seems that this line of code aims to
halt the transmit queue but it fails to stop the routine that already
being xmit.

This patch reorder the kfree after the unregister_netdev to avoid the
possible UAF as the unregister_netdev() is well synchronized and won't
return if there is a running routine.

Signed-off-by: Lin Ma &lt;linma@zju.edu.cn&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drivers: net: smc911x: Check for error irq</title>
<updated>2021-12-29T11:14:48+00:00</updated>
<author>
<name>Jiasheng Jiang</name>
<email>jiasheng@iscas.ac.cn</email>
</author>
<published>2021-12-22T07:41:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6317d86491e650dd5076051dbb51523ee615e6dd'/>
<id>6317d86491e650dd5076051dbb51523ee615e6dd</id>
<content type='text'>
[ Upstream commit cb93b3e11d405f20a405a07482d01147ef4934a3 ]

Because platform_get_irq() could fail and return error irq.
Therefore, it might be better to check it if order to avoid the use of
error irq.

Fixes: ae150435b59e ("smsc: Move the SMC (SMSC) drivers")
Signed-off-by: Jiasheng Jiang &lt;jiasheng@iscas.ac.cn&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit cb93b3e11d405f20a405a07482d01147ef4934a3 ]

Because platform_get_irq() could fail and return error irq.
Therefore, it might be better to check it if order to avoid the use of
error irq.

Fixes: ae150435b59e ("smsc: Move the SMC (SMSC) drivers")
Signed-off-by: Jiasheng Jiang &lt;jiasheng@iscas.ac.cn&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fjes: Check for error irq</title>
<updated>2021-12-29T11:14:48+00:00</updated>
<author>
<name>Jiasheng Jiang</name>
<email>jiasheng@iscas.ac.cn</email>
</author>
<published>2021-12-22T07:12:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fb3189a2a49b20e0619a3551d1b541fe66f937fd'/>
<id>fb3189a2a49b20e0619a3551d1b541fe66f937fd</id>
<content type='text'>
[ Upstream commit db6d6afe382de5a65d6ccf51253ab48b8e8336c3 ]

I find that platform_get_irq() will not always succeed.
It will return error irq in case of the failure.
Therefore, it might be better to check it if order to avoid the use of
error irq.

Fixes: 658d439b2292 ("fjes: Introduce FUJITSU Extended Socket Network Device driver")
Signed-off-by: Jiasheng Jiang &lt;jiasheng@iscas.ac.cn&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit db6d6afe382de5a65d6ccf51253ab48b8e8336c3 ]

I find that platform_get_irq() will not always succeed.
It will return error irq in case of the failure.
Therefore, it might be better to check it if order to avoid the use of
error irq.

Fixes: 658d439b2292 ("fjes: Introduce FUJITSU Extended Socket Network Device driver")
Signed-off-by: Jiasheng Jiang &lt;jiasheng@iscas.ac.cn&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bonding: fix ad_actor_system option setting to default</title>
<updated>2021-12-29T11:14:48+00:00</updated>
<author>
<name>Fernando Fernandez Mancera</name>
<email>ffmancera@riseup.net</email>
</author>
<published>2021-12-21T11:13:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=53cf468483ae87aa1d9b46a2df3cd88cb08459fb'/>
<id>53cf468483ae87aa1d9b46a2df3cd88cb08459fb</id>
<content type='text'>
[ Upstream commit 1c15b05baea71a5ff98235783e3e4ad227760876 ]

When 802.3ad bond mode is configured the ad_actor_system option is set to
"00:00:00:00:00:00". But when trying to set the all-zeroes MAC as actors'
system address it was failing with EINVAL.

An all-zeroes ethernet address is valid, only multicast addresses are not
valid values.

Fixes: 171a42c38c6e ("bonding: add netlink support for sys prio, actor sys mac, and port key")
Signed-off-by: Fernando Fernandez Mancera &lt;ffmancera@riseup.net&gt;
Acked-by: Jay Vosburgh &lt;jay.vosburgh@canonical.com&gt;
Link: https://lore.kernel.org/r/20211221111345.2462-1-ffmancera@riseup.net
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 1c15b05baea71a5ff98235783e3e4ad227760876 ]

When 802.3ad bond mode is configured the ad_actor_system option is set to
"00:00:00:00:00:00". But when trying to set the all-zeroes MAC as actors'
system address it was failing with EINVAL.

