linux-stable.git/include, branch v6.6.141

bonding: 3ad: implement proper RCU rules for port->aggregator

2026-05-23T11:03:31+00:00

[ Upstream commit c4f050ce06c56cfb5993268af4a5cb66ed1cd04e ]

syzbot found a data-race in bond_3ad_get_active_agg_info /
bond_3ad_state_machine_handler [1] which hints at lack of proper
RCU implementation.

Add __rcu qualifier to port->aggregator, and add proper RCU API.

[1]

BUG: KCSAN: data-race in bond_3ad_get_active_agg_info / bond_3ad_state_machine_handler

write to 0xffff88813cf5c4b0 of 8 bytes by task 36 on cpu 0:
  ad_port_selection_logic drivers/net/bonding/bond_3ad.c:1659 [inline]
  bond_3ad_state_machine_handler+0x9d5/0x2d60 drivers/net/bonding/bond_3ad.c:2569
  process_one_work kernel/workqueue.c:3302 [inline]
  process_scheduled_works+0x4f0/0x9c0 kernel/workqueue.c:3385
  worker_thread+0x58a/0x780 kernel/workqueue.c:3466
  kthread+0x22a/0x280 kernel/kthread.c:436
  ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff88813cf5c4b0 of 8 bytes by task 22063 on cpu 1:
  __bond_3ad_get_active_agg_info drivers/net/bonding/bond_3ad.c:2858 [inline]
  bond_3ad_get_active_agg_info+0x8c/0x230 drivers/net/bonding/bond_3ad.c:2881
  bond_fill_info+0xe0f/0x10f0 drivers/net/bonding/bond_netlink.c:853
  rtnl_link_info_fill net/core/rtnetlink.c:906 [inline]
  rtnl_link_fill+0x1d7/0x4e0 net/core/rtnetlink.c:927
  rtnl_fill_ifinfo+0xf8e/0x1380 net/core/rtnetlink.c:2168
  rtmsg_ifinfo_build_skb+0x11c/0x1b0 net/core/rtnetlink.c:4453
  rtmsg_ifinfo_event net/core/rtnetlink.c:4486 [inline]
  rtmsg_ifinfo+0x6d/0x110 net/core/rtnetlink.c:4495
  __dev_notify_flags+0x76/0x390 net/core/dev.c:9790
  netif_change_flags+0xac/0xd0 net/core/dev.c:9823
  do_setlink+0x905/0x2950 net/core/rtnetlink.c:3180
  rtnl_group_changelink net/core/rtnetlink.c:3813 [inline]
  __rtnl_newlink net/core/rtnetlink.c:3981 [inline]
  rtnl_newlink+0xf55/0x1400 net/core/rtnetlink.c:4109
  rtnetlink_rcv_msg+0x64b/0x720 net/core/rtnetlink.c:6995
  netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2550
  rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:7022
  netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
  netlink_unicast+0x5a8/0x680 net/netlink/af_netlink.c:1344
  netlink_sendmsg+0x5c8/0x6f0 net/netlink/af_netlink.c:1894
  sock_sendmsg_nosec net/socket.c:787 [inline]
  __sock_sendmsg net/socket.c:802 [inline]
  ____sys_sendmsg+0x563/0x5b0 net/socket.c:2698
  ___sys_sendmsg+0x195/0x1e0 net/socket.c:2752
  __sys_sendmsg net/socket.c:2784 [inline]
  __do_sys_sendmsg net/socket.c:2789 [inline]
  __se_sys_sendmsg net/socket.c:2787 [inline]
  __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2787
  x64_sys_call+0x194c/0x3020 arch/x86/include/generated/asm/syscalls_64.h:47
  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
  do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000000 -> 0xffff88813cf5c400

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 22063 Comm: syz.0.31122 Tainted: G        W           syzkaller #0 PREEMPT(full)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026

Fixes: 47e91f56008b ("bonding: use RCU protection for 3ad xmit path")
Reported-by: syzbot+9bb2ff2a4ab9e17307e1@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/69f0a82f.050a0220.3aadc4.0000.GAE@google.com/
Signed-off-by: Eric Dumazet 
Cc: Jay Vosburgh 
Cc: Andrew Lunn 
Link: https://patch.msgid.link/20260428123207.3809211-1-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

bonding: print churn state via netlink

2026-05-23T11:03:30+00:00

[ Upstream commit 4916f2e2f3fc9aef289fcd07949301e5c29094c2 ]

Currently, the churn state is printed only in sysfs. Add netlink support
so users could get the state via netlink.

