A DSA master interface has upper network devices, each representing an
Ethernet switch port attached to it. Demultiplexing the source ports and
setting skb->dev accordingly is done through the catch-all ETH_P_XDSA
packet_type handler. Catch-all because DSA vendors have various header
implementations, which can be placed anywhere in the frame: before the
DMAC, before the EtherType, before the FCS, etc. So, the ETH_P_XDSA
handler acts like an rx_handler more than anything.

It is unlikely for the DSA master interface to have any other upper than
the DSA switch interfaces themselves. Only maybe a bridge upper*, but it
is very likely that the DSA master will have no 8021q upper. So
__netif_receive_skb_core() will try to untag the VLAN, despite the fact
that the DSA switch interface might have an 8021q upper. So the skb will
never reach that.

So far, this hasn't been a problem because most of the possible
placements of the DSA switch header mentioned in the first paragraph
will displace the VLAN header when the DSA master receives the frame, so
__netif_receive_skb_core() will not actually execute any VLAN-specific
code for it. This only becomes a problem when the DSA switch header does
not displace the VLAN header (for example with a tail tag).

What the patch does is it bypasses the untagging of the skb when there
is a DSA switch attached to this net device. So, DSA is the only
packet_type handler which requires seeing the VLAN header. Once skb->dev
will be changed, __netif_receive_skb_core() will be invoked again and
untagging, or delivery to an 8021q upper, will happen in the RX of the
DSA switch interface itself.

*see commit 9eb8eff0 ("net: bridge: allow enslaving some DSA master
network devices". This is actually the reason why I prefer keeping DSA
as a packet_type handler of ETH_P_XDSA rather than converting to an
rx_handler. Currently the rx_handler code doesn't support chaining, and
this is a problem because a DSA master might be bridged.
Signed-off-by: NVladimir Oltean <olteanv@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

flush_all_backlogs() may cause deadlock on systems
running processes with FIFO scheduling policy.

The above is critical in -RT scenarios, where user-space
specifically ensure no network activity is scheduled on
the CPU running the mentioned FIFO process, but still get
stuck.

This commit tries to address the problem checking the
backlog status on the remote CPUs before scheduling the
flush operation. If the backlog is empty, we can skip it.

v1 -> v2:
 - explicitly clear flushed cpu mask - Eric
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

netpoll needs to traverse dev->napi_list under RCU, make
sure it uses the right iterator and that removal from this
list is handled safely.
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

To RCUify napi->dev_list we need to replace list_del_init()
with list_del_rcu(). There is no _init() version for RCU for
obvious reasons. Up until now netif_napi_del() was idempotent
so to make sure it remains such add a bit which is set when
NAPI is listed, and cleared when it removed. Since we don't
expect multiple calls to netif_napi_add() to be correct,
add a warning on that side.

Now that napi_hash_add / napi_hash_del are only called by
napi_add / del we can actually steal its bit. We just need
to make sure hash node is initialized correctly.
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We allow drivers to call napi_hash_del() before calling
netif_napi_del() to batch RCU grace periods. This makes
the API asymmetric and leaks internal implementation details.
Soon we will want the grace period to protect more than just
the NAPI hash table.

Restructure the API and have drivers call a new function -
__netif_napi_del() if they want to take care of RCU waits.

Note that only core was checking the return status from
napi_hash_del() so the new helper does not report if the
NAPI was actually deleted.

Some notes on driver oddness:
 - veth observed the grace period before calling netif_napi_del()
   but that should not matter
 - myri10ge observed normal RCU flavor
 - bnx2x and enic did not actually observe the grace period
   (unless they did so implicitly)
 - virtio_net and enic only unhashed Rx NAPIs

The last two points seem to indicate that the calls to
napi_hash_del() were a left over rather than an optimization.
Regardless, it's easy enough to correct them.

This patch may introduce extra synchronize_net() calls for
interfaces which set NAPI_STATE_NO_BUSY_POLL and depend on
free_netdev() to call netif_napi_del(). This seems inevitable
since we want to use RCU for netpoll dev->napi_list traversal,
and almost no drivers set IFF_DISABLE_NETPOLL.
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NJonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

napi_disable() makes sure to set the NAPI_STATE_NPSVC bit to prevent
netpoll from accessing rings before init is complete. However, the
same is not done for fresh napi instances in netif_napi_add(),
even though we expect NAPI instances to be added as disabled.

