linux.git/drivers/net/netconsole.c, branch v7.3-rc2

netconsole: publish the userdata payload with RCU

2026-08-13T13:04:40+00:00

update_userdata() takes target_list_lock to swap nt->userdata and
nt->userdata_length, then frees the old buffer. Since commit
7eab73b18630 ("netconsole: convert to NBCON console infrastructure")
that lock is also the console's device_lock, so writing a userdata value
from configfs serialises against the printk core emitting messages.

The buffer is immutable once published, which is what RCU is for. Move
the string and its length into a single netcons_userdata object and
publish it with rcu_replace_pointer(), freeing the old one with
kfree_rcu().

New userdata design:

0) Unify the userdata fields into a struct netcons_userdata
1) update_userdata() no longer needs target_list_lock.
2) writers stay serialised by dynamic_netconsole_mutex.
3) reading userdata needs an RCU read lock.

No functional change intended.

Signed-off-by: Breno Leitao 
Reviewed-by: Gustavo Luiz Duarte 
Link: https://patch.msgid.link/20260810-netcons-userdata-rcu-v3-1-f65557f769ce@debian.org
Signed-off-by: Paolo Abeni

netconsole: move netpoll_wait_carrier() as netcons_wait_carrier()

2026-07-30T10:14:39+00:00

netpoll_wait_carrier() waits for the egress device carrier during
netconsole setup. Its only caller, netcons_netpoll_setup(), already
lives in netconsole. Move the function into drivers/net/netconsole.c,
drop EXPORT_SYMBOL_GPL() and remove the prototype from .

Rename it to netcons_wait_carrier() for the netcons_ prefix. It now reads
the timeout through netpoll_get_carrier_timeout(), since carrier_timeout
stays in netpoll to keep the netpoll.carrier_timeout parameter.

Signed-off-by: Breno Leitao 
Reviewed-by: Gustavo Luiz Duarte 
Link: https://patch.msgid.link/20260724-netconsole_move_more_final-v1-9-a5f7691db81c@debian.org
Signed-off-by: Paolo Abeni

netconsole: move local_ip/remote_ip/ipv6 to netconsole_target

2026-07-30T10:14:39+00:00

With netpoll_setup() and the packet-building path now living in
netconsole, local_ip, remote_ip and ipv6 in struct netpoll are read
and written only by netconsole. No other netpoll user touches them.

Move the three fields into netconsole_target and switch the packet
builders and setup helpers to take the target instead of the netpoll
handle. struct netpoll is left holding only the device-binding state
that the shared netpoll transport needs.

Signed-off-by: Breno Leitao 
Reviewed-by: Gustavo Luiz Duarte 
Link: https://patch.msgid.link/20260724-netconsole_move_more_final-v1-8-a5f7691db81c@debian.org
Signed-off-by: Paolo Abeni

netconsole: move egress_dev() as netcons_egress_dev()

2026-07-30T10:14:39+00:00

move egress_dev() from netpoll to netconsole, and append netcons_
prefix.

Signed-off-by: Breno Leitao 
Reviewed-by: Gustavo Luiz Duarte 
Link: https://patch.msgid.link/20260724-netconsole_move_more_final-v1-7-a5f7691db81c@debian.org
Signed-off-by: Paolo Abeni

netconsole: move netpoll_take_ipv6() as netcons_take_ipv6()

2026-07-30T10:14:39+00:00

Move netpoll_take_ipv6() to netconsole, and add netcons_ prefix.

Signed-off-by: Breno Leitao 
Reviewed-by: Gustavo Luiz Duarte 
Link: https://patch.msgid.link/20260724-netconsole_move_more_final-v1-6-a5f7691db81c@debian.org
Signed-off-by: Paolo Abeni

netconsole: move netpoll_take_ipv4() as netcons_take_ipv4()

2026-07-30T10:14:39+00:00

Move netpoll_take_ipv4() to netconsole, which is the only user. Rename
it to netcons_take_ipv4() for the netcons_ prefix. The body is
unchanged.

