<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/drivers/net/dsa, branch v6.0-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>net: mscc: ocelot: keep ocelot_stat_layout by reg address, not offset</title>
<updated>2022-08-18T04:58:32+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2022-08-16T13:53:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=d4c367650704de091d4c1f6bb379c0a5c389c73a'/>
<id>d4c367650704de091d4c1f6bb379c0a5c389c73a</id>
<content type='text'>
With so many counter addresses recently discovered as being wrong, it is
desirable to at least have a central database of information, rather
than two: one through the SYS_COUNT_* registers (used for
ndo_get_stats64), and the other through the offset field of struct
ocelot_stat_layout elements (used for ethtool -S).

The strategy will be to keep the SYS_COUNT_* definitions as the single
source of truth, but for that we need to expand our current definitions
to cover all registers. Then we need to convert the ocelot region
creation logic, and stats worker, to the read semantics imposed by going
through SYS_COUNT_* absolute register addresses, rather than offsets
of 32-bit words relative to SYS_COUNT_RX_OCTETS (which should have been
SYS_CNT, by the way).

Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
With so many counter addresses recently discovered as being wrong, it is
desirable to at least have a central database of information, rather
than two: one through the SYS_COUNT_* registers (used for
ndo_get_stats64), and the other through the offset field of struct
ocelot_stat_layout elements (used for ethtool -S).

The strategy will be to keep the SYS_COUNT_* definitions as the single
source of truth, but for that we need to expand our current definitions
to cover all registers. Then we need to convert the ocelot region
creation logic, and stats worker, to the read semantics imposed by going
through SYS_COUNT_* absolute register addresses, rather than offsets
of 32-bit words relative to SYS_COUNT_RX_OCTETS (which should have been
SYS_CNT, by the way).

Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: mscc: ocelot: make struct ocelot_stat_layout array indexable</title>
<updated>2022-08-18T04:58:32+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2022-08-16T13:53:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=9190460084ddd0e9235f55eab0fdd5456b5f2fd5'/>
<id>9190460084ddd0e9235f55eab0fdd5456b5f2fd5</id>
<content type='text'>
The ocelot counters are 32-bit and require periodic reading, every 2
seconds, by ocelot_port_update_stats(), so that wraparounds are
detected.

Currently, the counters reported by ocelot_get_stats64() come from the
32-bit hardware counters directly, rather than from the 64-bit
accumulated ocelot-&gt;stats, and this is a problem for their integrity.

The strategy is to make ocelot_get_stats64() able to cherry-pick
individual stats from ocelot-&gt;stats the way in which it currently reads
them out from SYS_COUNT_* registers. But currently it can't, because
ocelot-&gt;stats is an opaque u64 array that's used only to feed data into
ethtool -S.

To solve that problem, we need to make ocelot-&gt;stats indexable, and
associate each element with an element of struct ocelot_stat_layout used
by ethtool -S.

This makes ocelot_stat_layout a fat (and possibly sparse) array, so we
need to change the way in which we access it. We no longer need
OCELOT_STAT_END as a sentinel, because we know the array's size
(OCELOT_NUM_STATS). We just need to skip the array elements that were
left unpopulated for the switch revision (ocelot, felix, seville).

Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The ocelot counters are 32-bit and require periodic reading, every 2
seconds, by ocelot_port_update_stats(), so that wraparounds are
detected.

Currently, the counters reported by ocelot_get_stats64() come from the
32-bit hardware counters directly, rather than from the 64-bit
accumulated ocelot-&gt;stats, and this is a problem for their integrity.

The strategy is to make ocelot_get_stats64() able to cherry-pick
individual stats from ocelot-&gt;stats the way in which it currently reads
them out from SYS_COUNT_* registers. But currently it can't, because
ocelot-&gt;stats is an opaque u64 array that's used only to feed data into
ethtool -S.

To solve that problem, we need to make ocelot-&gt;stats indexable, and
associate each element with an element of struct ocelot_stat_layout used
by ethtool -S.