This causes crashes during driver reconfiguration (enabling XDP,
changing the channel count) - if there is any printk() after
netif_napi_add() but before napi_enable().

To ensure memory ordering is correct we need to use RCU accessors.
Reported-by: NRob Sherwood <rsher@fb.com>
Fixes: 2d8bff12 ("netpoll: Close race condition between poll_one_napi and napi_disable")
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-throughSigned-off-by: NGustavo A. R. Silva <gustavoars@kernel.org>

7f0a8382 ("bpf, xdp: Maintain info on attached XDP BPF programs in net_device")
inadvertently changed which XDP mode is assumed when no mode flags are
specified explicitly. Previously, driver mode was preferred, if driver
supported it. If not, generic SKB mode was chosen. That commit changed default
to SKB mode always. This patch fixes the issue and restores the original
logic.

Fixes: 7f0a8382 ("bpf, xdp: Maintain info on attached XDP BPF programs in net_device")
Reported-by: NLorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Tested-by: NLorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/bpf/20200820052841.1559757-1-andriin@fb.com

This reverts commit f8414a8d.

eth_type_trans() does the necessary pull on the skb.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When an XDP program changes the ethernet header protocol field,
eth_type_trans is used to recalculate skb->protocol. In order for
eth_type_trans to work correctly, the ethernet header must actually be
part of the skb data segment, so the code first pushes that onto the
head of the skb. However, it subsequently forgets to pull it back off,
making the behavior of the passed-on packet inconsistent between the
protocol modifying case and the static protocol case. This patch fixes
the issue by simply pulling the ethernet header back off of the skb
head.

Fixes: 29724956 ("net: fix generic XDP to handle if eth header was mangled")
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Enforce XDP_FLAGS_UPDATE_IF_NOEXIST only if new BPF program to be attached is
non-NULL (i.e., we are not detaching a BPF program).

Fixes: d4baa936 ("bpf, xdp: Extract common XDP program attachment logic")
Reported-by: NStanislav Fomichev <sdf@google.com>
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Tested-by: NStanislav Fomichev <sdf@google.com>
Acked-by: NToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20200812022923.1217922-1-andriin@fb.com

Add LINK_DETACH command to force-detach bpf_link without destroying it. It has
the same behavior as auto-detaching of bpf_link due to cgroup dying for
bpf_cgroup_link or net_device being destroyed for bpf_xdp_link. In such case,
bpf_link is still a valid kernel object, but is defuncts and doesn't hold BPF
program attached to corresponding BPF hook. This functionality allows users
with enough access rights to manually force-detach attached bpf_link without
killing respective owner process.

This patch implements LINK_DETACH for cgroup, xdp, and netns links, mostly
re-using existing link release handling code.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NSong Liu <songliubraving@fb.com>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200731182830.286260-2-andriin@fb.com

netdev protodown is a mechanism that allows protocols to
hold an interface down. It was initially introduced in
the kernel to hold links down by a multihoming protocol.
There was also an attempt to introduce protodown
reason at the time but was rejected. protodown and protodown reason
is supported by almost every switching and routing platform.
It was ok for a while to live without a protodown reason.
But, its become more critical now given more than
one protocol may need to keep a link down on a system
at the same time. eg: vrrp peer node, port security,
multihoming protocol. Its common for Network operators and
protocol developers to look for such a reason on a networking
box (Its also known as errDisable by most networking operators)

This patch adds support for link protodown reason
attribute. There are two ways to maintain protodown
reasons.
(a) enumerate every possible reason code in kernel
    - A protocol developer has to make a request and
      have that appear in a certain kernel version
(b) provide the bits in the kernel, and allow user-space
(sysadmin or NOS distributions) to manage the bit-to-reasonname
map.
	- This makes extending reason codes easier (kind of like
      the iproute2 table to vrf-name map /etc/iproute2/rt_tables.d/)

This patch takes approach (b).

