Commit Graph

948 Commits

Author SHA1 Message Date
Eric Dumazet
b8a39a09ae net: remove WARN_ON_ONCE() from sk_mc_loop()
sk_mc_loop() can be called for sockets that are neither AF_INET
nor AF_INET6 (e.g. AF_PACKET sockets when sending packets via raw/packet
socket over virtual devices such as VRF or ipvlan).

In such cases, sk_family is not AF_INET/AF_INET6 and sk_mc_loop() falls
through the switch statement and triggers WARN_ON_ONCE(1).

Non-INET sockets do not support IP_MULTICAST_LOOP or IPV6_MULTICAST_LOOP
options, so loopback should default to true without generating a warning.

Fixes: f60e5990d9 ("ipv6: protect skb->sk accesses from recursive dereference inside the stack")
Reported-by: syzbot+22c3218a6fa219e47321@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6a72024c.13623e66.bdc14.0019.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260804152048.2134341-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-08-06 13:10:16 +02:00
Linus Torvalds
d326f83e81 Lots of fixes, double the count even for the "new normal".
Largely due to my time off followed by a networking conference
 which distracted most maintainers (less so the AI generators).
 
 Including fixes from Bluetooth and WiFi.
 
 Current release - regressions:
 
  - wifi: mt76: fix MAC address for non OF pcie cards
 
 Current release - new code bugs:
 
  - mptcp: fix BUILD_BUG_ON on legacy ARM config
 
  - wifi: cfg80211: guard optional PMSR nominal time
 
 Previous releases - regressions:
 
  - qrtr: ns: raise node count limit to 512, we arbitrarily picked
    256 as a limit, turns out it was too low for real world deployments
 
  - vhost-net: fix TX stall when vhost owns virtio-net header
 
  - eth: amd-xgbe: fix MAC_AUTO_SW handling in CL37 AN
 
  - wifi: ath12k: fix low MLO RX throughput on WCN7850
 
 Previous releases - always broken:
 
  - number of random AI fixes for SCTP, RDS and TIPC protocols
 
  - more AI-looking fixes for WiFi drivers
 
  - number of fixes for missing pointer reloading after skb pull
 
  - reject BPF redirect use from qdisc qevent block
 
  - tcp: initialize standalone TCP-AO response padding
 
  - vsock/virtio: collapse receive queue under memory pressure to avoid
    client OOMing the host with tiny messages
 
  - ipv4: icmp: fill flow parameters in icmp_route_lookup decoy lookup,
    make sure the ICMP response routing follows the routing policy
 
  - gro: fix double aggregation of flush-marked skbs
 
  - ovpn: fix various refcount bugs
 
  - tls: device: push pending open record on splice EOF
 
  - eth: mlx5:
   - use sender devcom for MPV master-up
   - fix MCIA register buffer overflow on 32 dword reads
 
 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-7.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from Jakub Kicinski:
 "Lots of fixes, double the count even for the 'new normal'. Largely due
  to my time off followed by a networking conference which distracted
  most maintainers (less so the AI generators).

  Including fixes from Bluetooth and WiFi.

  Current release - regressions:

   - wifi: mt76: fix MAC address for non OF pcie cards

  Current release - new code bugs:

   - mptcp: fix BUILD_BUG_ON on legacy ARM config

   - wifi: cfg80211: guard optional PMSR nominal time

  Previous releases - regressions:

   - qrtr: ns: raise node count limit to 512, we arbitrarily picked
     256 as a limit, turns out it was too low for real world deployments

   - vhost-net: fix TX stall when vhost owns virtio-net header

   - eth: amd-xgbe: fix MAC_AUTO_SW handling in CL37 AN

   - wifi: ath12k: fix low MLO RX throughput on WCN7850

  Previous releases - always broken:

   - number of random AI fixes for SCTP, RDS and TIPC protocols

   - more AI-looking fixes for WiFi drivers

   - number of fixes for missing pointer reloading after skb pull

   - reject BPF redirect use from qdisc qevent block

   - tcp: initialize standalone TCP-AO response padding

   - vsock/virtio: collapse receive queue under memory pressure to avoid
     client OOMing the host with tiny messages

   - ipv4: icmp: fill flow parameters in icmp_route_lookup decoy lookup,
     make sure the ICMP response routing follows the routing policy

   - gro: fix double aggregation of flush-marked skbs

   - ovpn: fix various refcount bugs

   - tls: device: push pending open record on splice EOF

   - eth: mlx5:
      - use sender devcom for MPV master-up
      - fix MCIA register buffer overflow on 32 dword reads"

* tag 'net-7.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (234 commits)
  drop_monitor: perform u64_stats updates under IRQ-disabled section
  drop_monitor: fix size calculations for 64-bit attributes
  net: drop_monitor: fix info leak in NET_DM_ATTR_PAYLOAD
  mptcp: fix BUILD_BUG_ON on legacy ARM config
  selftests: mptcp: userspace_pm: fix undefined variable port
  mptcp: fix stale skb->sk reference on subflow close
  mptcp: pm: userspace: fix use-after-free in get_local_id
  mptcp: decrement subflows counter on failed passive join
  mac802154: hold an interface reference across the scan worker
  sctp: don't free the ASCONF's own transport in DEL-IP processing
  phonet: check register_netdevice_notifier() error in phonet_device_init()
  phonet: pep: fix use-after-free in pep_get_sb()
  bnge/bng_re: fix ring ID widths
  tipc: fix integer overflow in tipc_recvmsg() and tipc_recvstream()
  net: airoha: fix ETS channel derivation in airoha_tc_setup_qdisc_ets()
  mctp: check register_netdevice_notifier() error in mctp_device_init()
  ptp: netc: explicitly clear TMR_OFF during initialization
  rds: tcp: unregister sysctl before tearing down listen socket
  ipv6: Change allocation flags to match rcu_read_lock section requirements
  net: slip: serialize receive against buffer reallocation
  ...
2026-07-23 12:58:08 -07:00
Kuniyuki Iwashima
d505577792 net: Call net_enable_timestamp() before failure in sk_clone().
When sk_clone() fails, sk_destruct() is called for the new socket.

If the parent socket has SK_FLAGS_TIMESTAMP in sk->sk_flags,
net_disable_timestamp() is called for the child socket even though
net_enable_timestamp() is not called for it.

Let's call net_enable_timestamp() before any failure path in
sk_clone().

Fixes: 704da560c0 ("tcp: update the netstamp_needed counter when cloning sockets")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/all/20260709032007.9E4D61F000E9@smtp.kernel.org/
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260709183315.965751-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-07-21 09:14:59 -07:00
Kuniyuki Iwashima
98da8ce87d soreuseport: Clear sk_reuseport_cb before failure in sk_clone().
When sk_clone() fails, sk_destruct() is called for the new socket.

If the parent socket has sk->sk_reuseport_cb, the child will call
reuseport_detach_sock() for the reuseport group.

Let's clear sk->sk_reuseport_cb before any failure path in sk_clone().

