Previously, when reducing a qdisc's limit via the ->change() operation, only
the main skb queue was trimmed, potentially leaving packets in the gso_skb
list. This could result in NULL pointer dereference when we only check
sch->limit against sch->q.qlen.

This patch introduces a new helper, qdisc_dequeue_internal(), which ensures
both the gso_skb list and the main queue are properly flushed when trimming
excess packets. All relevant qdiscs (codel, fq, fq_codel, fq_pie, hhf, pie)
are updated to use this helper in their ->change() routines.

Fixes: 76e3cc126bb2 ("codel: Controlled Delay AQM")
Fixes: 4b549a2ef4be ("fq_codel: Fair Queue Codel AQM")
Fixes: afe4fd062416 ("pkt_sched: fq: Fair Queue packet scheduler")
Fixes: ec97ecf1ebe4 ("net: sched: add Flow Queue PIE packet scheduler")
Fixes: 10239edf86f1 ("net-qdisc-hhf: Heavy-Hitter Filter (HHF) qdisc")
Fixes: d4b36210c2e6 ("net: pkt_sched: PIE AQM scheme")
Reported-by: Will <willsroot@protonmail.com>
Reported-by: Savy <savy@syst3mfailure.io>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Luiz Augusto von Dentz says:

====================
bluetooth pull request for net:

 - MGMT: Fix MGMT_OP_ADD_DEVICE invalid device flags
 - hci_event: Fix not using key encryption size when its known

* tag 'for-net-2025-05-08' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth:
  Bluetooth: hci_event: Fix not using key encryption size when its known
  Bluetooth: MGMT: Fix MGMT_OP_ADD_DEVICE invalid device flags
====================

Link: https://patch.msgid.link/20250508150927.385675-1-luiz.dentz@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This fixes the regression introduced by 50c1241e6a8a ("Bluetooth: l2cap:
Check encryption key size on incoming connection") introduced a check for
l2cap_check_enc_key_size which checks for hcon->enc_key_size which may
not be initialized if HCI_OP_READ_ENC_KEY_SIZE is still pending.

If the key encryption size is known, due previously reading it using
HCI_OP_READ_ENC_KEY_SIZE, then store it as part of link_key/smp_ltk
structures so the next time the encryption is changed their values are
used as conn->enc_key_size thus avoiding the racing against
HCI_OP_READ_ENC_KEY_SIZE.

Now that the enc_size is stored as part of key the information the code
then attempts to check that there is no downgrade of security if
HCI_OP_READ_ENC_KEY_SIZE returns a value smaller than what has been
previously stored.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=220061
Link: https://bugzilla.kernel.org/show_bug.cgi?id=220063
Fixes: 522e9ed157e3 ("Bluetooth: l2cap: Check encryption key size on incoming connection")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Older drivers and drivers with lower queue counts often have a static
array of queues, rather than allocating structs for each queue on demand.
Add a helper for adding up qstats from a queue range. Expectation is
that driver will pass a queue range [netdev->real_num_*x_queues, MAX).
It was tempting to always use num_*x_queues as the end, but virtio
seems to clamp its queue count after allocating the netdev. And this
way we can trivaly reuse the helper for [0, real_..).

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20250507003221.823267-2-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

BIG Create Sync requires the command to just generates a status so this
makes use of __hci_cmd_sync_status_sk to wait for
HCI_EVT_LE_BIG_SYNC_ESTABLISHED, also because of this chance it is not
longer necessary to use a custom method to serialize the process of
creating the BIG sync since the cmd_work_sync itself ensures only one
command would be pending which now awaits for
HCI_EVT_LE_BIG_SYNC_ESTABLISHED before proceeding to next connection.

Fixes: 42ecf1947135 ("Bluetooth: ISO: Do not emit LE BIG Create Sync if previous is pending")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Broadcast Receiver requires creating PA sync but the command just
generates a status so this makes use of __hci_cmd_sync_status_sk to wait
for HCI_EV_LE_PA_SYNC_ESTABLISHED, also because of this chance it is not
longer necessary to use a custom method to serialize the process of
creating the PA sync since the cmd_work_sync itself ensures only one
command would be pending which now awaits for
HCI_EV_LE_PA_SYNC_ESTABLISHED before proceeding to next connection.

Fixes: 4a5e0ba68676 ("Bluetooth: ISO: Do not emit LE PA Create Sync if previous is pending")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bring back previous offset calculation behaviour
in AF_XDP unaligned umem mode.

In unaligned mode, upper 16 bits should contain
data offset, lower 48 bits should contain
only specific chunk location without offset.

Remove pool->headroom duplication into 48bit address.

Signed-off-by: Eryk Kubanski <e.kubanski@partner.samsung.com>
Fixes: bea14124bacb ("xsk: Get rid of xdp_buff_xsk::orig_addr")
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://patch.msgid.link/20250416112925.7501-1-e.kubanski@partner.samsung.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Move rx_lock from xsk_socket to xsk_buff_pool.
Fix synchronization for shared umem mode in
generic RX path where multiple sockets share
single xsk_buff_pool.

RX queue is exclusive to xsk_socket, while FILL
queue can be shared between multiple sockets.
This could result in race condition where two
CPU cores access RX path of two different sockets
sharing the same umem.

Protect both queues by acquiring spinlock in shared
xsk_buff_pool.

Lock contention may be minimized in the future by some
per-thread FQ buffering.

It's safe and necessary to move spin_lock_bh(rx_lock)
after xsk_rcv_check():
* xs->pool and spinlock_init is synchronized by
  xsk_bind() -> xsk_is_bound() memory barriers.
* xsk_rcv_check() may return true at the moment
  of xsk_release() or xsk_unbind_dev(),
  however this will not cause any data races or
  race conditions. xsk_unbind_dev() removes xdp
  socket from all maps and waits for completion
  of all outstanding rx operations. Packets in
  RX path will either complete safely or drop.