a few things about the patch:
- It treats the protodown reason bits as counter to indicate
active protodown users
- Since protodown attribute is already an exposed UAPI,
the reason is not enforced on a protodown set. Its a no-op
if not used.
the patch follows the below algorithm:
  - presence of reason bits set indicates protodown
    is in use
  - user can set protodown and protodown reason in a
    single or multiple setlink operations
  - setlink operation to clear protodown, will return -EBUSY
    if there are active protodown reason bits
  - reason is not included in link dumps if not used

example with patched iproute2:
$cat /etc/iproute2/protodown_reasons.d/r.conf
0 mlag
1 evpn
2 vrrp
3 psecurity

$ip link set dev vxlan0 protodown on protodown_reason vrrp on
$ip link set dev vxlan0 protodown_reason mlag on
$ip link show
14: vxlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode
DEFAULT group default qlen 1000
    link/ether f6:06:be:17:91:e7 brd ff:ff:ff:ff:ff:ff protodown on <mlag,vrrp>

$ip link set dev vxlan0 protodown_reason mlag off
$ip link set dev vxlan0 protodown off protodown_reason vrrp off
Signed-off-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When we don't care about vlan depth, we could pass NULL instead of the
address of a unused local variable to skb_network_protocol() as a param.
Signed-off-by: NMiaohe Lin <linmiaohe@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that BPF program/link management is centralized in generic net_device
code, kernel code never queries program id from drivers, so
XDP_QUERY_PROG/XDP_QUERY_PROG_HW commands are unnecessary.

This patch removes all the implementations of those commands in kernel, along
the xdp_attachment_query().

This patch was compile-tested on allyesconfig.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200722064603.3350758-10-andriin@fb.com

Implement XDP link-specific show_fdinfo and link_info to emit ifindex.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200722064603.3350758-7-andriin@fb.com

Add support for LINK_UPDATE command for BPF XDP link to enable reliable
replacement of underlying BPF program.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200722064603.3350758-6-andriin@fb.com

Add bpf_link-based API (bpf_xdp_link) to attach BPF XDP program through
BPF_LINK_CREATE command.

bpf_xdp_link is mutually exclusive with direct BPF program attachment,
previous BPF program should be detached prior to attempting to create a new
bpf_xdp_link attachment (for a given XDP mode). Once BPF link is attached, it
can't be replaced by other BPF program attachment or link attachment. It will
be detached only when the last BPF link FD is closed.

bpf_xdp_link will be auto-detached when net_device is shutdown, similarly to
how other BPF links behave (cgroup, flow_dissector). At that point bpf_link
will become defunct, but won't be destroyed until last FD is closed.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200722064603.3350758-5-andriin@fb.com

Further refactor XDP attachment code. dev_change_xdp_fd() is split into two
parts: getting bpf_progs from FDs and attachment logic, working with
bpf_progs. This makes attachment  logic a bit more straightforward and
prepares code for bpf_xdp_link inclusion, which will share the common logic.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200722064603.3350758-4-andriin@fb.com

Instead of delegating to drivers, maintain information about which BPF
programs are attached in which XDP modes (generic/skb, driver, or hardware)
locally in net_device. This effectively obsoletes XDP_QUERY_PROG command.

Such re-organization simplifies existing code already. But it also allows to
further add bpf_link-based XDP attachments without drivers having to know
about any of this at all, which seems like a good setup.
XDP_SETUP_PROG/XDP_SETUP_PROG_HW are just low-level commands to driver to
install/uninstall active BPF program. All the higher-level concerns about
prog/link interaction will be contained within generic driver-agnostic logic.

All the XDP_QUERY_PROG calls to driver in dev_xdp_uninstall() were removed.
It's not clear for me why dev_xdp_uninstall() were passing previous prog_flags
when resetting installed programs. That seems unnecessary, plus most drivers
don't populate prog_flags anyways. Having XDP_SETUP_PROG vs XDP_SETUP_PROG_HW
should be enough of an indicator of what is required of driver to correctly
reset active BPF program. dev_xdp_uninstall() is also generalized as an
iteration over all three supported mode.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200722064603.3350758-3-andriin@fb.com

IRQs are disabled when freeing skbs in input queue.
Use the IRQ safe variant to free skbs here.

Fixes: 145dd5f9 ("net: flush the softnet backlog in process context")
Signed-off-by: NSubash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The purpose of this override is to give the user an indication of what
the number of the CPU port is (in DSA, the CPU port is a hardware
implementation detail and not a network interface capable of traffic).

However, it has always failed (by design) at providing this information
to the user in a reliable fashion.

Prior to commit 3369afba ("net: Call into DSA netdevice_ops
wrappers"), the behavior was to only override this callback if it was
not provided by the DSA master.

That was its first failure: if the DSA master itself was a DSA port or a
switchdev, then the user would not see the number of the CPU port in
/sys/class/net/eth0/phys_port_name, but the number of the DSA master
port within its respective physical switch.

But that was actually ok in a way. The commit mentioned above changed
that behavior, and now overrides the master's ndo_get_phys_port_name
unconditionally. That comes with problems of its own, which are worse in
a way.

The idea is that it's typical for switchdev users to have udev rules for
consistent interface naming. These are based, among other things, on
the phys_port_name attribute. If we let the DSA switch at the bottom
to start randomly overriding ndo_get_phys_port_name with its own CPU
port, we basically lose any predictability in interface naming, or even
uniqueness, for that matter.

So, there are reasons to let DSA override the master's callback (to
provide a consistent interface, a number which has a clear meaning and
must not be interpreted according to context), and there are reasons to
not let DSA override it (it breaks udev matching for the DSA master).

But, there is an alternative method for users to retrieve the number of
the CPU port of each DSA switch in the system:

  $ devlink port
  pci/0000:00:00.5/0: type eth netdev swp0 flavour physical port 0
  pci/0000:00:00.5/2: type eth netdev swp2 flavour physical port 2
  pci/0000:00:00.5/4: type notset flavour cpu port 4
  spi/spi2.0/0: type eth netdev sw0p0 flavour physical port 0
  spi/spi2.0/1: type eth netdev sw0p1 flavour physical port 1
  spi/spi2.0/2: type eth netdev sw0p2 flavour physical port 2
  spi/spi2.0/4: type notset flavour cpu port 4
  spi/spi2.1/0: type eth netdev sw1p0 flavour physical port 0
  spi/spi2.1/1: type eth netdev sw1p1 flavour physical port 1
  spi/spi2.1/2: type eth netdev sw1p2 flavour physical port 2
  spi/spi2.1/3: type eth netdev sw1p3 flavour physical port 3
  spi/spi2.1/4: type notset flavour cpu port 4

So remove this duplicated, unreliable and troublesome method. From this
patch on, the phys_port_name attribute of the DSA master will only
contain information about itself (if at all). If the users need reliable
information about the CPU port they're probably using devlink anyway.
Signed-off-by: NVladimir Oltean <olteanv@gmail.com>
Acked-by: Nflorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Make the core net_device code call into our ndo_do_ioctl() and
ndo_get_phys_port_name() functions via the wrappers defined previously
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit aebe4426.
Signed-off-by: NPetr Machata <petrm@mellanox.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Introduce the capability to attach an eBPF program to cpumap entries.
The idea behind this feature is to add the possibility to define on
which CPU run the eBPF program if the underlying hw does not support
RSS. Current supported verdicts are XDP_DROP and XDP_PASS.

This patch has been tested on Marvell ESPRESSObin using xdp_redirect_cpu
sample available in the kernel tree to identify possible performance
regressions. Results show there are no observable differences in
packet-per-second:

$./xdp_redirect_cpu --progname xdp_cpu_map0 --dev eth0 --cpu 1
rx: 354.8 Kpps
rx: 356.0 Kpps
rx: 356.8 Kpps
rx: 356.3 Kpps
rx: 356.6 Kpps
rx: 356.6 Kpps
rx: 356.7 Kpps
rx: 355.8 Kpps
rx: 356.8 Kpps
rx: 356.8 Kpps
Co-developed-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NLorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/5c9febdf903d810b3415732e5cd98491d7d9067a.1594734381.git.lorenzo@kernel.org

The sparse tool complains as follows:

net/core/dev.c:5594:1: warning:
 symbol '__pcpu_scope_flush_works' was not declared. Should it be static?

'flush_works' is not used outside of dev.c, so marks
it static.

Fixes: 41852497 ("net: batch calls to flush_all_backlogs()")
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Simple fixes which require no deep knowledge of the code.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A following patch introduces qevents, points in qdisc algorithm where
packet can be processed by user-defined filters. Should this processing
lead to a situation where a new packet is to be enqueued on the same port,
holding the root lock would lead to deadlocks. To solve the issue, qevent
handler needs to unlock and relock the root lock when necessary.

To that end, add the root lock argument to the qdisc op enqueue, and
propagate throughout.
Signed-off-by: NPetr Machata <petrm@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The dev argument was not listed at kernel-doc markup:

	./net/core/dev.c:7878: warning: Function parameter or member 'dev' not described in 'netdev_get_xmit_slave'
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/6e22325bb9bd4cc2249c3768b0e3ad75933445f8.1592895969.git.mchehab+huawei@kernel.orgSigned-off-by: NJonathan Corbet <corbet@lwn.net>

A netdevice may be marked as detached because the parent is
runtime-suspended and not accessible whilst interface or link is down.
An example are PCI network devices that go into PCI D3hot, see e.g.
__igc_shutdown() or rtl8169_net_suspend().
If netdevice is down and marked as detached we can only open it if
we runtime-resume it before __dev_open() calls netif_device_present().

Therefore, if netdevice is detached, try to runtime-resume the parent
and only return with an error if it's still detached.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Back in commit f60e5990 ("ipv6: protect skb->sk accesses
from recursive dereference inside the stack") Hannes added code
so that IPv6 stack would not trust skb->sk for typical cases
where packet goes through 'standard' xmit path (__dev_queue_xmit())

Alas af_packet had a dev_direct_xmit() path that was not
dealing yet with xmit_recursion level.

Also change sk_mc_loop() to dump a stack once only.

Without this patch, syzbot was able to trigger :