Note that this was not a problem before the cited commit because
reuseport_detach_sock() did nothing if the socket was not found in
the reuseport array.

Fixes: 5dc4c4b7d4 ("bpf: Introduce BPF_MAP_TYPE_REUSEPORT_SOCKARRAY")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/all/20260709032007.9E4D61F000E9@smtp.kernel.org/
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260709183315.965751-2-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-07-21 09:14:59 -07:00
Matt Bobrowski
7cbd0c4ceb bpf: Fix UAF in sock clone early bailouts
Similar to recent commit 9b51a6155d ("bpf,fork: wipe ->bpf_storage
before bailouts that access it"), sk_clone() performs an initial
shallow copy of the socket field ->sk_bpf_storage via sock_copy()
for the cloned socket newsk.

If sk_clone() bails out early (e.g. if sk_filter_charge() fails) prior
to calling bpf_sk_storage_clone(), newsk->sk_bpf_storage still points
to the parent socket's BPF local storage. When newsk is subsequently
freed via sk_free(), the deallocation path (__sk_destruct() ->
bpf_sk_storage_free()) destroys the parent socket's BPF local storage,
leading to a use-after-free (UAF) on the parent socket.

Fix this by resetting newsk->sk_bpf_storage to NULL immediately after
sock_copy() in sk_clone(), and remove the now redundant initialization
from bpf_sk_storage_clone().

Fixes: 6ac99e8f23 ("bpf: Introduce bpf sk local storage")
Fixes: f12dd75959 ("bpf: net: Set sk_bpf_storage back to NULL for cloned sk")
Signed-off-by: Matt Bobrowski <mattbobrowski@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260709025316.999913-1-mattbobrowski@google.com
2026-07-09 18:44:16 +02:00
Jakub Kicinski
dad4d4b92a Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR (net-7.1-rc8).

Conflicts:

drivers/net/ethernet/wangxun/txgbe/txgbe_aml.c
  f67aead16e ("net: txgbe: rework service event handling")
  57d39faed4 ("net: txgbe: improve functions of AML 40G devices")

net/rds/info.c
  512db8267b ("rds: mark snapshot pages dirty in rds_info_getsockopt()")
  6e94eeb2a2 ("rds: convert to getsockopt_iter")

Adjacent changes:

include/net/sock.h
  1ee90b77b7 ("net: guard timestamp cmsgs to real error queue skbs")
  f0de88303d ("net: make is_skb_wmem() available to modules")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-06-11 14:33:35 -07:00
Willem de Bruijn
73f1a618b0 net: ensure SCM_TXTIME delivery time is no older than system boot
Limit input to sane values to avoid having to add tests later in the
kernel hot path, e.g., in FQ.

SCM_TXTIME timestamps are converted to signed ktime_t when assigned to
skb->tstamp. Avoid having negative values overflow into large positive
ones when again used as u64, e.g., in FQ time_to_send.

For CLOCK_MONOTONIC, only allow positive values.

For CLOCK_REALTIME and CLOCK_TAI, allow equivalent values, i.e., no
older than the boot of the machine.

skb->tstamp zero is a special case signaling feature off. This is not
converted between clockids.

Handle the special case where the realtime clock is set so small that
real - mono is negative, however unlikely in practice.

Ideally we would also set a sane upper bound, but that would require
reading the clock, which is an expensive operation. Continue to defer
that validation to users of the data. FQ already does this.

Bound rather than return error on older timestamps. This is the
existing policy e.g., in FQ.

Signed-off-by: Willem de Bruijn <willemb@google.com>

----

Changes
  v1 -> v2
    - remove spurious semicolon at end of switch
    - remove Fixes tag

Link: https://patch.msgid.link/20260604194221.3319080-2-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-06-08 16:00:05 -07:00
Eric Dumazet
5d39580f68 tcp: restrict SO_ATTACH_FILTER to priv users
This patch restricts the use of SO_ATTACH_FILTER (cBPF) on TCP sockets
to users with CAP_NET_ADMIN capability.

This blocks potential side-channel attack where an unprivileged application
attaches a filter to leak TCP sequence/acknowledgment numbers.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Tamir Shahar <tamirthesis@gmail.com>
Reported-by: Amit Klein <aksecurity@gmail.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Cc: Song Liu <song@kernel.org>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Stanislav Fomichev <sdf@fomichev.me>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-06-08 15:37:10 -07:00
Jakub Kicinski
8d72997dab Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR (net-7.1-rc7).

Silent conflicts:

net/wireless/nl80211.c
  cb9959ab5f ("wifi: cfg80211: enforce HE/EHT cap/oper consistency")
  a384ae9699 ("wifi: cfg80211: move AP HT/VHT/... operation to beacon info")
https://lore.kernel.org/aiGJDaHV4UlCexIQ@sirena.org.uk

Conflicts:

drivers/net/wireless/intel/iwlwifi/mld/ap.c
  a342c99cb7 ("wifi: iwlwifi: mld: honor BSS_CHANGED_BEACON_ENABLED")
  9bf1b409af ("wifi: iwlwifi: mld: send tx power constraints before link activation")
https://lore.kernel.org/ah2bfedhV45ZxMO8@sirena.org.uk

drivers/net/wireless/intel/iwlwifi/pcie/drv.c
  093305d801 ("wifi: iwlwifi: pcie: simplify the resume flow if fast resume is not used")
  e2323929a6 ("wifi: iwlwifi: pcie: add debug print for resume flow if powered off")
https://lore.kernel.org/ah2bfedhV45ZxMO8@sirena.org.uk

Adjacent changes:

drivers/net/ethernet/airoha/airoha_eth.c
  b38cae85d1 ("net: airoha: Fix use-after-free in metadata dst teardown")
  ec6c391bcc ("net: airoha: Introduce airoha_gdm_dev struct")

drivers/net/ethernet/microchip/lan743x_main.c
  8173d22b21 ("net: lan743x: permit VLAN-tagged packets up to configured MTU")
  e3c6508a46 ("net: lan743x: avoid netdev-based logging before netdev registration")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-06-04 15:29:04 -07:00
Kuniyuki Iwashima
b748765019 net: Annotate sk->sk_write_space() for UDP SOCKMAP.
UDP TX skb->destructor() is sock_wfree(), and UDP holds lock_sock()
only for UDP_CORK / MSG_MORE sendmsg().

Otherwise, sk->sk_write_space() may be read locklessly while SOCKMAP
rewrites sk->sk_write_space().

Let's use WRITE_ONCE() and READ_ONCE() for sk->sk_write_space().

Note that the write side is annotated by commit 2ef2b20cf4
("net: annotate data-races around sk->sk_{data_ready,write_space}").

Fixes: 7b98cd42b0 ("bpf: sockmap: Add UDP support")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://patch.msgid.link/20260529193941.3897256-1-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-06-02 11:44:43 -07:00
Eric Dumazet
f0de88303d net: make is_skb_wmem() available to modules
Following patch will use is_skb_wmem() from fq_codel.