Signed-off-by: Eryk Kubanski <e.kubanski@partner.samsung.com>
Fixes: bf0bdd1343efb ("xdp: fix race on generic receive path")
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://patch.msgid.link/20250416101908.10919-1-e.kubanski@partner.samsung.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Before commit 40867d74c374 ("net: Add l3mdev index to flow struct and
avoid oif reset for port devices") it was possible to use FIB rules to
match on a L3 domain. This was done by having a FIB rule match on iif /
oif being a L3 master device. It worked because prior to the FIB rule
lookup the iif / oif fields in the flow structure were reset to the
index of the L3 master device to which the input / output device was
enslaved to.

The above scheme made it impossible to match on the original input /
output device. Therefore, cited commit stopped overwriting the iif / oif
fields in the flow structure and instead stored the index of the
enslaving L3 master device in a new field ('flowi_l3mdev') in the flow
structure.

While the change enabled new use cases, it broke the original use case
of matching on a L3 domain. Fix this by interpreting the iif / oif
matching on a L3 master device as a match against the L3 domain. In
other words, if the iif / oif in the FIB rule points to a L3 master
device, compare the provided index against 'flowi_l3mdev' rather than
'flowi_{i,o}if'.

Before cited commit, a FIB rule that matched on 'iif vrf1' would only
match incoming traffic from devices enslaved to 'vrf1'. With the
proposed change (i.e., comparing against 'flowi_l3mdev'), the rule would
also match traffic originating from a socket bound to 'vrf1'. Avoid that
by adding a new flow flag ('FLOWI_FLAG_L3MDEV_OIF') that indicates if
the L3 domain was derived from the output interface or the input
interface (when not set) and take this flag into account when evaluating
the FIB rule against the flow structure.

Avoid unnecessary checks in the data path by detecting that a rule
matches on a L3 master device when the rule is installed and marking it
as such.

Tested using the following script [1].

Output before 40867d74c374 (v5.4.291):

default dev dummy1 table 100 scope link
default dev dummy1 table 200 scope link

Output after 40867d74c374:

default dev dummy1 table 300 scope link
default dev dummy1 table 300 scope link

Output with this patch:

default dev dummy1 table 100 scope link
default dev dummy1 table 200 scope link

[1]
 #!/bin/bash

 ip link add name vrf1 up type vrf table 10
 ip link add name dummy1 up master vrf1 type dummy

 sysctl -wq net.ipv4.conf.all.forwarding=1
 sysctl -wq net.ipv4.conf.all.rp_filter=0

 ip route add table 100 default dev dummy1
 ip route add table 200 default dev dummy1
 ip route add table 300 default dev dummy1

 ip rule add prio 0 oif vrf1 table 100
 ip rule add prio 1 iif vrf1 table 200
 ip rule add prio 2 table 300

 ip route get 192.0.2.1 oif dummy1 fibmatch
 ip route get 192.0.2.1 iif dummy1 from 198.51.100.1 fibmatch

Fixes: 40867d74c374 ("net: Add l3mdev index to flow struct and avoid oif reset for port devices")
Reported-by: hanhuihui <hanhuihui5@huawei.com>
Closes: https://lore.kernel.org/netdev/ec671c4f821a4d63904d0da15d604b75@huawei.com/
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250414172022.242991-2-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Pull networking fixes from Paolo Abeni:
 "Including fixes from netfilter.

  Current release - regressions:

    - core: hold instance lock during NETDEV_CHANGE

    - rtnetlink: fix bad unlock balance in do_setlink()

    - ipv6:
       - fix null-ptr-deref in addrconf_add_ifaddr()
       - align behavior across nexthops during path selection

  Previous releases - regressions:

    - sctp: prevent transport UaF in sendmsg

    - mptcp: only inc MPJoinAckHMacFailure for HMAC failures

  Previous releases - always broken:

    - sched:
       - make ->qlen_notify() idempotent
       - ensure sufficient space when sending filter netlink notifications
       - sch_sfq: really don't allow 1 packet limit

    - netfilter: fix incorrect avx2 match of 5th field octet

    - tls: explicitly disallow disconnect

    - eth: octeontx2-pf: fix VF root node parent queue priority"

* tag 'net-6.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (38 commits)
  ethtool: cmis_cdb: Fix incorrect read / write length extension
  selftests: netfilter: add test case for recent mismatch bug
  nft_set_pipapo: fix incorrect avx2 match of 5th field octet
  net: ppp: Add bound checking for skb data on ppp_sync_txmung
  net: Fix null-ptr-deref by sock_lock_init_class_and_name() and rmmod.
  ipv6: Align behavior across nexthops during path selection
  net: phy: allow MDIO bus PM ops to start/stop state machine for phylink-controlled PHY
  net: phy: move phy_link_change() prior to mdio_bus_phy_may_suspend()
  selftests/tc-testing: sfq: check that a derived limit of 1 is rejected
  net_sched: sch_sfq: move the limit validation
  net_sched: sch_sfq: use a temporary work area for validating configuration
  net: libwx: handle page_pool_dev_alloc_pages error
  selftests: mptcp: validate MPJoin HMacFailure counters
  mptcp: only inc MPJoinAckHMacFailure for HMAC failures
  rtnetlink: Fix bad unlock balance in do_setlink().
  net: ethtool: Don't call .cleanup_data when prepare_data fails
  tc: Ensure we have enough buffer space when sending filter netlink notifications
  net: libwx: Fix the wrong Rx descriptor field
  octeontx2-pf: qos: fix VF root node parent queue index
  selftests: tls: check that disconnect does nothing
  ...