[1]
[  153.567378] WARNING: CPU: 7 PID: 11273 at net/core/sock.c:721 sk_mc_loop+0x51/0x70
[  153.567378] Modules linked in: nfnetlink ip6table_raw ip6table_filter iptable_raw iptable_nat nf_nat nf_conntrack nf_defrag_ipv4 nf_defrag_ipv6 iptable_filter macsec macvtap tap macvlan 8021q hsr wireguard libblake2s blake2s_x86_64 libblake2s_generic udp_tunnel ip6_udp_tunnel libchacha20poly1305 poly1305_x86_64 chacha_x86_64 libchacha curve25519_x86_64 libcurve25519_generic netdevsim batman_adv dummy team bridge stp llc w1_therm wire i2c_mux_pca954x i2c_mux cdc_acm ehci_pci ehci_hcd mlx4_en mlx4_ib ib_uverbs ib_core mlx4_core
[  153.567386] CPU: 7 PID: 11273 Comm: b159172088 Not tainted 5.8.0-smp-DEV #273
[  153.567387] RIP: 0010:sk_mc_loop+0x51/0x70
[  153.567388] Code: 66 83 f8 0a 75 24 0f b6 4f 12 b8 01 00 00 00 31 d2 d3 e0 a9 bf ef ff ff 74 07 48 8b 97 f0 02 00 00 0f b6 42 3a 83 e0 01 5d c3 <0f> 0b b8 01 00 00 00 5d c3 0f b6 87 18 03 00 00 5d c0 e8 04 83 e0
[  153.567388] RSP: 0018:ffff95c69bb93990 EFLAGS: 00010212
[  153.567388] RAX: 0000000000000011 RBX: ffff95c6e0ee3e00 RCX: 0000000000000007
[  153.567389] RDX: ffff95c69ae50000 RSI: ffff95c6c30c3000 RDI: ffff95c6c30c3000
[  153.567389] RBP: ffff95c69bb93990 R08: ffff95c69a77f000 R09: 0000000000000008
[  153.567389] R10: 0000000000000040 R11: 00003e0e00026128 R12: ffff95c6c30c3000
[  153.567390] R13: ffff95c6cc4fd500 R14: ffff95c6f84500c0 R15: ffff95c69aa13c00
[  153.567390] FS:  00007fdc3a283700(0000) GS:ffff95c6ff9c0000(0000) knlGS:0000000000000000
[  153.567390] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  153.567391] CR2: 00007ffee758e890 CR3: 0000001f9ba20003 CR4: 00000000001606e0
[  153.567391] Call Trace:
[  153.567391]  ip6_finish_output2+0x34e/0x550
[  153.567391]  __ip6_finish_output+0xe7/0x110
[  153.567391]  ip6_finish_output+0x2d/0xb0
[  153.567392]  ip6_output+0x77/0x120
[  153.567392]  ? __ip6_finish_output+0x110/0x110
[  153.567392]  ip6_local_out+0x3d/0x50
[  153.567392]  ipvlan_queue_xmit+0x56c/0x5e0
[  153.567393]  ? ksize+0x19/0x30
[  153.567393]  ipvlan_start_xmit+0x18/0x50
[  153.567393]  dev_direct_xmit+0xf3/0x1c0
[  153.567393]  packet_direct_xmit+0x69/0xa0
[  153.567394]  packet_sendmsg+0xbf0/0x19b0
[  153.567394]  ? plist_del+0x62/0xb0
[  153.567394]  sock_sendmsg+0x65/0x70
[  153.567394]  sock_write_iter+0x93/0xf0
[  153.567394]  new_sync_write+0x18e/0x1a0
[  153.567395]  __vfs_write+0x29/0x40
[  153.567395]  vfs_write+0xb9/0x1b0
[  153.567395]  ksys_write+0xb1/0xe0
[  153.567395]  __x64_sys_write+0x1a/0x20
[  153.567395]  do_syscall_64+0x43/0x70
[  153.567396]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  153.567396] RIP: 0033:0x453549
[  153.567396] Code: Bad RIP value.
[  153.567396] RSP: 002b:00007fdc3a282cc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[  153.567397] RAX: ffffffffffffffda RBX: 00000000004d32d0 RCX: 0000000000453549
[  153.567397] RDX: 0000000000000020 RSI: 0000000020000300 RDI: 0000000000000003
[  153.567398] RBP: 00000000004d32d8 R08: 0000000000000000 R09: 0000000000000000
[  153.567398] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004d32dc
[  153.567398] R13: 00007ffee742260f R14: 00007fdc3a282dc0 R15: 00007fdc3a283700
[  153.567399] ---[ end trace c1d5ae2b1059ec62 ]---

f60e5990 ("ipv6: protect skb->sk accesses from recursive dereference inside the stack")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Whenever a buggy NAPI driver returns more than its budget,
we emit a stack trace that is of no use, since it does not
tell which driver is buggy.

Instead, emit a message giving the function name, and a
descriptive message.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I got a memleak report when doing some fuzz test:

unreferenced object 0xffff888112584000 (size 13599):
  comm "ip", pid 3048, jiffies 4294911734 (age 343.491s)
  hex dump (first 32 bytes):
    74 61 70 30 00 00 00 00 00 00 00 00 00 00 00 00  tap0............
    00 ee d9 19 81 88 ff ff 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<000000002f60ba65>] __kmalloc_node+0x309/0x3a0
    [<0000000075b211ec>] kvmalloc_node+0x7f/0xc0
    [<00000000d3a97396>] alloc_netdev_mqs+0x76/0xfc0
    [<00000000609c3655>] __tun_chr_ioctl+0x1456/0x3d70
    [<000000001127ca24>] ksys_ioctl+0xe5/0x130
    [<00000000b7d5e66a>] __x64_sys_ioctl+0x6f/0xb0
    [<00000000e1023498>] do_syscall_64+0x56/0xa0
    [<000000009ec0eb12>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
unreferenced object 0xffff888111845cc0 (size 8):
  comm "ip", pid 3048, jiffies 4294911734 (age 343.491s)
  hex dump (first 8 bytes):
    74 61 70 30 00 88 ff ff                          tap0....
  backtrace:
    [<000000004c159777>] kstrdup+0x35/0x70
    [<00000000d8b496ad>] kstrdup_const+0x3d/0x50
    [<00000000494e884a>] kvasprintf_const+0xf1/0x180
    [<0000000097880a2b>] kobject_set_name_vargs+0x56/0x140
    [<000000008fbdfc7b>] dev_set_name+0xab/0xe0
    [<000000005b99e3b4>] netdev_register_kobject+0xc0/0x390
    [<00000000602704fe>] register_netdevice+0xb61/0x1250
    [<000000002b7ca244>] __tun_chr_ioctl+0x1cd1/0x3d70
    [<000000001127ca24>] ksys_ioctl+0xe5/0x130
    [<00000000b7d5e66a>] __x64_sys_ioctl+0x6f/0xb0
    [<00000000e1023498>] do_syscall_64+0x56/0xa0
    [<000000009ec0eb12>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
unreferenced object 0xffff88811886d800 (size 512):
  comm "ip", pid 3048, jiffies 4294911734 (age 343.491s)
  hex dump (first 32 bytes):
    00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00  .....N..........
    ff ff ff ff ff ff ff ff c0 66 3d a3 ff ff ff ff  .........f=.....
  backtrace:
    [<0000000050315800>] device_add+0x61e/0x1950
    [<0000000021008dfb>] netdev_register_kobject+0x17e/0x390
    [<00000000602704fe>] register_netdevice+0xb61/0x1250
    [<000000002b7ca244>] __tun_chr_ioctl+0x1cd1/0x3d70
    [<000000001127ca24>] ksys_ioctl+0xe5/0x130
    [<00000000b7d5e66a>] __x64_sys_ioctl+0x6f/0xb0
    [<00000000e1023498>] do_syscall_64+0x56/0xa0
    [<000000009ec0eb12>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

If call_netdevice_notifiers() failed, then rollback_registered()
calls netdev_unregister_kobject() which holds the kobject. The
reference cannot be put because the netdev won't be add to todo
list, so it will leads a memleak, we need put the reference to
avoid memleak.
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The dynamic key update for addr_list_lock still causes troubles,
for example the following race condition still exists:

CPU 0:				CPU 1:
(RCU read lock)			(RTNL lock)
dev_mc_seq_show()		netdev_update_lockdep_key()
				  -> lockdep_unregister_key()
 -> netif_addr_lock_bh()

because lockdep doesn't provide an API to update it atomically.
Therefore, we have to move it back to static keys and use subclass
for nest locking like before.

In commit 1a33e10e ("net: partially revert dynamic lockdep key
changes"), I already reverted most parts of commit ab92d68f
("net: core: add generic lockdep keys").

This patch reverts the rest and also part of commit f3b0a18b
("net: remove unnecessary variables and callback"). After this
patch, addr_list_lock changes back to using static keys and
subclasses to satisfy lockdep. Thanks to dev->lower_level, we do
not have to change back to ->ndo_get_lock_subclass().

And hopefully this reduces some syzbot lockdep noises too.

Reported-by: syzbot+f3a0e80c34b3fc28ac5e@syzkaller.appspotmail.com
Cc: Taehee Yoo <ap420073@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Sequence counters write paths are critical sections that must never be
preempted, and blocking, even for CONFIG_PREEMPTION=n, is not allowed.

Commit 5dbe7c17 ("net: fix kernel deadlock with interface rename and
netdev name retrieval.") handled a deadlock, observed with
CONFIG_PREEMPTION=n, where the devnet_rename seqcount read side was
infinitely spinning: it got scheduled after the seqcount write side
blocked inside its own critical section.

To fix that deadlock, among other issues, the commit added a
cond_resched() inside the read side section. While this will get the
non-preemptible kernel eventually unstuck, the seqcount reader is fully
exhausting its slice just spinning -- until TIF_NEED_RESCHED is set.

The fix is also still broken: if the seqcount reader belongs to a
real-time scheduling policy, it can spin forever and the kernel will
livelock.

Disabling preemption over the seqcount write side critical section will
not work: inside it are a number of GFP_KERNEL allocations and mutex
locking through the drivers/base/ :: device_rename() call chain.

>From all the above, replace the seqcount with a rwsem.