Provide __sock_wfree() only if CONFIG_INET=y

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@toke.dk>
Link: https://patch.msgid.link/20260512094859.3673997-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-05-13 19:13:41 -07:00
Jakub Kicinski
b025461303 tcp: update window_clamp when SO_RCVBUF is set
Commit under Fixes moved recomputing the window clamp to
tcp_measure_rcv_mss() (when scaling_ratio changes).
I suspect it missed the fact that we don't recompute the clamp
when rcvbuf is set. Until scaling_ratio changes we are
stuck with the old window clamp which may be based on
the small initial buffer. scaling_ratio may never change.

Inspired by Eric's recent commit d1361840f8 ("tcp: fix
SO_RCVLOWAT and RCVBUF autotuning") plumb the user action
thru to TCP and have it update the clamp.

A smaller fix would be to just have tcp_rcvbuf_grow()
adjust the clamp even if SOCK_RCVBUF_LOCK is set.
But IIUC this is what we were trying to get away from
in the first place.

Fixes: a2cbb16039 ("tcp: Update window clamping condition")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Eric Dumazet <edumaze@google.com>
Link: https://patch.msgid.link/20260408001438.129165-1-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-04-13 15:32:35 +02:00
Eric Dumazet
fb37aea2a0 net: change sk_filter_trim_cap() to return a drop_reason by value
Current return value can be replaced with the drop_reason,
reducing kernel bloat:

$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 0/2 grow/shrink: 1/11 up/down: 32/-603 (-571)
Function                                     old     new   delta
tcp_v6_rcv                                  3135    3167     +32
unix_dgram_sendmsg                          1731    1726      -5
netlink_unicast                              957     945     -12
netlink_dump                                1372    1359     -13
sk_filter_trim_cap                           882     858     -24
tcp_v4_rcv                                  3143    3111     -32
__pfx_tcp_filter                              32       -     -32
netlink_broadcast_filtered                  1633    1595     -38
sock_queue_rcv_skb_reason                    126      76     -50
tun_net_xmit                                1127    1074     -53
__sk_receive_skb                             690     632     -58
udpv6_queue_rcv_one_skb                      935     869     -66
udp_queue_rcv_one_skb                        919     853     -66
tcp_filter                                   154       -    -154
Total: Before=29722783, After=29722212, chg -0.00%

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260409145625.2306224-6-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-12 14:30:25 -07:00
Eric Dumazet
c78bcbd519 net: change sk_filter_reason() to return the reason by value
sk_filter_trim_cap will soon return the reason by value,
do the same for sk_filter_reason().

$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-21 (-21)
Function                                     old     new   delta
sock_queue_rcv_skb_reason                    128     126      -2
tun_net_xmit                                1146    1127     -19
Total: Before=29722661, After=29722640, chg -0.00%

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260409145625.2306224-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-12 14:30:25 -07:00
Eric Dumazet
900f27fb79 net: change sock_queue_rcv_skb_reason() to return a drop_reason
Change sock_queue_rcv_skb_reason() to return the drop_reason directly
instead of using a reference.

This is part of an effort to remove stack canaries and reduce bloat.

$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 0/0 grow/shrink: 3/7 up/down: 79/-301 (-222)
Function                                     old     new   delta
vsock_queue_rcv_skb                           50      79     +29
ipmr_cache_report                           1290    1315     +25
ip6mr_cache_report                          1322    1347     +25
packet_rcv_spkt                              329     327      -2
sock_queue_rcv_skb_reason                    166     128     -38
raw_rcv_skb                                  122      80     -42
ping_queue_rcv_skb                           109      61     -48
ping_rcv                                     215     162     -53
rawv6_rcv_skb                                278     224     -54
raw_rcv                                      591     527     -64
Total: Before=29722890, After=29722668, chg -0.00%

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260409145625.2306224-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-12 14:30:25 -07:00
Jiayuan Chen
1a6b396538 net: initialize sk_rx_queue_mapping in sk_clone()
sk_clone() initializes sk_tx_queue_mapping via sk_tx_queue_clear()
but does not initialize sk_rx_queue_mapping. Since this field is in
the sk_dontcopy region, it is neither copied from the parent socket
by sock_copy() nor zeroed by sk_prot_alloc() (called without
__GFP_ZERO from sk_clone).

Commit 03cfda4fa6 ("tcp: fix another uninit-value
(sk_rx_queue_mapping)") attempted to fix this by introducing
sk_mark_napi_id_set() with force_set=true in tcp_child_process().
However, sk_mark_napi_id_set() -> sk_rx_queue_set() only writes
when skb_rx_queue_recorded(skb) is true. If the 3-way handshake
ACK arrives through a device that does not record rx_queue (e.g.
loopback or veth), sk_rx_queue_mapping remains uninitialized.

When a subsequent data packet arrives with a recorded rx_queue,
sk_mark_napi_id() -> sk_rx_queue_update() reads the uninitialized
field for comparison (force_set=false path), triggering KMSAN.

This was reproduced by establishing a TCP connection over loopback
(which does not call skb_record_rx_queue), then attaching a BPF TC
program on lo ingress to set skb->queue_mapping on data packets:

BUG: KMSAN: uninit-value in tcp_v4_do_rcv (net/ipv4/tcp_ipv4.c:1875)
 tcp_v4_do_rcv (net/ipv4/tcp_ipv4.c:1875)
 tcp_v4_rcv (net/ipv4/tcp_ipv4.c:2287)
 ip_protocol_deliver_rcu (net/ipv4/ip_input.c:207)
 ip_local_deliver_finish (net/ipv4/ip_input.c:242)
 ip_local_deliver (net/ipv4/ip_input.c:262)
 ip_rcv (net/ipv4/ip_input.c:573)
 __netif_receive_skb (net/core/dev.c:6294)
 process_backlog (net/core/dev.c:6646)
 __napi_poll (net/core/dev.c:7710)
 net_rx_action (net/core/dev.c:7929)
 handle_softirqs (kernel/softirq.c:623)
 do_softirq (kernel/softirq.c:523)
 __local_bh_enable_ip (kernel/softirq.c:?)
 __dev_queue_xmit (net/core/dev.c:?)
 ip_finish_output2 (net/ipv4/ip_output.c:237)
 ip_output (net/ipv4/ip_output.c:438)
 __ip_queue_xmit (net/ipv4/ip_output.c:534)
 __tcp_transmit_skb (net/ipv4/tcp_output.c:1693)
 tcp_write_xmit (net/ipv4/tcp_output.c:3064)
 tcp_sendmsg_locked (net/ipv4/tcp.c:?)
 tcp_sendmsg (net/ipv4/tcp.c:1465)
 inet_sendmsg (net/ipv4/af_inet.c:865)
 sock_write_iter (net/socket.c:1195)
 vfs_write (fs/read_write.c:688)
 ...
Uninit was created at:
 kmem_cache_alloc_noprof (mm/slub.c:4873)
 sk_prot_alloc (net/core/sock.c:2239)
 sk_alloc (net/core/sock.c:2301)
 inet_create (net/ipv4/af_inet.c:334)
 __sock_create (net/socket.c:1605)
 __sys_socket (net/socket.c:1747)

Fix this at the root by adding sk_rx_queue_clear() alongside
sk_tx_queue_clear() in sk_clone().

Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260407084219.95718-1-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-08 19:28:05 -07:00
Eric Dumazet
6f459eda8b tcp: add tcp_release_cb_cond() helper
Majority of tcp_release_cb() calls do nothing at all.

Provide tcp_release_cb_cond() helper so that release_sock()
can avoid these calls.

Also hint the compiler that __release_sock() and wake_up()
are rarely called.

$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-77 (-77)
Function                                     old     new   delta
release_sock                                 258     181     -77
Total: Before=25235790, After=25235713, chg -0.00%

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260310124451.2280968-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-03-12 13:22:03 +01:00
Eric Dumazet
8341c989ac net: remove addr_len argument of recvmsg() handlers
Use msg->msg_namelen as a place holder instead of a
temporary variable, notably in inet[6]_recvmsg().

This removes stack canaries and allows tail-calls.

$ scripts/bloat-o-meter -t vmlinux.old vmlinux
add/remove: 0/0 grow/shrink: 2/19 up/down: 26/-532 (-506)
Function                                     old     new   delta
rawv6_recvmsg                                744     767     +23
vsock_dgram_recvmsg                           55      58      +3
vsock_connectible_recvmsg                     50      47      -3
unix_stream_recvmsg                          161     158      -3
unix_seqpacket_recvmsg                        62      59      -3
unix_dgram_recvmsg                            42      39      -3
tcp_recvmsg                                  546     543      -3
mptcp_recvmsg                               1568    1565      -3
ping_recvmsg                                 806     800      -6
tcp_bpf_recvmsg_parser                       983     974      -9
ip_recv_error                                588     576     -12
ipv6_recv_rxpmtu                             442     428     -14
udp_recvmsg                                 1243    1224     -19
ipv6_recv_error                             1046    1024     -22
udpv6_recvmsg                               1487    1461     -26
raw_recvmsg                                  465     437     -28
udp_bpf_recvmsg                             1027     984     -43
sock_common_recvmsg                          103      27     -76
inet_recvmsg                                 257     175     -82
inet6_recvmsg                                257     175     -82
tcp_bpf_recvmsg                              663     568     -95
Total: Before=25143834, After=25143328, chg -0.00%

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260227151120.1346573-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-02 18:17:17 -08:00
Jiayuan Chen
58e443b773 net: fix sock compilation error under CONFIG_PREEMPT_RT
When CONFIG_PREEMPT_RT is enabled, __SPIN_LOCK_UNLOCKED() expands to a
brace-enclosed initializer rather than a compound literal, which cannot
be used in assignment expressions. This causes a build failure:

  net/core/sock.c:3787:29: error: expected expression before '{' token
   3787 |                 tmp.slock = __SPIN_LOCK_UNLOCKED(tmp.slock);

Use declaration-with-initializer instead of assignment, consistent with
how __SPIN_LOCK_UNLOCKED() is used elsewhere in the kernel (e.g.
DEFINE_SPINLOCK).

Fixes: 5151ec54f5 ("net: use try_cmpxchg() in lock_sock_nested()")
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260228111319.79506-1-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-28 07:42:39 -08:00
Eric Dumazet
5151ec54f5 net: use try_cmpxchg() in lock_sock_nested()
Add a fast path in lock_sock_nested(), to avoid acquiring
the socket spinlock only to set @owned to one:

        spin_lock_bh(&sk->sk_lock.slock);
        if (unlikely(sock_owned_by_user_nocheck(sk)))
                __lock_sock(sk);
        sk->sk_lock.owned = 1;
        spin_unlock_bh(&sk->sk_lock.slock);

On x86_64 compiler generates something quite efficient:

00000000000077c0 <lock_sock_nested>:
    77c0:       f3 0f 1e fa                 endbr64
    77c4:       e8 00 00 00 00              call   __fentry__
    77c9:       b9 01 00 00 00              mov    $0x1,%ecx
    77ce:       31 c0                       xor    %eax,%eax
    77d0:       f0 48 0f b1 8f 48 01 00 00  lock cmpxchg %rcx,0x148(%rdi)
    77d9:       75 06                       jne    slow_path
    77db:       2e e9 00 00 00 00           cs jmp __x86_return_thunk-0x4
slow_path:      ...

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://patch.msgid.link/20260226021215.1764237-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-27 17:25:45 -08:00
Jakub Kicinski
0314e382cf Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR (net-7.0-rc2).

Conflicts:

tools/testing/selftests/drivers/net/hw/rss_ctx.py
  19c3a2a81d ("selftests: drv-net: rss: Generate unique ports for RSS context tests")
  ce5a0f4612 ("selftests: drv-net: rss_ctx: test RSS contexts persist after ifdown/up")

include/net/inet_connection_sock.h
  858d2a4f67 ("tcp: fix potential race in tcp_v6_syn_recv_sock()")
  fcd3d039fa ("tcp: make tcp_v{4,6}_send_check() static")
https://lore.kernel.org/aZ8PSFLzBrEU3I89@sirena.org.uk

drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c
drivers/net/ethernet/mellanox/mlx5/core/en/xsk/pool.c
  69050f8d6d ("treewide: Replace kmalloc with kmalloc_obj for non-scalar types")
  bf4afc53b7 ("Convert 'alloc_obj' family to use the new default GFP_KERNEL argument")
  8a96b9144f ("net/mlx5e: Alloc xsk channel param out of mlx5e_open_xsk()")

Adjacent changes:

net/netfilter/ipvs/ip_vs_ctl.c
  c59bd9e62e ("ipvs: use more counters to avoid service lookups")
  bf4afc53b7 ("Convert 'alloc_obj' family to use the new default GFP_KERNEL argument")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-26 10:23:00 -08:00
Eric Dumazet
2550def53b net: __lock_sock() can be static
After commit 6511882cdd ("mptcp: allocate fwd memory separately
on the rx and tx path") __lock_sock() can be static again.

Make sure __lock_sock() is not inlined, so that lock_sock_nested()
no longer needs a stack canary.

Add a noinline attribute on lock_sock_nested() so that calls
to lock_sock() from net/core/sock.c are not inlined,
none of them are fast path to deserve that:

 - sockopt_lock_sock()
 - sock_set_reuseport()
 - sock_set_reuseaddr()
 - sock_set_mark()
 - sock_set_keepalive()
 - sock_no_linger()
 - sock_bindtoindex()
 - sk_wait_data()
 - sock_set_rcvbuf()

$ scripts/bloat-o-meter -t vmlinux.old vmlinux
add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-312 (-312)
Function                                     old     new   delta
__lock_sock                                  192     188      -4
__lock_sock_fast                             239      86    -153
lock_sock_nested                             227      72    -155
Total: Before=24888707, After=24888395, chg -0.00%

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260223092716.3673939-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-24 16:30:33 -08:00
Linus Torvalds
bf4afc53b7 Convert 'alloc_obj' family to use the new default GFP_KERNEL argument
This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 17:09:51 -08:00
Kees Cook
69050f8d6d treewide: Replace kmalloc with kmalloc_obj for non-scalar types
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-21 01:02:28 -08:00
Eric Dumazet
ed9b70040d tcp: reduce tcp sockets size by one cache line
By default, when a kmem_cache is created with SLAB_TYPESAFE_BY_RCU,
slub has to use extra storage for the freelist pointer after each
object, because slub assumes that any bit in the object
can be used by RCU readers.

