linux-stable.git/net/core/dev.c, branch linux-6.16.y Linux kernel stable tree net: gso: Forbid IPv6 TSO with extensions on devices with only IPV6_CSUM 2025-08-28T14:34:46+00:00 Jakub Ramaseuski jramaseu@redhat.com 2025-08-14T10:51:19+00:00 794ddbb7b63b6828c75967b9bcd43b086716e7a1 [ Upstream commit 864e3396976ef41de6cc7bc366276bf4e084fff2 ] When performing Generic Segmentation Offload (GSO) on an IPv6 packet that contains extension headers, the kernel incorrectly requests checksum offload if the egress device only advertises NETIF_F_IPV6_CSUM feature, which has a strict contract: it supports checksum offload only for plain TCP or UDP over IPv6 and explicitly does not support packets with extension headers. The current GSO logic violates this contract by failing to disable the feature for packets with extension headers, such as those used in GREoIPv6 tunnels. This violation results in the device being asked to perform an operation it cannot support, leading to a `skb_warn_bad_offload` warning and a collapse of network throughput. While device TSO/USO is correctly bypassed in favor of software GSO for these packets, the GSO stack must be explicitly told not to request checksum offload. Mask NETIF_F_IPV6_CSUM, NETIF_F_TSO6 and NETIF_F_GSO_UDP_L4 in gso_features_check if the IPv6 header contains extension headers to compute checksum in software. The exception is a BIG TCP extension, which, as stated in commit 68e068cabd2c6c53 ("net: reenable NETIF_F_IPV6_CSUM offload for BIG TCP packets"): "The feature is only enabled on devices that support BIG TCP TSO. The header is only present for PF_PACKET taps like tcpdump, and not transmitted by physical devices." kernel log output (truncated): WARNING: CPU: 1 PID: 5273 at net/core/dev.c:3535 skb_warn_bad_offload+0x81/0x140 ... Call Trace: <TASK> skb_checksum_help+0x12a/0x1f0 validate_xmit_skb+0x1a3/0x2d0 validate_xmit_skb_list+0x4f/0x80 sch_direct_xmit+0x1a2/0x380 __dev_xmit_skb+0x242/0x670 __dev_queue_xmit+0x3fc/0x7f0 ip6_finish_output2+0x25e/0x5d0 ip6_finish_output+0x1fc/0x3f0 ip6_tnl_xmit+0x608/0xc00 [ip6_tunnel] ip6gre_tunnel_xmit+0x1c0/0x390 [ip6_gre] dev_hard_start_xmit+0x63/0x1c0 __dev_queue_xmit+0x6d0/0x7f0 ip6_finish_output2+0x214/0x5d0 ip6_finish_output+0x1fc/0x3f0 ip6_xmit+0x2ca/0x6f0 ip6_finish_output+0x1fc/0x3f0 ip6_xmit+0x2ca/0x6f0 inet6_csk_xmit+0xeb/0x150 __tcp_transmit_skb+0x555/0xa80 tcp_write_xmit+0x32a/0xe90 tcp_sendmsg_locked+0x437/0x1110 tcp_sendmsg+0x2f/0x50 ... skb linear: 00000000: e4 3d 1a 7d ec 30 e4 3d 1a 7e 5d 90 86 dd 60 0e skb linear: 00000010: 00 0a 1b 34 3c 40 20 11 00 00 00 00 00 00 00 00 skb linear: 00000020: 00 00 00 00 00 12 20 11 00 00 00 00 00 00 00 00 skb linear: 00000030: 00 00 00 00 00 11 2f 00 04 01 04 01 01 00 00 00 skb linear: 00000040: 86 dd 60 0e 00 0a 1b 00 06 40 20 23 00 00 00 00 skb linear: 00000050: 00 00 00 00 00 00 00 00 00 12 20 23 00 00 00 00 skb linear: 00000060: 00 00 00 00 00 00 00 00 00 11 bf 96 14 51 13 f9 skb linear: 00000070: ae 27 a0 a8 2b e3 80 18 00 40 5b 6f 00 00 01 01 skb linear: 00000080: 08 0a 42 d4 50 d5 4b 70 f8 1a Fixes: 04c20a9356f283da ("net: skip offload for NETIF_F_IPV6_CSUM if ipv6 header contains extension") Reported-by: Tianhao Zhao <tizhao@redhat.com> Suggested-by: Michal Schmidt <mschmidt@redhat.com> Suggested-by: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Signed-off-by: Jakub Ramaseuski <jramaseu@redhat.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20250814105119.1525687-1-jramaseu@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 864e3396976ef41de6cc7bc366276bf4e084fff2 ]