This makes ocelot_stat_layout a fat (and possibly sparse) array, so we
need to change the way in which we access it. We no longer need
OCELOT_STAT_END as a sentinel, because we know the array's size
(OCELOT_NUM_STATS). We just need to skip the array elements that were
left unpopulated for the switch revision (ocelot, felix, seville).

Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: mscc: ocelot: turn stats_lock into a spinlock</title>
<updated>2022-08-18T04:58:31+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2022-08-16T13:53:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=22d842e3efe56402c33b5e6e303bb71ce9bf9334'/>
<id>22d842e3efe56402c33b5e6e303bb71ce9bf9334</id>
<content type='text'>
ocelot_get_stats64() currently runs unlocked and therefore may collide
with ocelot_port_update_stats() which indirectly accesses the same
counters. However, ocelot_get_stats64() runs in atomic context, and we
cannot simply take the sleepable ocelot-&gt;stats_lock mutex. We need to
convert it to an atomic spinlock first. Do that as a preparatory change.

Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
ocelot_get_stats64() currently runs unlocked and therefore may collide
with ocelot_port_update_stats() which indirectly accesses the same
counters. However, ocelot_get_stats64() runs in atomic context, and we
cannot simply take the sleepable ocelot-&gt;stats_lock mutex. We need to
convert it to an atomic spinlock first. Do that as a preparatory change.

Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: mscc: ocelot: fix incorrect ndo_get_stats64 packet counters</title>
<updated>2022-08-18T04:58:30+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2022-08-16T13:53:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=5152de7b79ab0be150f5966481b0c8f996192531'/>
<id>5152de7b79ab0be150f5966481b0c8f996192531</id>
<content type='text'>
Reading stats using the SYS_COUNT_* register definitions is only used by
ocelot_get_stats64() from the ocelot switchdev driver, however,
currently the bucket definitions are incorrect.

Separately, on both RX and TX, we have the following problems:
- a 256-1023 bucket which actually tracks the 256-511 packets
- the 1024-1526 bucket actually tracks the 512-1023 packets
- the 1527-max bucket actually tracks the 1024-1526 packets

=&gt; nobody tracks the packets from the real 1527-max bucket

Additionally, the RX_PAUSE, RX_CONTROL, RX_LONGS and RX_CLASSIFIED_DROPS
all track the wrong thing. However this doesn't seem to have any
consequence, since ocelot_get_stats64() doesn't use these.

Even though this problem only manifests itself for the switchdev driver,
we cannot split the fix for ocelot and for DSA, since it requires fixing
the bucket definitions from enum ocelot_reg, which makes us necessarily
adapt the structures from felix and seville as well.

Fixes: 84705fc16552 ("net: dsa: felix: introduce support for Seville VSC9953 switch")
Fixes: 56051948773e ("net: dsa: ocelot: add driver for Felix switch family")
Fixes: a556c76adc05 ("net: mscc: Add initial Ocelot switch support")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Reading stats using the SYS_COUNT_* register definitions is only used by
ocelot_get_stats64() from the ocelot switchdev driver, however,
currently the bucket definitions are incorrect.

Separately, on both RX and TX, we have the following problems:
- a 256-1023 bucket which actually tracks the 256-511 packets
- the 1024-1526 bucket actually tracks the 512-1023 packets
- the 1527-max bucket actually tracks the 1024-1526 packets

=&gt; nobody tracks the packets from the real 1527-max bucket

Additionally, the RX_PAUSE, RX_CONTROL, RX_LONGS and RX_CLASSIFIED_DROPS
all track the wrong thing. However this doesn't seem to have any
consequence, since ocelot_get_stats64() doesn't use these.

Even though this problem only manifests itself for the switchdev driver,
we cannot split the fix for ocelot and for DSA, since it requires fixing
the bucket definitions from enum ocelot_reg, which makes us necessarily
adapt the structures from felix and seville as well.

Fixes: 84705fc16552 ("net: dsa: felix: introduce support for Seville VSC9953 switch")
Fixes: 56051948773e ("net: dsa: ocelot: add driver for Felix switch family")
Fixes: a556c76adc05 ("net: mscc: Add initial Ocelot switch support")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dsa: felix: fix ethtool 256-511 and 512-1023 TX packet counters</title>
<updated>2022-08-18T04:58:30+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2022-08-16T13:53:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=40d21c4565bce064c73a03b79a157a3493c518b9'/>
<id>40d21c4565bce064c73a03b79a157a3493c518b9</id>
<content type='text'>
What the driver actually reports as 256-511 is in fact 512-1023, and the
TX packets in the 256-511 bucket are not reported. Fix that.

Fixes: 56051948773e ("net: dsa: ocelot: add driver for Felix switch family")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
What the driver actually reports as 256-511 is in fact 512-1023, and the
TX packets in the 256-511 bucket are not reported. Fix that.

Fixes: 56051948773e ("net: dsa: ocelot: add driver for Felix switch family")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dsa: sja1105: fix buffer overflow in sja1105_setup_devlink_regions()</title>
<updated>2022-08-18T04:58:15+00:00</updated>
<author>
<name>Rustam Subkhankulov</name>
<email>subkhankulov@ispras.ru</email>
</author>
<published>2022-08-17T00:38:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=fd8e899cdb5ecaf8e8ee73854a99e10807eef1de'/>
<id>fd8e899cdb5ecaf8e8ee73854a99e10807eef1de</id>
<content type='text'>
If an error occurs in dsa_devlink_region_create(), then 'priv-&gt;regions'
array will be accessed by negative index '-1'.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Rustam Subkhankulov &lt;subkhankulov@ispras.ru&gt;
Fixes: bf425b82059e ("net: dsa: sja1105: expose static config as devlink region")
Link: https://lore.kernel.org/r/20220817003845.389644-1-subkhankulov@ispras.ru
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
If an error occurs in dsa_devlink_region_create(), then 'priv-&gt;regions'
array will be accessed by negative index '-1'.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Rustam Subkhankulov &lt;subkhankulov@ispras.ru&gt;
Fixes: bf425b82059e ("net: dsa: sja1105: expose static config as devlink region")
Link: https://lore.kernel.org/r/20220817003845.389644-1-subkhankulov@ispras.ru
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dsa: microchip: ksz9477: fix fdb_dump last invalid entry</title>
<updated>2022-08-17T19:09:01+00:00</updated>
<author>
<name>Arun Ramadoss</name>
<email>arun.ramadoss@microchip.com</email>
</author>
<published>2022-08-16T10:55:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=36c0d935015766bf20d621c18313f17691bda5e3'/>
<id>36c0d935015766bf20d621c18313f17691bda5e3</id>
<content type='text'>
In the ksz9477_fdb_dump function it reads the ALU control register and
exit from the timeout loop if there is valid entry or search is
complete. After exiting the loop, it reads the alu entry and report to
the user space irrespective of entry is valid. It works till the valid
entry. If the loop exited when search is complete, it reads the alu
table. The table returns all ones and it is reported to user space. So
bridge fdb show gives ff:ff:ff:ff:ff:ff as last entry for every port.
To fix it, after exiting the loop the entry is reported only if it is
valid one.

Fixes: b987e98e50ab ("dsa: add DSA switch driver for Microchip KSZ9477")
Signed-off-by: Arun Ramadoss &lt;arun.ramadoss@microchip.com&gt;
Reviewed-by: Vladimir Oltean &lt;olteanv@gmail.com&gt;
Link: https://lore.kernel.org/r/20220816105516.18350-1-arun.ramadoss@microchip.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In the ksz9477_fdb_dump function it reads the ALU control register and
exit from the timeout loop if there is valid entry or search is
complete. After exiting the loop, it reads the alu entry and report to
the user space irrespective of entry is valid. It works till the valid
entry. If the loop exited when search is complete, it reads the alu
table. The table returns all ones and it is reported to user space. So
bridge fdb show gives ff:ff:ff:ff:ff:ff as last entry for every port.
To fix it, after exiting the loop the entry is reported only if it is
valid one.