Because proto_register() is also using SLAB_HWCACHE_ALIGN,
this forces slub to use one extra cache line per object.

We can instead put the slub freelist anywhere in the object,
granted the concurrent RCU readers are not supposed to
use the pointer value.

Add a new (struct sock)sk_freeptr field, in an union
with sk_rcu: No RCU readers would need to look at sk_rcu,
which is only used at free phase.

Tested:

grep . /sys/kernel/slab/TCP/{object_size,slab_size,objs_per_slab}
grep . /sys/kernel/slab/TCPv6/{object_size,slab_size,objs_per_slab}

Before:

/sys/kernel/slab/TCP/object_size:2368
/sys/kernel/slab/TCP/slab_size:2432
/sys/kernel/slab/TCP/objs_per_slab:13

/sys/kernel/slab/TCPv6/object_size:2496
/sys/kernel/slab/TCPv6/slab_size:2560
/sys/kernel/slab/TCPv6/objs_per_slab:12

After this patch, we can pack one more TCPv6 object per slab,
and object_size == slab_size.

/sys/kernel/slab/TCP/object_size:2368
/sys/kernel/slab/TCP/slab_size:2368
/sys/kernel/slab/TCP/objs_per_slab:13

/sys/kernel/slab/TCPv6/object_size:2496
/sys/kernel/slab/TCPv6/slab_size:2496
/sys/kernel/slab/TCPv6/objs_per_slab:13

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260129153458.4163797-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-30 17:15:51 -08:00
Weiming Shi
2a71a1a8d0 net: sock: fix hardened usercopy panic in sock_recv_errqueue
skbuff_fclone_cache was created without defining a usercopy region,
[1] unlike skbuff_head_cache which properly whitelists the cb[] field.
[2] This causes a usercopy BUG() when CONFIG_HARDENED_USERCOPY is
enabled and the kernel attempts to copy sk_buff.cb data to userspace
via sock_recv_errqueue() -> put_cmsg().

The crash occurs when: 1. TCP allocates an skb using alloc_skb_fclone()
   (from skbuff_fclone_cache) [1]
2. The skb is cloned via skb_clone() using the pre-allocated fclone
[3] 3. The cloned skb is queued to sk_error_queue for timestamp
reporting 4. Userspace reads the error queue via recvmsg(MSG_ERRQUEUE)
5. sock_recv_errqueue() calls put_cmsg() to copy serr->ee from skb->cb
[4] 6. __check_heap_object() fails because skbuff_fclone_cache has no
   usercopy whitelist [5]

When cloned skbs allocated from skbuff_fclone_cache are used in the
socket error queue, accessing the sock_exterr_skb structure in skb->cb
via put_cmsg() triggers a usercopy hardening violation:

[    5.379589] usercopy: Kernel memory exposure attempt detected from SLUB object 'skbuff_fclone_cache' (offset 296, size 16)!
[    5.382796] kernel BUG at mm/usercopy.c:102!
[    5.383923] Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
[    5.384903] CPU: 1 UID: 0 PID: 138 Comm: poc_put_cmsg Not tainted 6.12.57 #7
[    5.384903] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[    5.384903] RIP: 0010:usercopy_abort+0x6c/0x80
[    5.384903] Code: 1a 86 51 48 c7 c2 40 15 1a 86 41 52 48 c7 c7 c0 15 1a 86 48 0f 45 d6 48 c7 c6 80 15 1a 86 48 89 c1 49 0f 45 f3 e8 84 27 88 ff <0f> 0b 490
[    5.384903] RSP: 0018:ffffc900006f77a8 EFLAGS: 00010246
[    5.384903] RAX: 000000000000006f RBX: ffff88800f0ad2a8 RCX: 1ffffffff0f72e74
[    5.384903] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff87b973a0
[    5.384903] RBP: 0000000000000010 R08: 0000000000000000 R09: fffffbfff0f72e74
[    5.384903] R10: 0000000000000003 R11: 79706f6372657375 R12: 0000000000000001
[    5.384903] R13: ffff88800f0ad2b8 R14: ffffea00003c2b40 R15: ffffea00003c2b00
[    5.384903] FS:  0000000011bc4380(0000) GS:ffff8880bf100000(0000) knlGS:0000000000000000
[    5.384903] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    5.384903] CR2: 000056aa3b8e5fe4 CR3: 000000000ea26004 CR4: 0000000000770ef0
[    5.384903] PKRU: 55555554
[    5.384903] Call Trace:
[    5.384903]  <TASK>
[    5.384903]  __check_heap_object+0x9a/0xd0
[    5.384903]  __check_object_size+0x46c/0x690
[    5.384903]  put_cmsg+0x129/0x5e0
[    5.384903]  sock_recv_errqueue+0x22f/0x380
[    5.384903]  tls_sw_recvmsg+0x7ed/0x1960
[    5.384903]  ? srso_alias_return_thunk+0x5/0xfbef5
[    5.384903]  ? schedule+0x6d/0x270
[    5.384903]  ? srso_alias_return_thunk+0x5/0xfbef5
[    5.384903]  ? mutex_unlock+0x81/0xd0
[    5.384903]  ? __pfx_mutex_unlock+0x10/0x10
[    5.384903]  ? __pfx_tls_sw_recvmsg+0x10/0x10
[    5.384903]  ? _raw_spin_lock_irqsave+0x8f/0xf0
[    5.384903]  ? _raw_read_unlock_irqrestore+0x20/0x40
[    5.384903]  ? srso_alias_return_thunk+0x5/0xfbef5

The crash offset 296 corresponds to skb2->cb within skbuff_fclones:
  - sizeof(struct sk_buff) = 232 - offsetof(struct sk_buff, cb) = 40 -
  offset of skb2.cb in fclones = 232 + 40 = 272 - crash offset 296 =
  272 + 24 (inside sock_exterr_skb.ee)

This patch uses a local stack variable as a bounce buffer to avoid the hardened usercopy check failure.

[1] https://elixir.bootlin.com/linux/v6.12.62/source/net/ipv4/tcp.c#L885
[2] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c#L5104
[3] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c#L5566
[4] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c#L5491
[5] https://elixir.bootlin.com/linux/v6.12.62/source/mm/slub.c#L5719

Fixes: 6d07d1cd30 ("usercopy: Restrict non-usercopy caches to size 0")
Reported-by: Xiang Mei <xmei5@asu.edu>
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251223203534.1392218-2-bestswngs@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-04 09:54:32 -08:00
Eric Dumazet
27e8257a86 net: move sk_dst_pending_confirm and sk_pacing_status to sock_read_tx group
These two fields are mostly read in TCP tx path, move them
in an more appropriate group for better cache locality.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20251124175013.1473655-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-25 19:28:29 -08:00
Paolo Abeni
075b19c211 net: factor-out _sk_charge() helper
Move out of __inet_accept() the code dealing charging newly
accepted socket to memcg. MPTCP will soon use it to on a per
subflow basis, in different contexts.

No functional changes intended.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Geliang Tang <geliang@kernel.org>
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-1-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:40 -08:00
Kees Cook
449f68f8ff net: Convert proto callbacks from sockaddr to sockaddr_unsized
Convert struct proto pre_connect(), connect(), bind(), and bind_add()
callback function prototypes from struct sockaddr to struct sockaddr_unsized.
This does not change per-implementation use of sockaddr for passing around
an arbitrarily sized sockaddr struct. Those will be addressed in future
patches.

Additionally removes the no longer referenced struct sockaddr from
include/net/inet_common.h.

No binary changes expected.

Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-5-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04 19:10:33 -08:00
Kees Cook
85cb0757d7 net: Convert proto_ops connect() callbacks to use sockaddr_unsized
Update all struct proto_ops connect() callback function prototypes from
"struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the
compiler about object sizes. Calls into struct proto handlers gain casts
that will be removed in the struct proto conversion patch.

No binary changes expected.

Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-3-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04 19:10:32 -08:00
Kees Cook
0e50474fa5 net: Convert proto_ops bind() callbacks to use sockaddr_unsized
Update all struct proto_ops bind() callback function prototypes from
"struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the
compiler about object sizes. Calls into struct proto handlers gain casts
that will be removed in the struct proto conversion patch.

No binary changes expected.

Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-2-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04 19:10:32 -08:00
Kuniyuki Iwashima
151b98d10e net: Add sk_clone().
sctp_accept() will use sk_clone_lock(), but it will be called
with the parent socket locked, and sctp_migrate() acquires the
child lock later.

Let's add no lock version of sk_clone_lock().

Note that lockdep complains if we simply use bh_lock_sock_nested().

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Link: https://patch.msgid.link/20251023231751.4168390-5-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-27 18:04:57 -07:00
Eric Dumazet
3ff9bcecce net: avoid extra access to sk->sk_wmem_alloc in sock_wfree()
UDP TX packets destructor is sock_wfree().

It suffers from a cache line bouncing in sock_def_write_space_wfree().

Instead of reading sk->sk_wmem_alloc after we just did an atomic RMW
on it, use __refcount_sub_and_test() to get the old value for free,
and pass the new value to sock_def_write_space_wfree().

Add __sock_writeable() helper.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20251017133712.2842665-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-10-21 15:56:21 +02:00
Kuniyuki Iwashima
b46ab63181 net: Introduce net.core.bypass_prot_mem sysctl.
If a socket has sk->sk_bypass_prot_mem flagged, the socket opts out
of the global protocol memory accounting.

Let's control the flag by a new sysctl knob.

The flag is written once during socket(2) and is inherited to child
sockets.

Tested with a script that creates local socket pairs and send()s a
bunch of data without recv()ing.

Setup:

  # mkdir /sys/fs/cgroup/test
  # echo $$ >> /sys/fs/cgroup/test/cgroup.procs
  # sysctl -q net.ipv4.tcp_mem="1000 1000 1000"
  # ulimit -n 524288

Without net.core.bypass_prot_mem, charged to tcp_mem & memcg

  # python3 pressure.py &
  # cat /sys/fs/cgroup/test/memory.stat | grep sock
  sock 22642688 <-------------------------------------- charged to memcg
  # cat /proc/net/sockstat| grep TCP
  TCP: inuse 2006 orphan 0 tw 0 alloc 2008 mem 5376 <-- charged to tcp_mem
  # ss -tn | head -n 5
  State Recv-Q Send-Q Local Address:Port  Peer Address:Port
  ESTAB 2000   0          127.0.0.1:34479    127.0.0.1:53188
  ESTAB 2000   0          127.0.0.1:34479    127.0.0.1:49972
  ESTAB 2000   0          127.0.0.1:34479    127.0.0.1:53868
  ESTAB 2000   0          127.0.0.1:34479    127.0.0.1:53554
  # nstat | grep Pressure || echo no pressure
  TcpExtTCPMemoryPressures        1                  0.0

With net.core.bypass_prot_mem=1, charged to memcg only:

  # sysctl -q net.core.bypass_prot_mem=1
  # python3 pressure.py &
  # cat /sys/fs/cgroup/test/memory.stat | grep sock
  sock 2757468160 <------------------------------------ charged to memcg
  # cat /proc/net/sockstat | grep TCP
  TCP: inuse 2006 orphan 0 tw 0 alloc 2008 mem 0 <- NOT charged to tcp_mem
  # ss -tn | head -n 5
  State Recv-Q Send-Q  Local Address:Port  Peer Address:Port
  ESTAB 111000 0           127.0.0.1:36019    127.0.0.1:49026
  ESTAB 110000 0           127.0.0.1:36019    127.0.0.1:45630
  ESTAB 110000 0           127.0.0.1:36019    127.0.0.1:44870
  ESTAB 111000 0           127.0.0.1:36019    127.0.0.1:45274
  # nstat | grep Pressure || echo no pressure
  no pressure

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://patch.msgid.link/20251014235604.3057003-4-kuniyu@google.com
2025-10-16 12:04:47 -07:00
Kuniyuki Iwashima
7c268eaeec net: Allow opt-out from global protocol memory accounting.
Some protocols (e.g., TCP, UDP) implement memory accounting for socket
buffers and charge memory to per-protocol global counters pointed to by
sk->sk_proto->memory_allocated.

Sometimes, system processes do not want that limitation.  For a similar
purpose, there is SO_RESERVE_MEM for sockets under memcg.

Also, by opting out of the per-protocol accounting, sockets under memcg
can avoid paying costs for two orthogonal memory accounting mechanisms.
A microbenchmark result is in the subsequent bpf patch.

Let's allow opt-out from the per-protocol memory accounting if
sk->sk_bypass_prot_mem is true.

sk->sk_bypass_prot_mem and sk->sk_prot are placed in the same cache
line, and sk_has_account() always fetches sk->sk_prot before accessing
sk->sk_bypass_prot_mem, so there is no extra cache miss for this patch.

The following patches will set sk->sk_bypass_prot_mem to true, and
then, the per-protocol memory accounting will be skipped.

Note that this does NOT disable memcg, but rather the per-protocol one.