Signed-off-by: Breno Leitao 
Reviewed-by: Gustavo Luiz Duarte 
Link: https://patch.msgid.link/20260724-netconsole_move_more_final-v1-5-a5f7691db81c@debian.org
Signed-off-by: Paolo Abeni

netconsole: move netpoll_local_ip_unset() as netcons_local_ip_unset()

2026-07-30T10:14:39+00:00

Move netpoll_local_ip_unset() from netpoll to netconsole and rename it
to netcons_local_ip_unset();

The body is otherwise unchanged, only the comment's setup-function
reference is updated.

Signed-off-by: Breno Leitao 
Reviewed-by: Gustavo Luiz Duarte 
Link: https://patch.msgid.link/20260724-netconsole_move_more_final-v1-4-a5f7691db81c@debian.org
Signed-off-by: Paolo Abeni

netconsole: take over netpoll_setup() from netpoll

2026-07-30T10:14:39+00:00

netpoll_setup() is only used by netconsole. All the other users use
__netpoll_setup().

Move netpoll_setup() to netconsole, and rename it to
netcons_netpoll_setup().

Pure code motion: the body is unchanged.

Signed-off-by: Breno Leitao 
Reviewed-by: Gustavo Luiz Duarte 
Link: https://patch.msgid.link/20260724-netconsole_move_more_final-v1-3-a5f7691db81c@debian.org
Signed-off-by: Paolo Abeni

Merge branch 'big-tcp-for-udp-tunnels'

2026-07-22T11:49:03+00:00

Alice Mikityanska says:

====================
BIG TCP for UDP tunnels

This series is a follow-up to "BIG TCP without HBH in IPv6", and it adds
support for BIG TCP IPv4/IPv6 workloads in vxlan and geneve. Now that
IPv6 BIG TCP doesn't require stripping the HBH in all various
combinations in tunneled traffic, adding BIG TCP becomes feasible.

Patch 01 adds accessors for the length field in the UDP header, as
suggested by Paolo in review. The usage of udp_set_len is then added in
the following patches that start using length=0 in BIG TCP UDP packets.

Patches 02-04 close the gaps that prevent BIG TCP packets from going
through UDP tunnel code.

Patch 05 validates packets in udp_gro_receive to exclude packets with
length=0 from GRO aggregation.

Patch 06 is for proper formatting in tcpdump (set UDP len to 0 rather
than a trimmed value on overflow).

Patches 07-08 bump up tso_max_size for VXLAN and GENEVE.

Patch 09 adds selftests.
====================$

Link: https://patch.msgid.link/20260710134242.216538-1-alice.kernel@fastmail.im
Signed-off-by: Paolo Abeni

net: Use helpers to get/set UDP len tree-wide

2026-07-22T11:47:02+00:00

Since BIG TCP for UDP tunnels will start using len=0 in the UDP header
as an indicator of a GSO packet bigger than 65535 bytes, this commit
introduces the following getter and setters to use tree-wide, in order
to explicitly mark places where len=0 may be expected, and handle them
properly:

1. udp_set_len() sets uh->len to its real value if it's not bigger than
65535, and to 0 otherwise: to be used in GSO context with aggregated
packets.

2. udp_set_len_short() is to be used when the length is known to fit 16
bits. It WARNs when the caller tries to assign a bigger value if
CONFIG_DEBUG_NET=y.

3. udp_get_len_short() returns len in host byte order: to be used on the
RX side to deal with non-aggregated packets, or to access the raw value
of the len field.

4. udp_get_len() decodes uh->len set by udp_set_len(). It checks whether
the packet is GSO to guard from malformed packets.

At the moment udp_set_len() is not used, a following commit will start
using it after enabling len>65535 for GSO.

Raw uh->len (in network byte order) is still accessed in a few places
for checksum calculation purposes, and to decode len=0 in udpv6_rcv for
jumbograms. udp_rcv and udpv6_rcv will be addressed by the commit that
starts using udp_set_len() to set UDP len=0 for BIG TCP packets in UDP
tunnels.

Signed-off-by: Alice Mikityanska 
Reviewed-by: Willem de Bruijn 
Acked-by: Jason A. Donenfeld 
Link: https://patch.msgid.link/20260710134242.216538-2-alice.kernel@fastmail.im
Reviewed-by: Nikolay Aleksandrov 
Signed-off-by: Paolo Abeni