An all-zeroes ethernet address is valid, only multicast addresses are not
valid values.

Fixes: 171a42c38c6e ("bonding: add netlink support for sys prio, actor sys mac, and port key")
Signed-off-by: Fernando Fernandez Mancera &lt;ffmancera@riseup.net&gt;
Acked-by: Jay Vosburgh &lt;jay.vosburgh@canonical.com&gt;
Link: https://lore.kernel.org/r/20211221111345.2462-1-ffmancera@riseup.net
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>qlcnic: potential dereference null pointer of rx_queue-&gt;page_ring</title>
<updated>2021-12-29T11:14:48+00:00</updated>
<author>
<name>Jiasheng Jiang</name>
<email>jiasheng@iscas.ac.cn</email>
</author>
<published>2021-12-17T09:39:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d4504fead12e19d34bcc5dd8823505ec3ea11466'/>
<id>d4504fead12e19d34bcc5dd8823505ec3ea11466</id>
<content type='text'>
[ Upstream commit 60ec7fcfe76892a1479afab51ff17a4281923156 ]

The return value of kcalloc() needs to be checked.
To avoid dereference of null pointer in case of the failure of alloc.
Therefore, it might be better to change the return type of
qlcnic_sriov_alloc_vlans() and return -ENOMEM when alloc fails and
return 0 the others.
Also, qlcnic_sriov_set_guest_vlan_mode() and __qlcnic_pci_sriov_enable()
should deal with the return value of qlcnic_sriov_alloc_vlans().

Fixes: 154d0c810c53 ("qlcnic: VLAN enhancement for 84XX adapters")
Signed-off-by: Jiasheng Jiang &lt;jiasheng@iscas.ac.cn&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 60ec7fcfe76892a1479afab51ff17a4281923156 ]

The return value of kcalloc() needs to be checked.
To avoid dereference of null pointer in case of the failure of alloc.
Therefore, it might be better to change the return type of
qlcnic_sriov_alloc_vlans() and return -ENOMEM when alloc fails and
return 0 the others.
Also, qlcnic_sriov_set_guest_vlan_mode() and __qlcnic_pci_sriov_enable()
should deal with the return value of qlcnic_sriov_alloc_vlans().

Fixes: 154d0c810c53 ("qlcnic: VLAN enhancement for 84XX adapters")
Signed-off-by: Jiasheng Jiang &lt;jiasheng@iscas.ac.cn&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>can: kvaser_usb: get CAN clock frequency from device</title>
<updated>2021-12-29T11:14:48+00:00</updated>
<author>
<name>Jimmy Assarsson</name>
<email>extja@kvaser.com</email>
</author>
<published>2021-12-08T15:21:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2e663a0776edeaf413aaf9adf21c9d013c9512a1'/>
<id>2e663a0776edeaf413aaf9adf21c9d013c9512a1</id>
<content type='text'>
commit fb12797ab1fef480ad8a32a30984844444eeb00d upstream.

The CAN clock frequency is used when calculating the CAN bittiming
parameters. When wrong clock frequency is used, the device may end up
with wrong bittiming parameters, depending on user requested bittiming
parameters.

To avoid this, get the CAN clock frequency from the device. Various
existing Kvaser Leaf products use different CAN clocks.

Fixes: 080f40a6fa28 ("can: kvaser_usb: Add support for Kvaser CAN/USB devices")
Link: https://lore.kernel.org/all/20211208152122.250852-2-extja@kvaser.com
Cc: stable@vger.kernel.org
Signed-off-by: Jimmy Assarsson &lt;extja@kvaser.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit fb12797ab1fef480ad8a32a30984844444eeb00d upstream.

The CAN clock frequency is used when calculating the CAN bittiming
parameters. When wrong clock frequency is used, the device may end up
with wrong bittiming parameters, depending on user requested bittiming
parameters.

To avoid this, get the CAN clock frequency from the device. Various
existing Kvaser Leaf products use different CAN clocks.