Signed-off-by: Hangbin Liu 
Link: https://patch.msgid.link/20260224020215.6012-1-liuhangbin@gmail.com
Signed-off-by: Paolo Abeni 
Stable-dep-of: c4f050ce06c5 ("bonding: 3ad: implement proper RCU rules for port->aggregator")
Signed-off-by: Sasha Levin

bonding: add support for per-port LACP actor priority

2026-05-23T11:03:30+00:00

[ Upstream commit 6b6dc81ee7e8ca87c71a533e1d69cf96a4f1e986 ]

Introduce a new netlink attribute 'actor_port_prio' to allow setting
the LACP actor port priority on a per-slave basis. This extends the
existing bonding infrastructure to support more granular control over
LACP negotiations.

The priority value is embedded in LACPDU packets and will be used by
subsequent patches to influence aggregator selection policies.

Signed-off-by: Hangbin Liu 
Link: https://patch.msgid.link/20250902064501.360822-2-liuhangbin@gmail.com
Signed-off-by: Paolo Abeni 
Stable-dep-of: c4f050ce06c5 ("bonding: 3ad: implement proper RCU rules for port->aggregator")
Signed-off-by: Sasha Levin

net: bonding: add broadcast_neighbor option for 802.3ad

2026-05-23T11:03:30+00:00

[ Upstream commit ce7a381697cb3958ffe0b45e5028ac69444e9288 ]

Stacking technology is a type of technology used to expand ports on
Ethernet switches. It is widely used as a common access method in
large-scale Internet data center architectures. Years of practice
have proved that stacking technology has advantages and disadvantages
in high-reliability network architecture scenarios. For instance,
in stacking networking arch, conventional switch system upgrades
require multiple stacked devices to restart at the same time.
Therefore, it is inevitable that the business will be interrupted
for a while. It is for this reason that "no-stacking" in data centers
has become a trend. Additionally, when the stacking link connecting
the switches fails or is abnormal, the stack will split. Although it is
not common, it still happens in actual operation. The problem is that
after the split, it is equivalent to two switches with the same
configuration appearing in the network, causing network configuration
conflicts and ultimately interrupting the services carried by the
stacking system.

To improve network stability, "non-stacking" solutions have been
increasingly adopted, particularly by public cloud providers and
tech companies like Alibaba, Tencent, and Didi. "non-stacking" is
a method of mimicing switch stacking that convinces a LACP peer,
bonding in this case, connected to a set of "non-stacked" switches
that all of its ports are connected to a single switch
(i.e., LACP aggregator), as if those switches were stacked. This
enables the LACP peer's ports to aggregate together, and requires
(a) special switch configuration, described in the linked article,
and (b) modifications to the bonding 802.3ad (LACP) mode to send
all ARP/ND packets across all ports of the active aggregator.

Note that, with multiple aggregators, the current broadcast mode
logic will send only packets to the selected aggregator(s).

 +-----------+   +-----------+
 |  switch1  |   |  switch2  |
 +-----------+   +-----------+
         ^           ^
         |           |
      +-----------------+
      |   bond4 lacp    |
      +-----------------+
         |           |
         | NIC1      | NIC2
      +-----------------+
      |     server      |
      +-----------------+

- https://www.ruijie.com/fr-fr/support/tech-gallery/de-stack-data-center-network-architecture/