Fixes: b987e98e50ab ("dsa: add DSA switch driver for Microchip KSZ9477")
Signed-off-by: Arun Ramadoss &lt;arun.ramadoss@microchip.com&gt;
Reviewed-by: Vladimir Oltean &lt;olteanv@gmail.com&gt;
Link: https://lore.kernel.org/r/20220816105516.18350-1-arun.ramadoss@microchip.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dsa: mv88e6060: prevent crash on an unused port</title>
<updated>2022-08-13T00:24:44+00:00</updated>
<author>
<name>Sergei Antonov</name>
<email>saproj@gmail.com</email>
</author>
<published>2022-08-11T07:09:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=246bbf2f977ea36aaf41f5d24370fef433250728'/>
<id>246bbf2f977ea36aaf41f5d24370fef433250728</id>
<content type='text'>
If the port isn't a CPU port nor a user port, 'cpu_dp'
is a null pointer and a crash happened on dereferencing
it in mv88e6060_setup_port():

[    9.575872] Unable to handle kernel NULL pointer dereference at virtual address 00000014
...
[    9.942216]  mv88e6060_setup from dsa_register_switch+0x814/0xe84
[    9.948616]  dsa_register_switch from mdio_probe+0x2c/0x54
[    9.954433]  mdio_probe from really_probe.part.0+0x98/0x2a0
[    9.960375]  really_probe.part.0 from driver_probe_device+0x30/0x10c
[    9.967029]  driver_probe_device from __device_attach_driver+0xb8/0x13c
[    9.973946]  __device_attach_driver from bus_for_each_drv+0x90/0xe0
[    9.980509]  bus_for_each_drv from __device_attach+0x110/0x184
[    9.986632]  __device_attach from bus_probe_device+0x8c/0x94
[    9.992577]  bus_probe_device from deferred_probe_work_func+0x78/0xa8
[    9.999311]  deferred_probe_work_func from process_one_work+0x290/0x73c
[   10.006292]  process_one_work from worker_thread+0x30/0x4b8
[   10.012155]  worker_thread from kthread+0xd4/0x10c
[   10.017238]  kthread from ret_from_fork+0x14/0x3c

Fixes: 0abfd494deef ("net: dsa: use dedicated CPU port")
CC: Vivien Didelot &lt;vivien.didelot@savoirfairelinux.com&gt;
CC: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Signed-off-by: Sergei Antonov &lt;saproj@gmail.com&gt;
Signed-off-by: Vladimir Oltean &lt;olteanv@gmail.com&gt;
Link: https://lore.kernel.org/r/20220811070939.1717146-1-saproj@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
If the port isn't a CPU port nor a user port, 'cpu_dp'
is a null pointer and a crash happened on dereferencing
it in mv88e6060_setup_port():

[    9.575872] Unable to handle kernel NULL pointer dereference at virtual address 00000014
...
[    9.942216]  mv88e6060_setup from dsa_register_switch+0x814/0xe84
[    9.948616]  dsa_register_switch from mdio_probe+0x2c/0x54
[    9.954433]  mdio_probe from really_probe.part.0+0x98/0x2a0
[    9.960375]  really_probe.part.0 from driver_probe_device+0x30/0x10c
[    9.967029]  driver_probe_device from __device_attach_driver+0xb8/0x13c
[    9.973946]  __device_attach_driver from bus_for_each_drv+0x90/0xe0
[    9.980509]  bus_for_each_drv from __device_attach+0x110/0x184
[    9.986632]  __device_attach from bus_probe_device+0x8c/0x94
[    9.992577]  bus_probe_device from deferred_probe_work_func+0x78/0xa8
[    9.999311]  deferred_probe_work_func from process_one_work+0x290/0x73c
[   10.006292]  process_one_work from worker_thread+0x30/0x4b8
[   10.012155]  worker_thread from kthread+0xd4/0x10c
[   10.017238]  kthread from ret_from_fork+0x14/0x3c

Fixes: 0abfd494deef ("net: dsa: use dedicated CPU port")
CC: Vivien Didelot &lt;vivien.didelot@savoirfairelinux.com&gt;
CC: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Signed-off-by: Sergei Antonov &lt;saproj@gmail.com&gt;
Signed-off-by: Vladimir Oltean &lt;olteanv@gmail.com&gt;
Link: https://lore.kernel.org/r/20220811070939.1717146-1-saproj@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dsa: felix: suppress non-changes to the tagging protocol</title>
<updated>2022-08-09T19:13:03+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2022-08-08T12:51:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=4c46bb49460ee14c69629e813640d8b929e88941'/>
<id>4c46bb49460ee14c69629e813640d8b929e88941</id>
<content type='text'>
The way in which dsa_tree_change_tag_proto() works is that when
dsa_tree_notify() fails, it doesn't know whether the operation failed
mid way in a multi-switch tree, or it failed for a single-switch tree.
So even though drivers need to fail cleanly in
ds-&gt;ops-&gt;change_tag_protocol(), DSA will still call dsa_tree_notify()
again, to restore the old tag protocol for potential switches in the
tree where the change did succeeed (before failing for others).

This means for the felix driver that if we report an error in
felix_change_tag_protocol(), we'll get another call where proto_ops ==
old_proto_ops. If we proceed to act upon that, we may do unexpected
things. For example, we will call dsa_tag_8021q_register() twice in a
row, without any dsa_tag_8021q_unregister() in between. Then we will
actually call dsa_tag_8021q_unregister() via old_proto_ops-&gt;teardown,
which (if it manages to run at all, after walking through corrupted data
structures) will leave the ports inoperational anyway.

The bug can be readily reproduced if we force an error while in
tag_8021q mode; this crashes the kernel.

echo ocelot-8021q &gt; /sys/class/net/eno2/dsa/tagging
echo edsa &gt; /sys/class/net/eno2/dsa/tagging # -EPROTONOSUPPORT

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000014
Call trace:
 vcap_entry_get+0x24/0x124
 ocelot_vcap_filter_del+0x198/0x270
 felix_tag_8021q_vlan_del+0xd4/0x21c
 dsa_switch_tag_8021q_vlan_del+0x168/0x2cc
 dsa_switch_event+0x68/0x1170
 dsa_tree_notify+0x14/0x34
 dsa_port_tag_8021q_vlan_del+0x84/0x110
 dsa_tag_8021q_unregister+0x15c/0x1c0
 felix_tag_8021q_teardown+0x16c/0x180
 felix_change_tag_protocol+0x1bc/0x230
 dsa_switch_event+0x14c/0x1170
 dsa_tree_change_tag_proto+0x118/0x1c0

Fixes: 7a29d220f4c0 ("net: dsa: felix: reimplement tagging protocol change with function pointers")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Reviewed-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Link: https://lore.kernel.org/r/20220808125127.3344094-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The way in which dsa_tree_change_tag_proto() works is that when
dsa_tree_notify() fails, it doesn't know whether the operation failed
mid way in a multi-switch tree, or it failed for a single-switch tree.
So even though drivers need to fail cleanly in
ds-&gt;ops-&gt;change_tag_protocol(), DSA will still call dsa_tree_notify()
again, to restore the old tag protocol for potential switches in the
tree where the change did succeeed (before failing for others).

This means for the felix driver that if we report an error in
felix_change_tag_protocol(), we'll get another call where proto_ops ==
old_proto_ops. If we proceed to act upon that, we may do unexpected
things. For example, we will call dsa_tag_8021q_register() twice in a
row, without any dsa_tag_8021q_unregister() in between. Then we will
actually call dsa_tag_8021q_unregister() via old_proto_ops-&gt;teardown,
which (if it manages to run at all, after walking through corrupted data
structures) will leave the ports inoperational anyway.

The bug can be readily reproduced if we force an error while in
tag_8021q mode; this crashes the kernel.

echo ocelot-8021q &gt; /sys/class/net/eno2/dsa/tagging
echo edsa &gt; /sys/class/net/eno2/dsa/tagging # -EPROTONOSUPPORT

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000014
Call trace:
 vcap_entry_get+0x24/0x124
 ocelot_vcap_filter_del+0x198/0x270
 felix_tag_8021q_vlan_del+0xd4/0x21c
 dsa_switch_tag_8021q_vlan_del+0x168/0x2cc
 dsa_switch_event+0x68/0x1170
 dsa_tree_notify+0x14/0x34
 dsa_port_tag_8021q_vlan_del+0x84/0x110
 dsa_tag_8021q_unregister+0x15c/0x1c0
 felix_tag_8021q_teardown+0x16c/0x180
 felix_change_tag_protocol+0x1bc/0x230
 dsa_switch_event+0x14c/0x1170
 dsa_tree_change_tag_proto+0x118/0x1c0

Fixes: 7a29d220f4c0 ("net: dsa: felix: reimplement tagging protocol change with function pointers")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Reviewed-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Link: https://lore.kernel.org/r/20220808125127.3344094-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dsa: felix: fix min gate len calculation for tc when its first gate is closed</title>
<updated>2022-08-09T03:51:56+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2022-08-04T20:28:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7e4babffa6f340a74c820d44d44d16511e666424'/>
<id>7e4babffa6f340a74c820d44d44d16511e666424</id>
<content type='text'>
min_gate_len[tc] is supposed to track the shortest interval of
continuously open gates for a traffic class. For example, in the
following case:

TC 76543210

t0 00000001b 200000 ns
t1 00000010b 200000 ns

min_gate_len[0] and min_gate_len[1] should be 200000, while
min_gate_len[2-7] should be 0.

However what happens is that min_gate_len[0] is 200000, but
min_gate_len[1] ends up being 0 (despite gate_len[1] being 200000 at the
point where the logic detects the gate close event for TC 1).

The problem is that the code considers a "gate close" event whenever it
sees that there is a 0 for that TC (essentially it's level rather than
edge triggered). By doing that, any time a gate is seen as closed
without having been open prior, gate_len, which is 0, will be written
into min_gate_len. Once min_gate_len becomes 0, it's impossible for it
to track anything higher than that (the length of actually open
intervals).

To fix this, we make the writing to min_gate_len[tc] be edge-triggered,
which avoids writes for gates that are closed in consecutive intervals.
However what this does is it makes us need to special-case the
permanently closed gates at the end.

Fixes: 55a515b1f5a9 ("net: dsa: felix: drop oversized frames with tc-taprio instead of hanging the port")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Link: https://lore.kernel.org/r/20220804202817.1677572-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
min_gate_len[tc] is supposed to track the shortest interval of
continuously open gates for a traffic class. For example, in the
following case:

TC 76543210

t0 00000001b 200000 ns
t1 00000010b 200000 ns

min_gate_len[0] and min_gate_len[1] should be 200000, while
min_gate_len[2-7] should be 0.

However what happens is that min_gate_len[0] is 200000, but
min_gate_len[1] ends up being 0 (despite gate_len[1] being 200000 at the
point where the logic detects the gate close event for TC 1).

The problem is that the code considers a "gate close" event whenever it
sees that there is a 0 for that TC (essentially it's level rather than
edge triggered). By doing that, any time a gate is seen as closed
without having been open prior, gate_len, which is 0, will be written
into min_gate_len. Once min_gate_len becomes 0, it's impossible for it
to track anything higher than that (the length of actually open
intervals).

To fix this, we make the writing to min_gate_len[tc] be edge-triggered,
which avoids writes for gates that are closed in consecutive intervals.
However what this does is it makes us need to special-case the
permanently closed gates at the end.

Fixes: 55a515b1f5a9 ("net: dsa: felix: drop oversized frames with tc-taprio instead of hanging the port")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Link: https://lore.kernel.org/r/20220804202817.1677572-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