When performing Generic Segmentation Offload (GSO) on an IPv6 packet that
contains extension headers, the kernel incorrectly requests checksum offload
if the egress device only advertises NETIF_F_IPV6_CSUM feature, which has
a strict contract: it supports checksum offload only for plain TCP or UDP
over IPv6 and explicitly does not support packets with extension headers.
The current GSO logic violates this contract by failing to disable the feature
for packets with extension headers, such as those used in GREoIPv6 tunnels.

This violation results in the device being asked to perform an operation
it cannot support, leading to a `skb_warn_bad_offload` warning and a collapse
of network throughput. While device TSO/USO is correctly bypassed in favor
of software GSO for these packets, the GSO stack must be explicitly told not
to request checksum offload.

Mask NETIF_F_IPV6_CSUM, NETIF_F_TSO6 and NETIF_F_GSO_UDP_L4
in gso_features_check if the IPv6 header contains extension headers to compute
checksum in software.

The exception is a BIG TCP extension, which, as stated in commit
68e068cabd2c6c53 ("net: reenable NETIF_F_IPV6_CSUM offload for BIG TCP packets"):
"The feature is only enabled on devices that support BIG TCP TSO.
The header is only present for PF_PACKET taps like tcpdump,
and not transmitted by physical devices."

kernel log output (truncated):
WARNING: CPU: 1 PID: 5273 at net/core/dev.c:3535 skb_warn_bad_offload+0x81/0x140
...
Call Trace:
 <TASK>
 skb_checksum_help+0x12a/0x1f0
 validate_xmit_skb+0x1a3/0x2d0
 validate_xmit_skb_list+0x4f/0x80
 sch_direct_xmit+0x1a2/0x380
 __dev_xmit_skb+0x242/0x670
 __dev_queue_xmit+0x3fc/0x7f0
 ip6_finish_output2+0x25e/0x5d0
 ip6_finish_output+0x1fc/0x3f0
 ip6_tnl_xmit+0x608/0xc00 [ip6_tunnel]
 ip6gre_tunnel_xmit+0x1c0/0x390 [ip6_gre]
 dev_hard_start_xmit+0x63/0x1c0
 __dev_queue_xmit+0x6d0/0x7f0
 ip6_finish_output2+0x214/0x5d0
 ip6_finish_output+0x1fc/0x3f0
 ip6_xmit+0x2ca/0x6f0
 ip6_finish_output+0x1fc/0x3f0
 ip6_xmit+0x2ca/0x6f0
 inet6_csk_xmit+0xeb/0x150
 __tcp_transmit_skb+0x555/0xa80
 tcp_write_xmit+0x32a/0xe90
 tcp_sendmsg_locked+0x437/0x1110
 tcp_sendmsg+0x2f/0x50
...
skb linear:   00000000: e4 3d 1a 7d ec 30 e4 3d 1a 7e 5d 90 86 dd 60 0e
skb linear:   00000010: 00 0a 1b 34 3c 40 20 11 00 00 00 00 00 00 00 00
skb linear:   00000020: 00 00 00 00 00 12 20 11 00 00 00 00 00 00 00 00
skb linear:   00000030: 00 00 00 00 00 11 2f 00 04 01 04 01 01 00 00 00
skb linear:   00000040: 86 dd 60 0e 00 0a 1b 00 06 40 20 23 00 00 00 00
skb linear:   00000050: 00 00 00 00 00 00 00 00 00 12 20 23 00 00 00 00
skb linear:   00000060: 00 00 00 00 00 00 00 00 00 11 bf 96 14 51 13 f9
skb linear:   00000070: ae 27 a0 a8 2b e3 80 18 00 40 5b 6f 00 00 01 01
skb linear:   00000080: 08 0a 42 d4 50 d5 4b 70 f8 1a