Cc: Jay Vosburgh 
Cc: "David S. Miller" 
Cc: Eric Dumazet 
Cc: Jakub Kicinski 
Cc: Paolo Abeni 
Cc: Simon Horman 
Cc: Jonathan Corbet 
Cc: Andrew Lunn 
Cc: Steven Rostedt 
Cc: Masami Hiramatsu 
Cc: Mathieu Desnoyers 
Cc: Nikolay Aleksandrov 
Signed-off-by: Tonghao Zhang 
Signed-off-by: Zengbing Tu 
Link: https://patch.msgid.link/84d0a044514157bb856a10b6d03a1028c4883561.1751031306.git.tonghao@bamaicloud.com
Signed-off-by: Paolo Abeni 
Stable-dep-of: c4f050ce06c5 ("bonding: 3ad: implement proper RCU rules for port->aggregator")
Signed-off-by: Sasha Levin

ipv6: rename and move ip6_dst_lookup_tunnel()

2026-05-23T11:03:30+00:00

[ Upstream commit fc47e86dbfb75a864c0c9dd8e78affb6506296bb ]

At the moment ip6_dst_lookup_tunnel() is used only by bareudp.
Ideally, other UDP tunnel implementations should use it, but to do so
the function needs to accept new parameters that are specific for UDP
tunnels, such as the ports.

Prepare for these changes by renaming the function to
udp_tunnel6_dst_lookup() and move it to file
net/ipv6/ip6_udp_tunnel.c.

This is similar to what already done for IPv4 in commit bf3fcbf7e7a0
("ipv4: rename and move ip_route_output_tunnel()").

Suggested-by: Guillaume Nault 
Signed-off-by: Beniamino Galvani 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Stable-dep-of: aa6c6d9ee064 ("bareudp: fix NULL pointer dereference in bareudp_fill_metadata_dst()")
Signed-off-by: Sasha Levin

ipv4: add new arguments to udp_tunnel_dst_lookup()

2026-05-23T11:03:29+00:00

[ Upstream commit 72fc68c6356b663a8763f02d9b0ec773d59a4949 ]

We want to make the function more generic so that it can be used by
other UDP tunnel implementations such as geneve and vxlan. To do that,
add the following arguments:

 - source and destination UDP port;
 - ifindex of the output interface, needed by vxlan;
 - the tos, because in some cases it is not taken from struct
   ip_tunnel_info (for example, when it's inherited from the inner
   packet);
 - the dst cache, because not all tunnel types (e.g. vxlan) want to
   use the one from struct ip_tunnel_info.

With these parameters, the function no longer needs the full struct
ip_tunnel_info as argument and we can pass only the relevant part of
it (struct ip_tunnel_key).

Suggested-by: Guillaume Nault 
Signed-off-by: Beniamino Galvani 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Stable-dep-of: aa6c6d9ee064 ("bareudp: fix NULL pointer dereference in bareudp_fill_metadata_dst()")
Signed-off-by: Sasha Levin

ipv4: remove "proto" argument from udp_tunnel_dst_lookup()

2026-05-23T11:03:29+00:00

[ Upstream commit 78f3655adcb52412275f282267ee771421731632 ]

The function is now UDP-specific, the protocol is always IPPROTO_UDP.

Suggested-by: Guillaume Nault 
Signed-off-by: Beniamino Galvani 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Stable-dep-of: aa6c6d9ee064 ("bareudp: fix NULL pointer dereference in bareudp_fill_metadata_dst()")
Signed-off-by: Sasha Levin

ipv4: rename and move ip_route_output_tunnel()

2026-05-23T11:03:29+00:00

[ Upstream commit bf3fcbf7e7a08015d3b169bad6281b29d45c272d ]

At the moment ip_route_output_tunnel() is used only by bareudp.
Ideally, other UDP tunnel implementations should use it, but to do so
the function needs to accept new parameters that are specific for UDP
tunnels, such as the ports.

Prepare for these changes by renaming the function to
udp_tunnel_dst_lookup() and move it to file
net/ipv4/udp_tunnel_core.c.

