net: reformat kdoc return statements

kernel-doc -Wall warns about missing Return: statement for non-void
functions. We have a number of kdocs in our headers which are missing
the colon, IOW they use

net: reformat kdoc return statements

kernel-doc -Wall warns about missing Return: statement for non-void
functions. We have a number of kdocs in our headers which are missing
the colon, IOW they use
* Return some value
or
* Returns some value

Having the colon makes some sense, it should help kdoc parser avoid
false positives. So add them. This is mostly done with a sed script,
and removing the unnecessary cases (mostly the comments which aren't
kdoc).

Acked-by: Johannes Berg <[email protected]>
Acked-by: Richard Cochran <[email protected]>
Acked-by: Sergey Ryazanov <[email protected]>
Reviewed-by: Edward Cree <[email protected]>
Acked-by: Alexandra Winter <[email protected]>
Acked-by: Pablo Neira Ayuso <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

include: net: add static inline dst_dev_overhead() to dst.h

Add static inline dst_dev_overhead() function to include/net/dst.h. This
helper function is used by ioam6_iptunnel, rpl_iptunnel and
seg6_

include: net: add static inline dst_dev_overhead() to dst.h

Add static inline dst_dev_overhead() function to include/net/dst.h. This
helper function is used by ioam6_iptunnel, rpl_iptunnel and
seg6_iptunnel to get the dev's overhead based on a cache entry
(dst_entry). If the cache is empty, the default and generic value
skb->mac_len is returned. Otherwise, LL_RESERVED_SPACE() over dst's dev
is returned.

Signed-off-by: Justin Iurman <[email protected]>
Cc: Alexander Lobakin <[email protected]>
Cc: Vadim Fedorenko <[email protected]>
Signed-off-by: Paolo Abeni <[email protected]>

show more ...

net: Correct spelling in headers

Correct spelling in Networking headers.
As reported by codespell.

Signed-off-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/20240822-net-spell-v

net: Correct spelling in headers

Correct spelling in Networking headers.
As reported by codespell.

Signed-off-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

net: dst: Make dst_destroy() static and return void.

Since commit 52df157f17e56 ("xfrm: take refcnt of dst when creating
struct xfrm_dst bundle") dst_destroy() returns only NULL and no caller
cares

net: dst: Make dst_destroy() static and return void.

Since commit 52df157f17e56 ("xfrm: take refcnt of dst when creating
struct xfrm_dst bundle") dst_destroy() returns only NULL and no caller
cares about the return value.
There are no in in-tree users of dst_destroy() outside of the file.

Make dst_destroy() static and return void.

Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>

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ipv6: drop feature RTAX_FEATURE_ALLFRAG

RTAX_FEATURE_ALLFRAG was added before the first git commit:

https://www.mail-archive.com/[email protected]/msg03399.html

The feature would sen

ipv6: drop feature RTAX_FEATURE_ALLFRAG

RTAX_FEATURE_ALLFRAG was added before the first git commit:

https://www.mail-archive.com/[email protected]/msg03399.html

The feature would send packets to the fragmentation path if a box
receives a PMTU value with less than 1280 byte. However, since commit
9d289715eb5c ("ipv6: stop sending PTB packets for MTU < 1280"), such
message would be simply discarded. The feature flag is neither supported
in iproute2 utility. In theory one can still manipulate it with direct
netlink message, but it is not ideal because it was based on obsoleted
guidance of RFC-2460 (replaced by RFC-8200).

The feature would always test false at the moment, so remove related
code or mark them as unused.

Signed-off-by: Yan Zhai <[email protected]>
Reviewed-by: Florian Westphal <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Link: https://lore.kernel.org/r/d78e44dcd9968a252143ffe78460446476a472a1.1698156966.git.yan@cloudflare.com
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

net: dst: remove unnecessary input parameter in dst_alloc and dst_init

Since commit 1202cdd66531("Remove DECnet support from kernel") has been
merged, all callers pass in the initial_ref value of 1

net: dst: remove unnecessary input parameter in dst_alloc and dst_init

Since commit 1202cdd66531("Remove DECnet support from kernel") has been
merged, all callers pass in the initial_ref value of 1 when they call
dst_alloc(). Therefore, remove initial_ref when the dst_alloc() is
declared and replace initial_ref with 1 in dst_alloc().
Also when all callers call dst_init(), the value of initial_ref is 1.
Therefore, remove the input parameter initial_ref of the dst_init() and
replace initial_ref with the value 1 in dst_init.