Fixes: 04c20a9356f283da ("net: skip offload for NETIF_F_IPV6_CSUM if ipv6 header contains extension")
Reported-by: Tianhao Zhao <tizhao@redhat.com>
Suggested-by: Michal Schmidt <mschmidt@redhat.com>
Suggested-by: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Signed-off-by: Jakub Ramaseuski <jramaseu@redhat.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250814105119.1525687-1-jramaseu@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
net: annotate data-races around cleanup_net_task 2025-06-05T15:02:26+00:00 Eric Dumazet edumazet@google.com 2025-06-04T09:39:28+00:00 535caaca921c653b1f9838fbd5c4e9494cafc3d9 from_cleanup_net() reads cleanup_net_task locklessly. Add READ_ONCE()/WRITE_ONCE() annotations to avoid a potential KCSAN warning, even if the race is harmless. Fixes: 0734d7c3d93c ("net: expedite synchronize_net() for cleanup_net()") Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Link: https://patch.msgid.link/20250604093928.1323333-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
from_cleanup_net() reads cleanup_net_task locklessly.

Add READ_ONCE()/WRITE_ONCE() annotations to avoid
a potential KCSAN warning, even if the race is harmless.

Fixes: 0734d7c3d93c ("net: expedite synchronize_net() for cleanup_net()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://patch.msgid.link/20250604093928.1323333-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
hv_netvsc: fix potential deadlock in netvsc_vf_setxdp() 2025-05-31T02:31:25+00:00 Saurabh Sengar ssengar@linux.microsoft.com 2025-05-29T10:18:30+00:00 3ec523304976648b45a3eef045e97d17122ff1b2 The MANA driver's probe registers netdevice via the following call chain: mana_probe() register_netdev() register_netdevice() register_netdevice() calls notifier callback for netvsc driver, holding the netdev mutex via netdev_lock_ops(). Further this netvsc notifier callback end up attempting to acquire the same lock again in dev_xdp_propagate() leading to deadlock. netvsc_netdev_event() netvsc_vf_setxdp() dev_xdp_propagate() This deadlock was not observed so far because net_shaper_ops was never set, and thus the lock was effectively a no-op in this case. Fix this by using netif_xdp_propagate() instead of dev_xdp_propagate() to avoid recursive locking in this path. And, since no deadlock is observed on the other path which is via netvsc_probe, add the lock exclusivly for that path. Also, clean up the unregistration path by removing the unnecessary call to netvsc_vf_setxdp(), since unregister_netdevice_many_notify() already performs this cleanup via dev_xdp_uninstall(). Fixes: 97246d6d21c2 ("net: hold netdev instance lock during ndo_bpf") Cc: stable@vger.kernel.org Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com> Tested-by: Erni Sri Satya Vennela <ernis@linux.microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Reviewed-by: Subbaraya Sundeep <sbhatta@marvell.com> Link: https://patch.msgid.link/1748513910-23963-1-git-send-email-ssengar@linux.microsoft.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
The MANA driver's probe registers netdevice via the following call chain:

mana_probe()
  register_netdev()
    register_netdevice()

register_netdevice() calls notifier callback for netvsc driver,
holding the netdev mutex via netdev_lock_ops().

Further this netvsc notifier callback end up attempting to acquire the
same lock again in dev_xdp_propagate() leading to deadlock.

netvsc_netdev_event()
  netvsc_vf_setxdp()
    dev_xdp_propagate()

This deadlock was not observed so far because net_shaper_ops was never set,
and thus the lock was effectively a no-op in this case. Fix this by using
netif_xdp_propagate() instead of dev_xdp_propagate() to avoid recursive
locking in this path.

And, since no deadlock is observed on the other path which is via
netvsc_probe, add the lock exclusivly for that path.

Also, clean up the unregistration path by removing the unnecessary call to
netvsc_vf_setxdp(), since unregister_netdevice_many_notify() already
performs this cleanup via dev_xdp_uninstall().

Fixes: 97246d6d21c2 ("net: hold netdev instance lock during ndo_bpf")
Cc: stable@vger.kernel.org
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Tested-by: Erni Sri Satya Vennela <ernis@linux.microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Subbaraya Sundeep <sbhatta@marvell.com>
Link: https://patch.msgid.link/1748513910-23963-1-git-send-email-ssengar@linux.microsoft.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: core: Convert dev_set_mac_address() to struct sockaddr_storage 2025-05-27T06:25:43+00:00 Kees Cook kees@kernel.org 2025-05-21T20:46:14+00:00 9ca6804ab7c34f65fcf2e29333a39e7807c30b60 All users of dev_set_mac_address() are now using a struct sockaddr_storage. Convert the internal data type to struct sockaddr_storage, drop the casts, and update pointer types. Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org> Signed-off-by: Kees Cook <kees@kernel.org> Link: https://patch.msgid.link/20250521204619.2301870-6-kees@kernel.org Signed-off-by: Paolo Abeni <pabeni@redhat.com> 
All users of dev_set_mac_address() are now using a struct sockaddr_storage.
Convert the internal data type to struct sockaddr_storage, drop the casts,
and update pointer types.

Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20250521204619.2301870-6-kees@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
net: core: Switch netif_set_mac_address() to struct sockaddr_storage 2025-05-27T06:25:42+00:00 Kees Cook kees@kernel.org 2025-05-21T20:46:10+00:00 161972650d6795ea00f8b72557cf3c3e593ed250 In order to avoid passing around struct sockaddr that has a size the compiler cannot reason about (nor track at runtime), convert netif_set_mac_address() to take struct sockaddr_storage. This is just a cast conversion, so there is are no binary changes. Following patches will make actual allocation changes. Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org> Signed-off-by: Kees Cook <kees@kernel.org> Link: https://patch.msgid.link/20250521204619.2301870-2-kees@kernel.org Signed-off-by: Paolo Abeni <pabeni@redhat.com> 
In order to avoid passing around struct sockaddr that has a size the
compiler cannot reason about (nor track at runtime), convert
netif_set_mac_address() to take struct sockaddr_storage. This is just a
cast conversion, so there is are no binary changes. Following patches
will make actual allocation changes.

Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20250521204619.2301870-2-kees@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
net: add debug checks in ____napi_schedule() and napi_poll() 2025-05-22T03:44:11+00:00 Eric Dumazet edumazet@google.com 2025-05-20T12:19:08+00:00 945301db34f14eaa0be794458b67aead74ff79fa While tracking an IDPF bug, I found that idpf_vport_splitq_napi_poll() was not following NAPI rules. It can indeed return @budget after napi_complete() has been called. Add two debug conditions in networking core to hopefully catch this kind of bugs sooner. IDPF bug will be fixed in a separate patch. [ 72.441242] repoll requested for device eth1 idpf_vport_splitq_napi_poll [idpf] but napi is not scheduled. [ 72.446291] list_del corruption. next->prev should be ff31783d93b14040, but was ff31783d93b10080. (next=ff31783d93b10080) [ 72.446659] kernel BUG at lib/list_debug.c:67! [ 72.446816] Oops: invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC NOPTI [ 72.447031] CPU: 156 UID: 0 PID: 16258 Comm: ip Tainted: G W 6.15.0-dbg-DEV #1944 NONE [ 72.447340] Tainted: [W]=WARN [ 72.447702] RIP: 0010:__list_del_entry_valid_or_report (lib/list_debug.c:65) [ 72.450630] Call Trace: [ 72.450720] <IRQ> [ 72.450797] net_rx_action (include/linux/list.h:215 include/linux/list.h:287 net/core/dev.c:7385 net/core/dev.c:7516) [ 72.450928] ? lock_release (kernel/locking/lockdep.c:?) [ 72.451059] ? clockevents_program_event (kernel/time/clockevents.c:?) [ 72.451222] handle_softirqs (kernel/softirq.c:579) [ 72.451356] ? do_softirq (kernel/softirq.c:480) [ 72.451480] ? idpf_vc_xn_exec (drivers/net/ethernet/intel/idpf/idpf_virtchnl.c:462) idpf [ 72.451635] do_softirq (kernel/softirq.c:480) [ 72.451750] </IRQ> [ 72.451828] <TASK> [ 72.451905] __local_bh_enable_ip (kernel/softirq.c:?) [ 72.452051] idpf_vc_xn_exec (drivers/net/ethernet/intel/idpf/idpf_virtchnl.c:462) idpf [ 72.452210] idpf_send_delete_queues_msg (drivers/net/ethernet/intel/idpf/idpf_virtchnl.c:2083) idpf [ 72.452390] idpf_vport_stop (drivers/net/ethernet/intel/idpf/idpf_lib.c:837 drivers/net/ethernet/intel/idpf/idpf_lib.c:868) idpf [ 72.452541] ? idpf_vport_stop (include/linux/bottom_half.h:? include/linux/netdevice.h:4762 drivers/net/ethernet/intel/idpf/idpf_lib.c:855) idpf [ 72.452695] idpf_initiate_soft_reset (drivers/net/ethernet/intel/idpf/idpf_lib.c:?) idpf [ 72.452867] idpf_change_mtu (drivers/net/ethernet/intel/idpf/idpf_lib.c:2189) idpf [ 72.453015] netif_set_mtu_ext (net/core/dev.c:9437) [ 72.453157] ? packet_notifier (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 net/packet/af_packet.c:4240) [ 