Fixes: 080f40a6fa28 ("can: kvaser_usb: Add support for Kvaser CAN/USB devices")
Link: https://lore.kernel.org/all/20211208152122.250852-2-extja@kvaser.com
Cc: stable@vger.kernel.org
Signed-off-by: Jimmy Assarsson &lt;extja@kvaser.com&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: usb: lan78xx: add Allied Telesis AT29M2-AF</title>
<updated>2021-12-29T11:14:48+00:00</updated>
<author>
<name>Greg Jesionowski</name>
<email>jesionowskigreg@gmail.com</email>
</author>
<published>2021-12-14T22:10:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2c0458f9f596b9674b5522406b6d29b101d3561a'/>
<id>2c0458f9f596b9674b5522406b6d29b101d3561a</id>
<content type='text'>
commit ef8a0f6eab1ca5d1a75c242c5c7b9d386735fa0a upstream.

This adds the vendor and product IDs for the AT29M2-AF which is a
lan7801-based device.

Signed-off-by: Greg Jesionowski &lt;jesionowskigreg@gmail.com&gt;
Link: https://lore.kernel.org/r/20211214221027.305784-1-jesionowskigreg@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit ef8a0f6eab1ca5d1a75c242c5c7b9d386735fa0a upstream.

This adds the vendor and product IDs for the AT29M2-AF which is a
lan7801-based device.

Signed-off-by: Greg Jesionowski &lt;jesionowskigreg@gmail.com&gt;
Link: https://lore.kernel.org/r/20211214221027.305784-1-jesionowskigreg@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xen/netback: don't queue unlimited number of packages</title>
<updated>2021-12-22T08:05:16+00:00</updated>
<author>
<name>Juergen Gross</name>
<email>jgross@suse.com</email>
</author>
<published>2021-11-30T07:36:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b4226b387436315e7f57465c15335f4f4b5b075d'/>
<id>b4226b387436315e7f57465c15335f4f4b5b075d</id>
<content type='text'>
commit be81992f9086b230623ae3ebbc85ecee4d00a3d3 upstream.

In case a guest isn't consuming incoming network traffic as fast as it
is coming in, xen-netback is buffering network packages in unlimited
numbers today. This can result in host OOM situations.

Commit f48da8b14d04ca8 ("xen-netback: fix unlimited guest Rx internal
queue and carrier flapping") meant to introduce a mechanism to limit
the amount of buffered data by stopping the Tx queue when reaching the
data limit, but this doesn't work for cases like UDP.

When hitting the limit don't queue further SKBs, but drop them instead.
In order to be able to tell Rx packages have been dropped increment the
rx_dropped statistics counter in this case.

It should be noted that the old solution to continue queueing SKBs had
the additional problem of an overflow of the 32-bit rx_queue_len value
would result in intermittent Tx queue enabling.

This is part of XSA-392

Fixes: f48da8b14d04ca8 ("xen-netback: fix unlimited guest Rx internal queue and carrier flapping")
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Reviewed-by: Jan Beulich &lt;jbeulich@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
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<pre>
commit be81992f9086b230623ae3ebbc85ecee4d00a3d3 upstream.

In case a guest isn't consuming incoming network traffic as fast as it
is coming in, xen-netback is buffering network packages in unlimited
numbers today. This can result in host OOM situations.

Commit f48da8b14d04ca8 ("xen-netback: fix unlimited guest Rx internal
queue and carrier flapping") meant to introduce a mechanism to limit
the amount of buffered data by stopping the Tx queue when reaching the
data limit, but this doesn't work for cases like UDP.

When hitting the limit don't queue further SKBs, but drop them instead.
In order to be able to tell Rx packages have been dropped increment the
rx_dropped statistics counter in this case.

It should be noted that the old solution to continue queueing SKBs had
the additional problem of an overflow of the 32-bit rx_queue_len value
would result in intermittent Tx queue enabling.

This is part of XSA-392

Fixes: f48da8b14d04ca8 ("xen-netback: fix unlimited guest Rx internal queue and carrier flapping")
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Reviewed-by: Jan Beulich &lt;jbeulich@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
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