Suggested-by: Guillaume Nault 
Signed-off-by: Beniamino Galvani 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Stable-dep-of: aa6c6d9ee064 ("bareudp: fix NULL pointer dereference in bareudp_fill_metadata_dst()")
Signed-off-by: Sasha Levin

cdrom, scsi: sr: propagate read-only status to block layer via set_disk_ro()

2026-05-23T11:03:27+00:00

[ Upstream commit 0898a817621a2f0cddca8122d9b974003fe5036d ]

The cdrom core never calls set_disk_ro() for a registered device, so
BLKROGET on a CD-ROM device always returns 0 (writable), even when the
drive has no write capabilities and writes will inevitably fail. This
causes problems for userspace that relies on BLKROGET to determine
whether a block device is read-only. For example, systemd's loop device
setup uses BLKROGET to decide whether to create a loop device with
LO_FLAGS_READ_ONLY. Without the read-only flag, writes pass through the
loop device to the CD-ROM and fail with I/O errors. systemd-fsck
similarly checks BLKROGET to decide whether to run fsck in no-repair
mode (-n).

The write-capability bits in cdi->mask come from two different sources:
CDC_DVD_RAM and CDC_CD_RW are populated by the driver from the MODE
SENSE capabilities page (page 0x2A) before register_cdrom() is called,
while CDC_MRW_W and CDC_RAM require the MMC GET CONFIGURATION command
and were only probed by cdrom_open_write() at device open time. This
meant that any attempt to compute the writable state from the full
mask at probe time was incorrect, because the GET CONFIGURATION bits
were still unset (and cdi->mask is initialized such that capabilities
are assumed present).

Fix this by factoring the GET CONFIGURATION probing out of
cdrom_open_write() into a new exported helper,
cdrom_probe_write_features(), and having sr call it from sr_probe()
right after get_capabilities() has populated the MODE SENSE bits.
register_cdrom() then calls set_disk_ro() based on the full
write-capability mask (CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)
so the block layer reflects the drive's actual write support. The
feature queries used (CDF_MRW and CDF_RWRT via GET CONFIGURATION with
RT=00) report drive-level capabilities that are persistent across
media, so a single probe before register_cdrom() is sufficient and the
redundant probe at open time is dropped.

With set_disk_ro() now accurate, the long-vestigial cd->writeable flag
in sr can go: get_capabilities() used to set cd->writeable based on
the same four mask bits, but because CDC_MRW_W and CDC_RAM default to
"capability present" in cdi->mask and aren't touched by MODE SENSE,
the condition that gated cd->writeable was always true, making it
unconditionally 1. Replace the corresponding gate in sr_init_command()
with get_disk_ro(cd->disk), which turns a previously no-op check into
a real one and also catches kernel-internal bio writers that bypass
blkdev_write_iter()'s bdev_read_only() check.

The sd driver (SCSI disks) does not have this problem because it
checks the MODE SENSE Write Protect bit and calls set_disk_ro()
accordingly. The sr driver cannot use the same approach because the
MMC specification does not define the WP bit in the MODE SENSE
device-specific parameter byte for CD-ROM devices.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Daan De Meyer 
Reviewed-by: Phillip Potter 
Reviewed-by: Martin K. Petersen 
Signed-off-by: Phillip Potter 
Link: https://patch.msgid.link/20260427210139.1400-2-phil@philpotter.co.uk
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

net/sched: sch_pie: annotate data-races in pie_dump_stats()

2026-05-23T11:03:25+00:00

[ Upstream commit 5154561d9b119f781249f8e845fecf059b38b483 ]

pie_dump_stats() only runs with RTNL held,
reading fields that can be changed in qdisc fast path.

Add READ_ONCE()/WRITE_ONCE() annotations.

Alternative would be to acquire the qdisc spinlock, but our long-term
goal is to make qdisc dump operations lockless as much as we can.

tc_pie_xstats fields don't need to be latched atomically,
otherwise this bug would have been caught earlier.

Fixes: edb09eb17ed8 ("net: sched: do not acquire qdisc spinlock in qdisc/class stats dump")
Signed-off-by: Eric Dumazet 
Reviewed-by: Jamal Hadi Salim 
Link: https://patch.msgid.link/20260421142944.4009941-1-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin