This patch series introduces a new configfs attribute that enables sending
messages directly through netconsole without going through the kernel's logging
infrastructure.
This feature allows users to send custom messages, alerts, or status updates
directly to netconsole receivers by writing to
/sys/kernel/config/netconsole/<target>/send_msg, without poluting kernel
buffers, and sending msgs to the serial, which could be slow.
At Meta this is currently used in two cases right now (through printk by
now):
a) When a new workload enters or leave the machine.
b) From time to time, as a "ping" to make sure the netconsole/machine
is alive.
The implementation reuses the existing message transmission functions
(send_msg_udp() and send_ext_msg_udp()) to handle both basic and extended
message formats.
Regarding code organization, this version uses forward declarations for
send_msg_udp() and send_ext_msg_udp() functions rather than relocating them
within the file. While forward declarations do add a small amount of
redundancy, they avoid the larger churn that would result from moving entire
function definitions.
---
Breno Leitao (4):
netconsole: extract message fragmentation into send_msg_udp()
netconsole: Add configfs attribute for direct message sending
selftests/netconsole: Switch to configfs send_msg interface
Documentation: netconsole: Document send_msg configfs attribute
Documentation/networking/netconsole.rst | 40 +++++++++++++++
drivers/net/netconsole.c | 59 ++++++++++++++++++----
.../selftests/drivers/net/netcons_sysdata.sh | 2 +-
3 files changed, 91 insertions(+), 10 deletions(-)
---
base-commit: ab084f0b8d6d2ee4b1c6a28f39a2a7430bdfa7f0
change-id: 20251127-netconsole_send_msg-89813956dc23
Best regards,
--
Breno Leitao <leitao@debian.org>