72.453292] netif_set_mtu (net/core/dev.c:9515) [ 72.453416] dev_set_mtu (net/core/dev_api.c:?) [ 72.453534] bond_change_mtu (drivers/net/bonding/bond_main.c:4833) [ 72.453666] netif_set_mtu_ext (net/core/dev.c:9437) [ 72.453803] do_setlink (net/core/rtnetlink.c:3116) [ 72.453925] ? rtnl_newlink (net/core/rtnetlink.c:3901) [ 72.454055] ? rtnl_newlink (net/core/rtnetlink.c:3901) [ 72.454185] ? rtnl_newlink (net/core/rtnetlink.c:3901) [ 72.454314] ? trace_contention_end (include/trace/events/lock.h:122) [ 72.454467] ? __mutex_lock (arch/x86/include/asm/preempt.h:85 kernel/locking/mutex.c:611 kernel/locking/mutex.c:746) [ 72.454597] ? cap_capable (include/trace/events/capability.h:26) [ 72.454721] ? security_capable (security/security.c:?) [ 72.454857] rtnl_newlink (net/core/rtnetlink.c:?) [ 72.454982] ? lock_is_held_type (kernel/locking/lockdep.c:5599 kernel/locking/lockdep.c:5938) [ 72.455121] ? __lock_acquire (kernel/locking/lockdep.c:?) [ 72.455256] ? __change_page_attr_set_clr (arch/x86/mm/pat/set_memory.c:685) [ 72.455438] ? __lock_acquire (kernel/locking/lockdep.c:?) [ 72.455582] ? rtnetlink_rcv_msg (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 net/core/rtnetlink.c:6885) [ 72.455721] ? lock_acquire (kernel/locking/lockdep.c:5866) [ 72.455848] ? rtnetlink_rcv_msg (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 net/core/rtnetlink.c:6885) [ 72.455987] ? lock_release (kernel/locking/lockdep.c:?) [ 72.456117] ? rcu_read_unlock (include/linux/rcupdate.h:341 include/linux/rcupdate.h:871) [ 72.456249] ? __pfx_rtnl_newlink (net/core/rtnetlink.c:3956) [ 72.456388] rtnetlink_rcv_msg (net/core/rtnetlink.c:6955) [ 72.456526] ? rtnetlink_rcv_msg (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 net/core/rtnetlink.c:6885) [ 72.456671] ? lock_acquire (kernel/locking/lockdep.c:5866) [ 72.456802] ? net_generic (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 include/net/netns/generic.h:45) [ 72.456929] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6858) [ 72.457082] netlink_rcv_skb (net/netlink/af_netlink.c:2534) [ 72.457212] netlink_unicast (net/netlink/af_netlink.c:1313) [ 72.457344] netlink_sendmsg (net/netlink/af_netlink.c:1883) [ 72.457476] __sock_sendmsg (net/socket.c:712) [ 72.457602] ____sys_sendmsg (net/socket.c:?) [ 72.457735] ? _copy_from_user (arch/x86/include/asm/uaccess_64.h:126 arch/x86/include/asm/uaccess_64.h:134 arch/x86/include/asm/uaccess_64.h:141 include/linux/uaccess.h:178 lib/usercopy.c:18) [ 72.457875] ___sys_sendmsg (net/socket.c:2620) [ 72.458042] ? __call_rcu_common (arch/x86/include/asm/irqflags.h:42 arch/x86/include/asm/irqflags.h:119 arch/x86/include/asm/irqflags.h:159 kernel/rcu/tree.c:3107) [ 72.458185] ? mntput_no_expire (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 fs/namespace.c:1457) [ 72.458324] ? lock_acquire (kernel/locking/lockdep.c:5866) [ 72.458451] ? mntput_no_expire (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 fs/namespace.c:1457) [ 72.458588] ? lock_release (kernel/locking/lockdep.c:?) [ 72.458718] ? mntput_no_expire (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 fs/namespace.c:1457) [ 72.458856] __x64_sys_sendmsg (net/socket.c:2652) [ 72.458997] ? do_syscall_64 (arch/x86/include/asm/irqflags.h:42 arch/x86/include/asm/irqflags.h:119 include/linux/entry-common.h:198 arch/x86/entry/syscall_64.c:90) [ 72.459136] do_syscall_64 (arch/x86/entry/syscall_64.c:?) [ 72.459259] ? exc_page_fault (arch/x86/mm/fault.c:1542) [ 72.459387] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) [ 72.459555] RIP: 0033:0x7fd15f17cbd0 Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250520121908.1805732-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
While tracking an IDPF bug, I found that idpf_vport_splitq_napi_poll()
was not following NAPI rules.

