linux-stable.git/drivers/net/netconsole.c, branch linux-6.16.y

netconsole: Only register console drivers when targets are configured

2025-08-15T14:38:37+00:00

[ Upstream commit bc0cb64db1c765a81f69997d5a28f539e1731bc0 ]

The netconsole driver currently registers the basic console driver
unconditionally during initialization, even when only extended targets
are configured. This results in unnecessary console registration and
performance overhead, as the write_msg() callback is invoked for every
log message only to return early when no matching targets are found.

Optimize the driver by conditionally registering console drivers based
on the actual target configuration. The basic console driver is now
registered only when non-extended targets exist, same as the extended
console. The implementation also handles dynamic target creation through
the configfs interface.

This change eliminates unnecessary console driver registrations,
redundant write_msg() callbacks for unused console types, and associated
lock contention and target list iterations. The optimization is
particularly beneficial for systems using only the most common extended
console type.

Fixes: e2f15f9a79201 ("netconsole: implement extended console support")
Signed-off-by: Breno Leitao 
Link: https://patch.msgid.link/20250609-netcons_ext-v3-1-5336fa670326@debian.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

netconsole: fix appending sysdata when sysdata_fields == SYSDATA_RELEASE

2025-06-10T22:52:08+00:00

Before appending sysdata, prepare_extradata() checks if any feature is
enabled in sysdata_fields (and exits early if none is enabled).

When SYSDATA_RELEASE was introduced, we missed adding it to the list of
features being checked against sysdata_fields in prepare_extradata().
The result was that, if only SYSDATA_RELEASE is enabled in
sysdata_fields, we incorreclty exit early and fail to append the
release.

Instead of checking specific bits in sysdata_fields, check if
sysdata_fields has ALL bit zeroed and exit early if true. This fixes
case when only SYSDATA_RELEASE enabled and makes the code more general /
less error prone in future feature implementation.

Signed-off-by: Gustavo Luiz Duarte 
Reviewed-by: Breno Leitao 
Fixes: cfcc9239e78a ("netconsole: append release to sysdata")
Link: https://patch.msgid.link/20250609-netconsole-fix-v1-1-17543611ae31@gmail.com
Signed-off-by: Jakub Kicinski

netconsole: append release to sysdata

2025-03-21T17:59:25+00:00

Append the init_utsname()->release to sysdata buffer before sending the
message in case the feature is set.

Signed-off-by: Breno Leitao 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250314-netcons_release-v1-4-07979c4b86af@debian.org
Signed-off-by: Paolo Abeni

netconsole: add 'sysdata' suffix to related functions

2025-03-21T17:59:24+00:00

This commit appends a common "sysdata" suffix to functions responsible
for appending data to sysdata.

This change enhances code clarity and prevents naming conflicts with
other "append" functions, particularly in anticipation of the upcoming
inclusion of the `release` field in the next patch.

Signed-off-by: Breno Leitao 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250314-netcons_release-v1-3-07979c4b86af@debian.org
Signed-off-by: Paolo Abeni

netconsole: implement configfs for release_enabled

2025-03-21T17:59:24+00:00

Implement the configfs helpers to show and set release_enabled configfs
directories under userdata.

When enabled, set the feature bit in netconsole_target->sysdata_fields.

Signed-off-by: Breno Leitao 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250314-netcons_release-v1-2-07979c4b86af@debian.org
Signed-off-by: Paolo Abeni

netconsole: introduce 'release' as a new sysdata field

2025-03-21T17:59:24+00:00

This commit adds a new feature to the sysdata structure, allowing the
kernel release/version to be appended as part of sysdata. Additionally,
it updates the logic to count this new field as a used entry when
enabled.

Signed-off-by: Breno Leitao 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250314-netcons_release-v1-1-07979c4b86af@debian.org
Signed-off-by: Paolo Abeni

net, treewide: define and use MAC_ADDR_STR_LEN

2025-03-19T18:17:58+00:00

There are a few places in the tree which compute the length of the
string representation of a MAC address as 3 * ETH_ALEN - 1. Define a
constant for this and use it where relevant. No functionality changes
are expected.

Signed-off-by: Uday Shankar 
Reviewed-by: Michal Swiatkowski 
Acked-by: Johannes Berg 
Reviewed-by: Breno Leitao 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250312-netconsole-v6-1-3437933e79b8@purestorage.com
Signed-off-by: Paolo Abeni

netconsole: add task name to extra data fields

2025-03-04T14:28:28+00:00

This is the core patch for this whole patchset. Add support for
including the current task's name in netconsole's extra data output.
This adds a new append_taskname() function that writes the task name
(from current->comm) into the target's extradata buffer, similar to how
CPU numbers are handled.

The task name is included when the SYSDATA_TASKNAME field is set,
appearing in the format "taskname=" in the output. This additional
context can help with debugging by showing which task generated each
console message.

Signed-off-by: Breno Leitao 
Reviewed-by: Simon Horman 
Signed-off-by: Paolo Abeni

netconsole: add configfs controls for taskname sysdata feature

2025-03-04T14:28:28+00:00

Add configfs interface to enable/disable the taskname sysdata feature.
This adds the following functionality:

The implementation follows the same pattern as the existing CPU number
feature, ensuring consistent behavior and error handling across sysdata
features.

Signed-off-by: Breno Leitao 
Reviewed-by: Simon Horman 
Signed-off-by: Paolo Abeni

netconsole: add taskname to extradata entry count

2025-03-04T14:28:28+00:00

New SYSDATA_TASKNAME feature flag to track when taskname append is enabled.

Additional check in count_extradata_entries() to include taskname in
total, counting it as an entry in extradata. This function is used to
check if we are not overflowing the number of extradata items.

Signed-off-by: Breno Leitao 
Reviewed-by: Simon Horman 
Signed-off-by: Paolo Abeni