Fixes: 5dbe7c17 (net: fix kernel deadlock with interface rename and netdev name retrieval.)
Fixes: 30e6c9fa (net: devnet_rename_seq should be a seqcount)
Fixes: c91f6df2 (sockopt: Change getsockopt() of SO_BINDTODEVICE to return an interface name)
Cc: <stable@vger.kernel.org>
Reported-by: kbuild test robot <lkp@intel.com> [ v1 missing up_read() on error exit ]
Reported-by: Dan Carpenter <dan.carpenter@oracle.com> [ v1 missing up_read() on error exit ]
Signed-off-by: NAhmed S. Darwish <a.darwish@linutronix.de>
Reviewed-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add BPF_XDP_DEVMAP attach type for use with programs associated with a
DEVMAP entry.

Allow DEVMAPs to associate a program with a device entry by adding
a bpf_prog.fd to 'struct bpf_devmap_val'. Values read show the program
id, so the fd and id are a union. bpf programs can get access to the
struct via vmlinux.h.

The program associated with the fd must have type XDP with expected
attach type BPF_XDP_DEVMAP. When a program is associated with a device
index, the program is run on an XDP_REDIRECT and before the buffer is
added to the per-cpu queue. At this point rxq data is still valid; the
next patch adds tx device information allowing the prorgam to see both
ingress and egress device indices.

XDP generic is skb based and XDP programs do not work with skb's. Block
the use case by walking maps used by a program that is to be attached
via xdpgeneric and fail if any of them are DEVMAP / DEVMAP_HASH with

Block attach of BPF_XDP_DEVMAP programs to devices.
Signed-off-by: NDavid Ahern <dsahern@kernel.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20200529220716.75383-3-dsahern@kernel.orgSigned-off-by: NAlexei Starovoitov <ast@kernel.org>

__netif_receive_skb_core may change the skb pointer passed into it (e.g.
in rx_handler). The original skb may be freed as a result of this
operation.

The callers of __netif_receive_skb_core may further process original skb
by using pt_prev pointer returned by __netif_receive_skb_core thus
leading to unpleasant effects.

The solution is to pass skb by reference into __netif_receive_skb_core.

v2: Added Fixes tag and comment regarding ppt_prev and skb invariant.

Fixes: 88eb1944 ("net: core: propagate SKB lists through packet_type lookup")
Signed-off-by: NBoris Sukholitko <boris.sukholitko@broadcom.com>
Acked-by: NEdward Cree <ecree@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The SKB "head" pointer points to the data area that contains
skb_shared_info, that can be found via skb_end_pointer(). Given
xdp->data_hard_start have been established (basically pointing to
skb->head), frame size is between skb_end_pointer() and data_hard_start,
plus the size reserved to skb_shared_info.

Change the bpf_xdp_adjust_tail offset adjust of skb->len, to be a positive
offset number on grow, and negative number on shrink.  As this seems more
natural when reading the code.
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/158945336804.97035.7164852191163722056.stgit@firesoul

syzbot managed to trigger a recursive NETDEV_FEAT_CHANGE event
between bonding master and slave. I managed to find a reproducer
for this:

  ip li set bond0 up
  ifenslave bond0 eth0
  brctl addbr br0
  ethtool -K eth0 lro off
  brctl addif br0 bond0
  ip li set br0 up

When a NETDEV_FEAT_CHANGE event is triggered on a bonding slave,
it captures this and calls bond_compute_features() to fixup its
master's and other slaves' features. However, when syncing with
its lower devices by netdev_sync_lower_features() this event is
triggered again on slaves when the LRO feature fails to change,
so it goes back and forth recursively until the kernel stack is
exhausted.

Commit 17b85d29 intentionally lets __netdev_update_features()
return -1 for such a failure case, so we have to just rely on
the existing check inside netdev_sync_lower_features() and skip
NETDEV_FEAT_CHANGE event only for this specific failure case.

Fixes: fd867d51 ("net/core: generic support for disabling netdev features down stack")
Reported-by: syzbot+e73ceacfd8560cc8a3ca@syzkaller.appspotmail.com
Reported-by: syzbot+c2fb6f9ddcea95ba49b5@syzkaller.appspotmail.com
Cc: Jarod Wilson <jarod@redhat.com>
Cc: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jann Horn <jannh@google.com>
Reviewed-by: NJay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Acked-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>