It can indeed return @budget after napi_complete() has been called.

Add two debug conditions in networking core to hopefully catch
this kind of bugs sooner.

IDPF bug will be fixed in a separate patch.

[   72.441242] repoll requested for device eth1 idpf_vport_splitq_napi_poll [idpf] but napi is not scheduled.
[   72.446291] list_del corruption. next->prev should be ff31783d93b14040, but was ff31783d93b10080. (next=ff31783d93b10080)
[   72.446659] kernel BUG at lib/list_debug.c:67!
[   72.446816] Oops: invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC NOPTI
[   72.447031] CPU: 156 UID: 0 PID: 16258 Comm: ip Tainted: G        W           6.15.0-dbg-DEV #1944 NONE
[   72.447340] Tainted: [W]=WARN
[   72.447702] RIP: 0010:__list_del_entry_valid_or_report (lib/list_debug.c:65)
[   72.450630] Call Trace:
[   72.450720]  <IRQ>
[   72.450797] net_rx_action (include/linux/list.h:215 include/linux/list.h:287 net/core/dev.c:7385 net/core/dev.c:7516)
[   72.450928] ? lock_release (kernel/locking/lockdep.c:?)
[   72.451059] ? clockevents_program_event (kernel/time/clockevents.c:?)
[   72.451222] handle_softirqs (kernel/softirq.c:579)
[   72.451356] ? do_softirq (kernel/softirq.c:480)
[   72.451480] ? idpf_vc_xn_exec (drivers/net/ethernet/intel/idpf/idpf_virtchnl.c:462) idpf
[   72.451635] do_softirq (kernel/softirq.c:480)
[   72.451750]  </IRQ>
[   72.451828]  <TASK>
[   72.451905] __local_bh_enable_ip (kernel/softirq.c:?)
[   72.452051] idpf_vc_xn_exec (drivers/net/ethernet/intel/idpf/idpf_virtchnl.c:462) idpf
[   72.452210] idpf_send_delete_queues_msg (drivers/net/ethernet/intel/idpf/idpf_virtchnl.c:2083) idpf
[   72.452390] idpf_vport_stop (drivers/net/ethernet/intel/idpf/idpf_lib.c:837 drivers/net/ethernet/intel/idpf/idpf_lib.c:868) idpf
[   72.452541] ? idpf_vport_stop (include/linux/bottom_half.h:? include/linux/netdevice.h:4762 drivers/net/ethernet/intel/idpf/idpf_lib.c:855) idpf
[   72.452695] idpf_initiate_soft_reset (drivers/net/ethernet/intel/idpf/idpf_lib.c:?) idpf
[   72.452867] idpf_change_mtu (drivers/net/ethernet/intel/idpf/idpf_lib.c:2189) idpf
[   72.453015] netif_set_mtu_ext (net/core/dev.c:9437)
[   72.453157] ? packet_notifier (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 net/packet/af_packet.c:4240)
[   72.453292] netif_set_mtu (net/core/dev.c:9515)
[   72.453416] dev_set_mtu (net/core/dev_api.c:?)
[   72.453534] bond_change_mtu (drivers/net/bonding/bond_main.c:4833)
[   72.453666] netif_set_mtu_ext (net/core/dev.c:9437)
[   72.453803] do_setlink (net/core/rtnetlink.c:3116)
[   72.453925] ? rtnl_newlink (net/core/rtnetlink.c:3901)
[   72.454055] ? rtnl_newlink (net/core/rtnetlink.c:3901)
[   72.454185] ? rtnl_newlink (net/core/rtnetlink.c:3901)
[   72.454314] ? trace_contention_end (include/trace/events/lock.h:122)
[   72.454467] ? __mutex_lock (arch/x86/include/asm/preempt.h:85 kernel/locking/mutex.c:611 kernel/locking/mutex.c:746)
[   72.454597] ? cap_capable (include/trace/events/capability.h:26)