Another option not to use the hole in struct sock_common is create
sk_prot variants like tcp_prot_bypass, but this would complicate
SOCKMAP logic, tcp_bpf_prots etc.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://patch.msgid.link/20251014235604.3057003-3-kuniyu@google.com
2025-10-16 12:04:47 -07:00
Eric Dumazet
d365c9bca3 net: control skb->ooo_okay from skb_set_owner_w()
15 years after Tom Herbert added skb->ooo_okay, only TCP transport
benefits from it.

We can support other transports directly from skb_set_owner_w().

If no other TX packet for this socket is in a host queue (qdisc, NIC queue)
there is no risk of self-inflicted reordering, we can set skb->ooo_okay.

This allows netdev_pick_tx() to choose a TX queue based on XPS settings,
instead of reusing the queue chosen at the time the first packet was sent
for connected sockets.

Tested:
  500 concurrent UDP_RR connected UDP flows, host with 32 TX queues,
  512 cpus, XPS setup.

  super_netperf 500 -t UDP_RR -H <host> -l 1000 -- -r 100,100 -Nn &

This patch saves between 10% and 20% of cycles, depending on how
process scheduler migrates threads among cpus.

Using following bpftrace script, we can see the effect on Qdisc/NIC tx queues
being better used (less cache line misses).

bpftrace -e '
k:__dev_queue_xmit { @start[cpu] = nsecs; }
kr:__dev_queue_xmit {
 if (@start[cpu]) {
    $delay = nsecs - @start[cpu];
    delete(@start[cpu]);
    @__dev_queue_xmit_ns = hist($delay);
 }
}
END { clear(@start); }'

Before:
@__dev_queue_xmit_ns:
[128, 256)             6 |                                                    |
[256, 512)        116283 |                                                    |
[512, 1K)        1888205 |@@@@@@@@@@@                                         |
[1K, 2K)         8106167 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@    |
[2K, 4K)         8699293 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
[4K, 8K)         2600676 |@@@@@@@@@@@@@@@                                     |
[8K, 16K)         721688 |@@@@                                                |
[16K, 32K)        122995 |                                                    |
[32K, 64K)         10639 |                                                    |
[64K, 128K)          119 |                                                    |
[128K, 256K)           1 |                                                    |

After:
@__dev_queue_xmit_ns:
[128, 256)             3 |                                                    |
[256, 512)        651112 |@@                                                  |
[512, 1K)        8109938 |@@@@@@@@@@@@@@@@@@@@@@@@@@                          |
[1K, 2K)        16081031 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
[2K, 4K)         2411692 |@@@@@@@                                             |
[4K, 8K)           98994 |                                                    |
[8K, 16K)           1536 |                                                    |
[16K, 32K)           587 |                                                    |
[32K, 64K)             2 |                                                    |

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20251013152234.842065-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-15 09:04:21 -07:00
Eric Dumazet
6ddb811a57 net: add SK_WMEM_ALLOC_BIAS constant
sk->sk_wmem_alloc is initialized to 1, and sk_wmem_alloc_get()
takes care of this initial value.

Add SK_WMEM_ALLOC_BIAS define to not spread this magic value.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20251013152234.842065-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-15 09:04:21 -07:00
Eric Dumazet
9303c3ced1 net: move sk->sk_err_soft and sk->sk_sndbuf
sk->sk_sndbuf is read-mostly in tx path, so move it from
sock_write_tx group to more appropriate sock_read_tx.

sk->sk_err_soft was not identified previously, but
is used from tcp_ack().

Move it to sock_write_tx group for better cache locality.

Also change tcp_ack() to clear sk->sk_err_soft only if needed.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250919204856.2977245-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-22 17:55:24 -07:00
Eric Dumazet
17b14d235f net: move sk_uid and sk_protocol to sock_read_tx
sk_uid and sk_protocol are read from inet6_csk_route_socket()
for each TCP transmit.

Also read from udpv6_sendmsg(), udp_sendmsg() and others.

Move them to sock_read_tx for better cache locality.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250919204856.2977245-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-22 17:55:24 -07:00
Eric Dumazet
9db27c8062 udp: add udp_drops_inc() helper
Generic sk_drops_inc() reads sk->sk_drop_counters.
We know the precise location for UDP sockets.

Move sk_drop_counters out of sock_read_rxtx
so that sock_write_rxtx starts at a cache line boundary.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250916160951.541279-9-edumazet@google.com
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18 10:17:10 +02:00
Eric Dumazet
16c610162d net: call cond_resched() less often in __release_sock()
While stress testing TCP I had unexpected retransmits and sack packets
when a single cpu receives data from multiple high-throughput flows.

super_netperf 4 -H srv -T,10 -l 3000 &

Tcpdump extract:

 00:00:00.000007 IP6 clnt > srv: Flags [.], seq 26062848:26124288, ack 1, win 66, options [nop,nop,TS val 651460834 ecr 3100749131], length 61440
 00:00:00.000006 IP6 clnt > srv: Flags [.], seq 26124288:26185728, ack 1, win 66, options [nop,nop,TS val 651460834 ecr 3100749131], length 61440
 00:00:00.000005 IP6 clnt > srv: Flags [P.], seq 26185728:26243072, ack 1, win 66, options [nop,nop,TS val 651460834 ecr 3100749131], length 57344
 00:00:00.000006 IP6 clnt > srv: Flags [.], seq 26243072:26304512, ack 1, win 66, options [nop,nop,TS val 651460844 ecr 3100749141], length 61440
 00:00:00.000005 IP6 clnt > srv: Flags [.], seq 26304512:26365952, ack 1, win 66, options [nop,nop,TS val 651460844 ecr 3100749141], length 61440
 00:00:00.000007 IP6 clnt > srv: Flags [P.], seq 26365952:26423296, ack 1, win 66, options [nop,nop,TS val 651460844 ecr 3100749141], length 57344
 00:00:00.000006 IP6 clnt > srv: Flags [.], seq 26423296:26484736, ack 1, win 66, options [nop,nop,TS val 651460853 ecr 3100749150], length 61440
 00:00:00.000005 IP6 clnt > srv: Flags [.], seq 26484736:26546176, ack 1, win 66, options [nop,nop,TS val 651460853 ecr 3100749150], length 61440
 00:00:00.000005 IP6 clnt > srv: Flags [P.], seq 26546176:26603520, ack 1, win 66, options [nop,nop,TS val 651460853 ecr 3100749150], length 57344
 00:00:00.003932 IP6 clnt > srv: Flags [P.], seq 26603520:26619904, ack 1, win 66, options [nop,nop,TS val 651464844 ecr 3100753141], length 16384
 00:00:00.006602 IP6 clnt > srv: Flags [.], seq 24862720:24866816, ack 1, win 66, options [nop,nop,TS val 651471419 ecr 3100759716], length 4096
 00:00:00.013000 IP6 clnt > srv: Flags [.], seq 24862720:24866816, ack 1, win 66, options [nop,nop,TS val 651484421 ecr 3100772718], length 4096
 00:00:00.000416 IP6 srv > clnt: Flags [.], ack 26619904, win 1393, options [nop,nop,TS val 3100773185 ecr 651484421,nop,nop,sack 1 {24862720:24866816}], length 0

After analysis, it appears this is because of the cond_resched()
call from  __release_sock().

When current thread is yielding, while still holding the TCP socket lock,
it might regain the cpu after a very long time.

Other peer TLP/RTO is firing (multiple times) and packets are retransmit,
while the initial copy is waiting in the socket backlog or receive queue.

In this patch, I call cond_resched() only once every 16 packets.

Modern TCP stack now spends less time per packet in the backlog,
especially because ACK are no longer sent (commit 133c4c0d37
"tcp: defer regular ACK while processing socket backlog")

Before:

clnt:/# nstat -n;sleep 10;nstat|egrep "TcpOutSegs|TcpRetransSegs|TCPFastRetrans|TCPTimeouts|Probes|TCPSpuriousRTOs|DSACK"
TcpOutSegs                      19046186           0.0
TcpRetransSegs                  1471               0.0
TcpExtTCPTimeouts               1397               0.0
TcpExtTCPLossProbes             1356               0.0
TcpExtTCPDSACKRecv              1352               0.0
TcpExtTCPSpuriousRTOs           114                0.0
TcpExtTCPDSACKRecvSegs          1352               0.0

After:

clnt:/# nstat -n;sleep 10;nstat|egrep "TcpOutSegs|TcpRetransSegs|TCPFastRetrans|TCPTimeouts|Probes|TCPSpuriousRTOs|DSACK"
TcpOutSegs                      19218936           0.0

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250903174811.1930820-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-04 19:16:51 -07:00
Jakub Kicinski
5ef04a7b06 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR (net-6.17-rc5).

No conflicts.

Adjacent changes:

include/net/sock.h
  c51613fa27 ("net: add sk->sk_drop_counters")
  5d6b58c932 ("net: lockless sock_i_ino()")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-04 13:33:00 -07:00
Eric Dumazet
5d6b58c932 net: lockless sock_i_ino()
Followup of commit c51da3f7a1 ("net: remove sock_i_uid()")

A recent syzbot report was the trigger for this change.

Over the years, we had many problems caused by the
read_lock[_bh](&sk->sk_callback_lock) in sock_i_uid().

We could fix smc_diag_dump_proto() or make a more radical move:

Instead of waiting for new syzbot reports, cache the socket
inode number in sk->sk_ino, so that we no longer
need to acquire sk->sk_callback_lock in sock_i_ino().

This makes socket dumps faster (one less cache line miss,
and two atomic ops avoided).

Prior art:

commit 25a9c8a443 ("netlink: Add __sock_i_ino() for __netlink_diag_dump().")
commit 4f9bf2a2f5 ("tcp: Don't acquire inet_listen_hashbucket::lock with disabled BH.")
commit efc3dbc374 ("rds: Make rds_sock_lock BH rather than IRQ safe.")

Fixes: d2d6422f8b ("x86: Allow to enable PREEMPT_RT.")
Reported-by: syzbot+50603c05bbdf4dfdaffa@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/68b73804.050a0220.3db4df.01d8.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20250902183603.740428-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-03 16:08:24 -07:00
Eric Dumazet
99a2ace61b net: use dst_dev_rcu() in sk_setup_caps()
Use RCU to protect accesses to dst->dev from sk_setup_caps()
and sk_dst_gso_max_size().

Also use dst_dev_rcu() in ip6_dst_mtu_maybe_forward(),
and ip_dst_mtu_maybe_forward().

ip4_dst_hoplimit() can use dst_dev_net_rcu().

Fixes: 4a6ce2b6f2 ("net: introduce a new function dst_dev_put()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250828195823.3958522-6-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-29 19:36:32 -07:00
Eric Dumazet
c51613fa27 net: add sk->sk_drop_counters
Some sockets suffer from heavy false sharing on sk->sk_drops,
and fields in the same cache line.

Add sk->sk_drop_counters to:

- move the drop counter(s) to dedicated cache lines.
- Add basic NUMA awareness to these drop counter(s).

Following patches will use this infrastructure for UDP and RAW sockets.

sk_clone_lock() is not yet ready, it would need to properly
set newsk->sk_drop_counters if we plan to use this for TCP sockets.

v2: used Paolo suggestion from https://lore.kernel.org/netdev/8f09830a-d83d-43c9-b36b-88ba0a23e9b2@redhat.com/

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250826125031.1578842-4-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-08-28 13:14:50 +02:00
Eric Dumazet
f86f42ed2c net: add sk_drops_read(), sk_drops_inc() and sk_drops_reset() helpers
We want to split sk->sk_drops in the future to reduce
potential contention on this field.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250826125031.1578842-2-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-08-28 13:14:50 +02:00
Eric Dumazet
a6d4f25888 net: set net.core.rmem_max and net.core.wmem_max to 4 MB
SO_RCVBUF and SO_SNDBUF have limited range today, unless
distros or system admins change rmem_max and wmem_max.

Even iproute2 uses 1 MB SO_RCVBUF which is capped by
the kernel.

Decouple [rw]mem_max and [rw]mem_default and increase
[rw]mem_max to 4 MB.

Before:

$ sysctl net.core.rmem_default net.core.rmem_max net.core.wmem_default net.core.wmem_max
net.core.rmem_default = 212992
net.core.rmem_max = 212992
net.core.wmem_default = 212992
net.core.wmem_max = 212992

After:

$ sysctl net.core.rmem_default net.core.rmem_max net.core.wmem_default net.core.wmem_max
net.core.rmem_default = 212992
net.core.rmem_max = 4194304
net.core.wmem_default = 212992
net.core.wmem_max = 4194304

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20250819174030.1986278-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-20 19:35:00 -07:00
Kuniyuki Iwashima
bf64002c94 net: Define sk_memcg under CONFIG_MEMCG.
Except for sk_clone_lock(), all accesses to sk->sk_memcg
is done under CONFIG_MEMCG.

As a bonus, let's define sk->sk_memcg under CONFIG_MEMCG.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Link: https://patch.msgid.link/20250815201712.1745332-11-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-19 19:20:59 -07:00
Kuniyuki Iwashima
bb178c6bc0 net-memcg: Pass struct sock to mem_cgroup_sk_(un)?charge().
We will store a flag in the lowest bit of sk->sk_memcg.

Then, we cannot pass the raw pointer to mem_cgroup_charge_skmem()
and mem_cgroup_uncharge_skmem().

Let's pass struct sock to the functions.

While at it, they are renamed to match other functions starting
with mem_cgroup_sk_.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Link: https://patch.msgid.link/20250815201712.1745332-9-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-19 19:20:59 -07:00
Kuniyuki Iwashima
43049b0db0 net-memcg: Introduce mem_cgroup_sk_enabled().
The socket memcg feature is enabled by a static key and
only works for non-root cgroup.

We check both conditions in many places.

Let's factorise it as a helper function.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Link: https://patch.msgid.link/20250815201712.1745332-8-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-19 19:20:59 -07:00