Add documentation explaining the msgid feature in netconsole.
This feature appends unique id to the userdata dictionary. The message
ID is populated from a per-target 32 bit counter which is incremented
for each message sent to the target. This allows a target to detect if
messages are dropped before reaching the target.
Signed-off-by: Gustavo Luiz Duarte <gustavold@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add documentation explaining the kernel release auto-population feature
in netconsole.
This feature appends kernel version information to the userdata
dictionary in every message sent when enabled via the `release_enabled`
file in the configfs hierarchy.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250314-netcons_release-v1-6-07979c4b86af@debian.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Currently, netconsole has two methods of configuration - module
parameter and configfs. The former interface allows for netconsole
activation earlier during boot (by specifying the module parameter on
the kernel command line), so it is preferred for debugging issues which
arise before userspace is up/the configfs interface can be used. The
module parameter syntax requires specifying the egress interface name.
This requirement makes it hard to use for a couple reasons:
- The egress interface name can be hard or impossible to predict. For
example, installing a new network card in a system can change the
interface names assigned by the kernel.
- When constructing the module parameter, one may have trouble
determining the original (kernel-assigned) name of the interface
(which is the name that should be given to netconsole) if some stable
interface naming scheme is in effect. A human can usually look at
kernel logs to determine the original name, but this is very painful
if automation is constructing the parameter.
For these reasons, allow selection of the egress interface via MAC
address when configuring netconsole using the module parameter. Update
the netconsole documentation with an example of the new syntax.
Selection of egress interface by MAC address via configfs is far less
interesting (since when this interface can be used, one should be able
to easily convert between MAC address and interface name), so it is left
unimplemented.
Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Reviewed-by: Breno Leitao <leitao@debian.org>
Tested-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250312-netconsole-v6-2-3437933e79b8@purestorage.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Add documentation for the netconsole task name feature in
Documentation/networking/netconsole.rst. This explains how to enable
task name via configfs and demonstrates the output format.
The documentation includes:
- How to enable/disable the feature via taskname_enabled
- The format of the task name in the output
- An example showing the task name appearing in messages
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Update the netconsole documentation to explain the new feature that
allows automatic population of the CPU number.
The key changes include introducing a new section titled "CPU number
auto population in userdata", explaining how to enable the CPU number
auto-population feature by writing to the "populate_cpu_nr" file in the
netconsole configfs hierarchy.
This documentation update ensures users are aware of the new CPU number
auto-population functionality and how to leverage it for better
demultiplexing and visibility of parallel netconsole output.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Enhance observability of netconsole. Packet sends can fail.
Start tracking at least two failure possibilities: ENOMEM and
NET_XMIT_DROP for every target. Stats are exposed via an additional
attribute in CONFIGFS.
The exposed statistics allows easier debugging of cases when netconsole
messages were not seen by receivers, eliminating the guesswork if the
sender thinks that messages in question were sent out.
Stats are not reset on enable/disable/change remote ip/etc, they
belong to the netcons target itself.
Reported-by: Breno Leitao <leitao@debian.org>
Closes: https://lore.kernel.org/all/ZsWoUzyK5du9Ffl+@gmail.com/
Signed-off-by: Maksym Kutsevol <max@kutsevol.com>
Link: https://patch.msgid.link/20241202-netcons-add-udp-send-fail-statistics-to-netconsole-v5-2-70e82239f922@kutsevol.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add a space (' ') prefix to every userdata line to match docs for
dev-kmsg. To account for this extra character in each userdata entry,
reduce userdata entry names (directory name) from 54 characters to 53.
According to the dev-kmsg docs, a space is used for subsequent lines to
mark them as continuation lines.
> A line starting with ' ', is a continuation line, adding
> key/value pairs to the log message, which provide the machine
> readable context of the message, for reliable processing in
> userspace.
Testing for this patch::
cd /sys/kernel/config/netconsole && mkdir cmdline0
cd cmdline0
mkdir userdata/test && echo "hello" > userdata/test/value
mkdir userdata/test2 && echo "hello2" > userdata/test2/value
echo "message" > /dev/kmsg
Outputs::
6.8.0-rc5-virtme,12,493,231373579,-;message
test=hello
test2=hello2
And I confirmed all testing works as expected from the original patchset
Fixes: df03f830d0 ("net: netconsole: cache userdata formatted string in netconsole_target")
Signed-off-by: Matthew Wood <thepacketgeek@gmail.com>
Reviewed-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20240308002525.248672-1-thepacketgeek@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add a new User Data section to the netconsole docs to describe the
appending of user data capability (for netconsole dynamic configuration)
with usage and netconsole output examples.
Co-developed-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Matthew Wood <thepacketgeek@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With the previous patches, there is no more limitation at modifying the
targets created at boot time (or module load time).
Document the way on how to create the configfs directories to be able to
modify these netconsole targets.
The design discussion about this topic could be found at:
https://lore.kernel.org/all/ZRWRal5bW93px4km@gmail.com/
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20231012111401.333798-5-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Create a new netconsole runtime option that prepends the kernel version in
the netconsole message. This is useful to map kernel messages to kernel
version in a simple way, i.e., without checking somewhere which kernel
version the host that sent the message is using.
If this option is selected, then the "<release>," is prepended before the
netconsole message. This is an example of a netconsole output, with
release feature enabled:
6.4.0-01762-ga1ba2ffe946e;12,426,112883998,-;this is a test
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20230714111330.3069605-1-leitao@debian.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Correct spelling problems for Documentation/networking/ as reported
by codespell.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: Jiri Pirko <jiri@nvidia.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/20230129231053.20863-5-rdunlap@infradead.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
- add SPDX header;
- add a document title;
- mark code blocks and literals as such;
- mark tables as such;
- add notes markups;
- adjust identation, whitespaces and blank lines;
- add to networking/index.rst.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