[   72.454721] ? security_capable (security/security.c:?)
[   72.454857] rtnl_newlink (net/core/rtnetlink.c:?)
[   72.454982] ? lock_is_held_type (kernel/locking/lockdep.c:5599 kernel/locking/lockdep.c:5938)
[   72.455121] ? __lock_acquire (kernel/locking/lockdep.c:?)
[   72.455256] ? __change_page_attr_set_clr (arch/x86/mm/pat/set_memory.c:685)
[   72.455438] ? __lock_acquire (kernel/locking/lockdep.c:?)
[   72.455582] ? rtnetlink_rcv_msg (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 net/core/rtnetlink.c:6885)
[   72.455721] ? lock_acquire (kernel/locking/lockdep.c:5866)
[   72.455848] ? rtnetlink_rcv_msg (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 net/core/rtnetlink.c:6885)
[   72.455987] ? lock_release (kernel/locking/lockdep.c:?)
[   72.456117] ? rcu_read_unlock (include/linux/rcupdate.h:341 include/linux/rcupdate.h:871)
[   72.456249] ? __pfx_rtnl_newlink (net/core/rtnetlink.c:3956)
[   72.456388] rtnetlink_rcv_msg (net/core/rtnetlink.c:6955)
[   72.456526] ? rtnetlink_rcv_msg (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 net/core/rtnetlink.c:6885)
[   72.456671] ? lock_acquire (kernel/locking/lockdep.c:5866)
[   72.456802] ? net_generic (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 include/net/netns/generic.h:45)
[   72.456929] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6858)
[   72.457082] netlink_rcv_skb (net/netlink/af_netlink.c:2534)
[   72.457212] netlink_unicast (net/netlink/af_netlink.c:1313)
[   72.457344] netlink_sendmsg (net/netlink/af_netlink.c:1883)
[   72.457476] __sock_sendmsg (net/socket.c:712)
[   72.457602] ____sys_sendmsg (net/socket.c:?)
[   72.457735] ? _copy_from_user (arch/x86/include/asm/uaccess_64.h:126 arch/x86/include/asm/uaccess_64.h:134 arch/x86/include/asm/uaccess_64.h:141 include/linux/uaccess.h:178 lib/usercopy.c:18)
[   72.457875] ___sys_sendmsg (net/socket.c:2620)
[   72.458042] ? __call_rcu_common (arch/x86/include/asm/irqflags.h:42 arch/x86/include/asm/irqflags.h:119 arch/x86/include/asm/irqflags.h:159 kernel/rcu/tree.c:3107)
[   72.458185] ? mntput_no_expire (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 fs/namespace.c:1457)
[   72.458324] ? lock_acquire (kernel/locking/lockdep.c:5866)
[   72.458451] ? mntput_no_expire (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 fs/namespace.c:1457)
[   72.458588] ? lock_release (kernel/locking/lockdep.c:?)
[   72.458718] ? mntput_no_expire (include/linux/rcupdate.h:331 include/linux/rcupdate.h:841 fs/namespace.c:1457)
[   72.458856] __x64_sys_sendmsg (net/socket.c:2652)
[   72.458997] ? do_syscall_64 (arch/x86/include/asm/irqflags.h:42 arch/x86/include/asm/irqflags.h:119 include/linux/entry-common.h:198 arch/x86/entry/syscall_64.c:90)
[   72.459136] do_syscall_64 (arch/x86/entry/syscall_64.c:?)
[   72.459259] ? exc_page_fault (arch/x86/mm/fault.c:1542)
[   72.459387] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   72.459555] RIP: 0033:0x7fd15f17cbd0

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250520121908.1805732-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: use skb_crc32c() in skb_crc32c_csum_help() 2025-05-21T22:39:59+00:00 Eric Biggers ebiggers@google.com 2025-05-19T17:50:05+00:00 86edc94da1063a327d8d4bfc82b31df427db3e5c Instead of calling __skb_checksum() with a skb_checksum_ops struct that does CRC32C, just call the new function skb_crc32c(). This is faster and simpler. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://patch.msgid.link/20250519175012.36581-4-ebiggers@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Instead of calling __skb_checksum() with a skb_checksum_ops struct that
does CRC32C, just call the new function skb_crc32c().  This is faster
and simpler.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://patch.msgid.link/20250519175012.36581-4-ebiggers@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: introduce CONFIG_NET_CRC32C 2025-05-21T22:39:58+00:00 Eric Biggers ebiggers@google.com 2025-05-19T17:50:03+00:00 55d22ee0358597185f8f5272558ec7cf1a49eb41 Add a hidden kconfig symbol NET_CRC32C that will group together the functions that calculate CRC32C checksums of packets, so that these don't have to be built into NET-enabled kernels that don't need them. Make skb_crc32c_csum_help() (which is called only when IP_SCTP is enabled) conditional on this symbol, and make IP_SCTP select it. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://patch.msgid.link/20250519175012.36581-2-ebiggers@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Add a hidden kconfig symbol NET_CRC32C that will group together the
functions that calculate CRC32C checksums of packets, so that these
don't have to be built into NET-enabled kernels that don't need them.

Make skb_crc32c_csum_help() (which is called only when IP_SCTP is
enabled) conditional on this symbol, and make IP_SCTP select it.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://patch.msgid.link/20250519175012.36581-2-ebiggers@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
selftests: net: validate team flags propagation 2025-05-21T01:12:58+00:00 Stanislav Fomichev stfomichev@gmail.com 2025-05-16T23:22:05+00:00 f792709e0baad67224180d73d51c2f090003adde Cover three recent cases: 1. missing ops locking for the lowers during netdev_sync_lower_features 2. missing locking for dev_set_promiscuity (plus netdev_ops_assert_locked with a comment on why/when it's needed) 3. rcu lock during team_change_rx_flags Verified that each one triggers when the respective fix is reverted. Not sure about the placement, but since it all relies on teaming, added to the teaming directory. One ugly bit is that I add NETIF_F_LRO to netdevsim; there is no way to trigger netdev_sync_lower_features without it. Signed-off-by: Stanislav Fomichev <stfomichev@gmail.com> Link: https://patch.msgid.link/20250516232205.539266-1-stfomichev@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Cover three recent cases:
1. missing ops locking for the lowers during netdev_sync_lower_features
2. missing locking for dev_set_promiscuity (plus netdev_ops_assert_locked
   with a comment on why/when it's needed)
3. rcu lock during team_change_rx_flags

Verified that each one triggers when the respective fix is reverted.
Not sure about the placement, but since it all relies on teaming,
added to the teaming directory.

One ugly bit is that I add NETIF_F_LRO to netdevsim; there is no way
to trigger netdev_sync_lower_features without it.

Signed-off-by: Stanislav Fomichev <stfomichev@gmail.com>
Link: https://patch.msgid.link/20250516232205.539266-1-stfomichev@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-05-15T18:28:30+00:00 Jakub Kicinski kuba@kernel.org 2025-05-15T18:22:32+00:00 bebd7b262638af611a0e699ba37c43ec2238801b Cross-merge networking fixes after downstream PR (net-6.15-rc7). Conflicts: tools/testing/selftests/drivers/net/hw/ncdevmem.c 97c4e094a4b2 ("tests/ncdevmem: Fix double-free of queue array") 2f1a805f32ba ("selftests: ncdevmem: Implement devmem TCP TX") https://lore.kernel.org/20250514122900.1e77d62d@canb.auug.org.au Adjacent changes: net/core/devmem.c net/core/devmem.h 0afc44d8cdf6 ("net: devmem: fix kernel panic when netlink socket close after module unload") bd61848900bf ("net: devmem: Implement TX path") Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Cross-merge networking fixes after downstream PR (net-6.15-rc7).

Conflicts:

tools/testing/selftests/drivers/net/hw/ncdevmem.c
  97c4e094a4b2 ("tests/ncdevmem: Fix double-free of queue array")
  2f1a805f32ba ("selftests: ncdevmem: Implement devmem TCP TX")
https://lore.kernel.org/20250514122900.1e77d62d@canb.auug.org.au

Adjacent changes:

net/core/devmem.c
net/core/devmem.h
  0afc44d8cdf6 ("net: devmem: fix kernel panic when netlink socket close after module unload")
  bd61848900bf ("net: devmem: Implement TX path")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>