Signed-off-by: Zhengchao Shao <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>

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net: dst: Switch to rcuref_t reference counting

Under high contention dst_entry::__refcnt becomes a significant bottleneck.

atomic_inc_not_zero() is implemented with a cmpxchg() loop, which goes in

net: dst: Switch to rcuref_t reference counting

Under high contention dst_entry::__refcnt becomes a significant bottleneck.

atomic_inc_not_zero() is implemented with a cmpxchg() loop, which goes into
high retry rates on contention.

Switch the reference count to rcuref_t which results in a significant
performance gain. Rename the reference count member to __rcuref to reflect
the change.

The gain depends on the micro-architecture and the number of concurrent
operations and has been measured in the range of +25% to +130% with a
localhost memtier/memcached benchmark which amplifies the problem
massively.

Running the memtier/memcached benchmark over a real (1Gb) network
connection the conversion on top of the false sharing fix for struct
dst_entry::__refcnt results in a total gain in the 2%-5% range over the
upstream baseline.

Reported-by: Wangyang Guo <[email protected]>
Reported-by: Arjan Van De Ven <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

net: dst: Prevent false sharing vs. dst_entry:: __refcnt

dst_entry::__refcnt is highly contended in scenarios where many connections
happen from and to the same IP. The reference count is an atomic_

net: dst: Prevent false sharing vs. dst_entry:: __refcnt

dst_entry::__refcnt is highly contended in scenarios where many connections
happen from and to the same IP. The reference count is an atomic_t, so the
reference count operations have to take the cache-line exclusive.

Aside of the unavoidable reference count contention there is another
significant problem which is caused by that: False sharing.

perf top identified two affected read accesses. dst_entry::lwtstate and
rtable::rt_genid.

dst_entry:__refcnt is located at offset 64 of dst_entry, which puts it into
a seperate cacheline vs. the read mostly members located at the beginning
of the struct.

That prevents false sharing vs. the struct members in the first 64
bytes of the structure, but there is also

dst_entry::lwtstate

which is located after the reference count and in the same cache line. This
member is read after a reference count has been acquired.

struct rtable embeds a struct dst_entry at offset 0. struct dst_entry has a
size of 112 bytes, which means that the struct members of rtable which
follow the dst member share the same cache line as dst_entry::__refcnt.
Especially

rtable::rt_genid

is also read by the contexts which have a reference count acquired
already.

When dst_entry:__refcnt is incremented or decremented via an atomic
operation these read accesses stall. This was found when analysing the
memtier benchmark in 1:100 mode, which amplifies the problem extremly.

Move the rt[6i]_uncached[_list] members out of struct rtable and struct
rt6_info into struct dst_entry to provide padding and move the lwtstate
member after that so it ends up in the same cache line.

The resulting improvement depends on the micro-architecture and the number
of CPUs. It ranges from +20% to +120% with a localhost memtier/memcached
benchmark.

[ tglx: Rearrange struct ]

Signed-off-by: Wangyang Guo <[email protected]>
Signed-off-by: Arjan van de Ven <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Reviewed-by: David Ahern <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

net: add atomic_long_t to net_device_stats fields

Long standing KCSAN issues are caused by data-race around
some dev->stats changes.

Most performance critical paths already use per-cpu
variables, o

net: add atomic_long_t to net_device_stats fields

Long standing KCSAN issues are caused by data-race around
some dev->stats changes.

Most performance critical paths already use per-cpu
variables, or per-queue ones.

It is reasonable (and more correct) to use atomic operations
for the slow paths.

This patch adds an union for each field of net_device_stats,
so that we can convert paths that are not yet protected
by a spinlock or a mutex.

netdev_stats_to_stats64() no longer has an #if BITS_PER_LONG==64

Note that the memcpy() we were using on 64bit arches
had no provision to avoid load-tearing,
while atomic_long_read() is providing the needed protection
at no cost.

Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: Remove unused inline function dst_hold_and_use()

All uses of dst_hold_and_use() have
been removed since commit 1202cdd66531 ("Remove DECnet support
from kernel"), so remove it.

Signed-off-by:

net: Remove unused inline function dst_hold_and_use()

All uses of dst_hold_and_use() have
been removed since commit 1202cdd66531 ("Remove DECnet support
from kernel"), so remove it.

Signed-off-by: Gaosheng Cui <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

net: dst: add net device refcount tracking to dst_entry

We want to track all dev_hold()/dev_put() to ease leak hunting.

Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: Jakub Kicins

net: dst: add net device refcount tracking to dst_entry

We want to track all dev_hold()/dev_put() to ease leak hunting.

Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

sk_buff: track dst status in slow_gro

Similar to the previous patch, but covering the dst field:
the slow_gro flag is additionally set when a dst is attached
to the skb

RFC -> v1:
- use the existi

sk_buff: track dst status in slow_gro

Similar to the previous patch, but covering the dst field:
the slow_gro flag is additionally set when a dst is attached
to the skb

RFC -> v1:
- use the existing flag instead of adding a new one

Signed-off-by: Paolo Abeni <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: Consolidate common blackhole dst ops

Move generic blackhole dst ops to the core and use them from both
ipv4_dst_blackhole_ops and ip6_dst_blackhole_ops where possible. No
functional change othe

net: Consolidate common blackhole dst ops

Move generic blackhole dst ops to the core and use them from both
ipv4_dst_blackhole_ops and ip6_dst_blackhole_ops where possible. No
functional change otherwise. We need these also in other locations
and having to define them over and over again is not great.

Signed-off-by: Daniel Borkmann <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: indirect call helpers for ipv4/ipv6 dst_check functions

This patch avoids the indirect call for the common case:
ip6_dst_check and ipv4_dst_check

Signed-off-by: Brian Vazquez <[email protected]

net: indirect call helpers for ipv4/ipv6 dst_check functions

This patch avoids the indirect call for the common case:
ip6_dst_check and ipv4_dst_check

Signed-off-by: Brian Vazquez <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

net: use indirect call helpers for dst_mtu

This patch avoids the indirect call for the common case:
ip6_mtu and ipv4_mtu

Signed-off-by: Brian Vazquez <[email protected]>
Signed-off-by: Jakub Kicin

net: use indirect call helpers for dst_mtu

This patch avoids the indirect call for the common case:
ip6_mtu and ipv4_mtu

Signed-off-by: Brian Vazquez <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

net: use indirect call helpers for dst_output

This patch avoids the indirect call for the common case:
ip6_output and ip_output

Signed-off-by: Brian Vazquez <[email protected]>
Signed-off-by: Jaku

net: use indirect call helpers for dst_output

This patch avoids the indirect call for the common case:
ip6_output and ip_output

Signed-off-by: Brian Vazquez <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

net: use indirect call helpers for dst_input

This patch avoids the indirect call for the common case:
ip_local_deliver and ip6_input

Signed-off-by: Brian Vazquez <[email protected]>
Signed-off-by:

net: use indirect call helpers for dst_input

This patch avoids the indirect call for the common case:
ip_local_deliver and ip6_input

Signed-off-by: Brian Vazquez <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

mpls: drop skb's dst in mpls_forward()

Commit 394de110a733 ("net: Added pointer check for
dst->ops->neigh_lookup in dst_neigh_lookup_skb") added a test in
dst_neigh_lookup_skb() to avoid a NULL poin

mpls: drop skb's dst in mpls_forward()

Commit 394de110a733 ("net: Added pointer check for
dst->ops->neigh_lookup in dst_neigh_lookup_skb") added a test in
dst_neigh_lookup_skb() to avoid a NULL pointer dereference. The root
cause was the MPLS forwarding code, which doesn't call skb_dst_drop()
on incoming packets. That is, if the packet is received from a
collect_md device, it has a metadata_dst attached to it that doesn't
implement any dst_ops function.

To align the MPLS behaviour with IPv4 and IPv6, let's drop the dst in
mpls_forward(). This way, dst_neigh_lookup_skb() doesn't need to test
->neigh_lookup any more. Let's keep a WARN condition though, to
document the precondition and to ease detection of such problems in the
future.

Signed-off-by: Guillaume Nault <[email protected]>
Link: https://lore.kernel.org/r/f8c2784c13faa54469a2aac339470b1049ca6b63.1604102750.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

net: clean up codestyle

This is a pure codestyle cleanup patch. No functional change intended.

Signed-off-by: Miaohe Lin <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

tunnels: PMTU discovery support for directly bridged IP packets

It's currently possible to bridge Ethernet tunnels carrying IP
packets directly to external interfaces without assigning them
addresse

tunnels: PMTU discovery support for directly bridged IP packets

It's currently possible to bridge Ethernet tunnels carrying IP
packets directly to external interfaces without assigning them
addresses and routes on the bridged network itself: this is the case
for UDP tunnels bridged with a standard bridge or by Open vSwitch.

PMTU discovery is currently broken with those configurations, because
the encapsulation effectively decreases the MTU of the link, and
while we are able to account for this using PMTU discovery on the
lower layer, we don't have a way to relay ICMP or ICMPv6 messages
needed by the sender, because we don't have valid routes to it.

On the other hand, as a tunnel endpoint, we can't fragment packets
as a general approach: this is for instance clearly forbidden for
VXLAN by RFC 7348, section 4.3:

VTEPs MUST NOT fragment VXLAN packets. Intermediate routers may
fragment encapsulated VXLAN packets due to the larger frame size.
The destination VTEP MAY silently discard such VXLAN fragments.

The same paragraph recommends that the MTU over the physical network
accomodates for encapsulations, but this isn't a practical option for
complex topologies, especially for typical Open vSwitch use cases.

Further, it states that:

Other techniques like Path MTU discovery (see [RFC1191] and
[RFC1981]) MAY be used to address this requirement as well.

Now, PMTU discovery already works for routed interfaces, we get
route exceptions created by the encapsulation device as they receive
ICMP Fragmentation Needed and ICMPv6 Packet Too Big messages, and
we already rebuild those messages with the appropriate MTU and route
them back to the sender.

Add the missing bits for bridged cases:

- checks in skb_tunnel_check_pmtu() to understand if it's appropriate
to trigger a reply according to RFC 1122 section 3.2.2 for ICMP and
RFC 4443 section 2.4 for ICMPv6. This function is already called by
UDP tunnels

- a new function generating those ICMP or ICMPv6 replies. We can't
reuse icmp_send() and icmp6_send() as we don't see the sender as a
valid destination. This doesn't need to be generic, as we don't
cover any other type of ICMP errors given that we only provide an
encapsulation function to the sender

While at it, make the MTU check in skb_tunnel_check_pmtu() accurate:
we might receive GSO buffers here, and the passed headroom already
includes the inner MAC length, so we don't have to account for it
a second time (that would imply three MAC headers on the wire, but
there are just two).

This issue became visible while bridging IPv6 packets with 4500 bytes
of payload over GENEVE using IPv4 with a PMTU of 4000. Given the 50
bytes of encapsulation headroom, we would advertise MTU as 3950, and
we would reject fragmented IPv6 datagrams of 3958 bytes size on the
wire. We're exclusively dealing with network MTU here, though, so we
could get Ethernet frames up to 3964 octets in that case.

v2:
- moved skb_tunnel_check_pmtu() to ip_tunnel_core.c (David Ahern)
- split IPv4/IPv6 functions (David Ahern)

Signed-off-by: Stefano Brivio <[email protected]>
Reviewed-by: David Ahern <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: Added pointer check for dst->ops->neigh_lookup in dst_neigh_lookup_skb

The packets from tunnel devices (eg bareudp) may have only
metadata in the dst pointer of skb. Hence a pointer check of
ne

net: Added pointer check for dst->ops->neigh_lookup in dst_neigh_lookup_skb

The packets from tunnel devices (eg bareudp) may have only
metadata in the dst pointer of skb. Hence a pointer check of
neigh_lookup is needed in dst_neigh_lookup_skb

Kernel crashes when packets from bareudp device is processed in
the kernel neighbour subsytem.

[ 133.384484] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 133.385240] #PF: supervisor instruction fetch in kernel mode
[ 133.385828] #PF: error_code(0x0010) - not-present page
[ 133.386603] PGD 0 P4D 0
[ 133.386875] Oops: 0010 [#1] SMP PTI
[ 133.387275] CPU: 0 PID: 5045 Comm: ping Tainted: G W 5.8.0-rc2+ #15
[ 133.388052] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
[ 133.391076] RIP: 0010:0x0
[ 133.392401] Code: Bad RIP value.
[ 133.394029] RSP: 0018:ffffb79980003d50 EFLAGS: 00010246
[ 133.396656] RAX: 0000000080000102 RBX: ffff9de2fe0d6600 RCX: ffff9de2fe5e9d00
[ 133.399018] RDX: 0000000000000000 RSI: ffff9de2fe5e9d00 RDI: ffff9de2fc21b400
[ 133.399685] RBP: ffff9de2fe5e9d00 R08: 0000000000000000 R09: 0000000000000000
[ 133.400350] R10: ffff9de2fbc6be22 R11: ffff9de2fe0d6600 R12: ffff9de2fc21b400
[ 133.401010] R13: ffff9de2fe0d6628 R14: 0000000000000001 R15: 0000000000000003
[ 133.401667] FS: 00007fe014918740(0000) GS:ffff9de2fec00000(0000) knlGS:0000000000000000
[ 133.402412] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 133.402948] CR2: ffffffffffffffd6 CR3: 000000003bb72000 CR4: 00000000000006f0
[ 133.403611] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 133.404270] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 133.404933] Call Trace:
[ 133.405169] <IRQ>
[ 133.405367] __neigh_update+0x5a4/0x8f0
[ 133.405734] arp_process+0x294/0x820
[ 133.406076] ? __netif_receive_skb_core+0x866/0xe70
[ 133.406557] arp_rcv+0x129/0x1c0
[ 133.406882] __netif_receive_skb_one_core+0x95/0xb0
[ 133.407340] process_backlog+0xa7/0x150
[ 133.407705] net_rx_action+0x2af/0x420
[ 133.408457] __do_softirq+0xda/0x2a8
[ 133.408813] asm_call_on_stack+0x12/0x20
[ 133.409290] </IRQ>
[ 133.409519] do_softirq_own_stack+0x39/0x50
[ 133.410036] do_softirq+0x50/0x60
[ 133.410401] __local_bh_enable_ip+0x50/0x60
[ 133.410871] ip_finish_output2+0x195/0x530
[ 133.411288] ip_output+0x72/0xf0
[ 133.411673] ? __ip_finish_output+0x1f0/0x1f0
[ 133.412122] ip_send_skb+0x15/0x40
[ 133.412471] raw_sendmsg+0x853/0xab0
[ 133.412855] ? insert_pfn+0xfe/0x270
[ 133.413827] ? vvar_fault+0xec/0x190
[ 133.414772] sock_sendmsg+0x57/0x80
[ 133.415685] __sys_sendto+0xdc/0x160
[ 133.416605] ? syscall_trace_enter+0x1d4/0x2b0
[ 133.417679] ? __audit_syscall_exit+0x1d9/0x280
[ 133.418753] ? __prepare_exit_to_usermode+0x5d/0x1a0
[ 133.419819] __x64_sys_sendto+0x24/0x30
[ 133.420848] do_syscall_64+0x4d/0x90
[ 133.421768] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 133.422833] RIP: 0033:0x7fe013689c03
[ 133.423749] Code: Bad RIP value.
[ 133.424624] RSP: 002b:00007ffc7288f418 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[ 133.425940] RAX: ffffffffffffffda RBX: 000056151fc63720 RCX: 00007fe013689c03
[ 133.427225] RDX: 0000000000000040 RSI: 000056151fc63720 RDI: 0000000000000003
[ 133.428481] RBP: 00007ffc72890b30 R08: 000056151fc60500 R09: 0000000000000010
[ 133.429757] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000040
[ 133.431041] R13: 000056151fc636e0 R14: 000056151fc616bc R15: 0000000000000080
[ 133.432481] Modules linked in: mpls_iptunnel act_mirred act_tunnel_key cls_flower sch_ingress veth mpls_router ip_tunnel bareudp ip6_udp_tunnel udp_tunnel macsec udp_diag inet_diag unix_diag af_packet_diag netlink_diag binfmt_misc xt_MASQUERADE iptable_nat xt_addrtype xt_conntrack nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 br_netfilter bridge stp llc ebtable_filter ebtables overlay ip6table_filter ip6_tables iptable_filter sunrpc ext4 mbcache jbd2 pcspkr i2c_piix4 virtio_balloon joydev ip_tables xfs libcrc32c ata_generic qxl pata_acpi drm_ttm_helper ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm ata_piix libata virtio_net net_failover virtio_console failover virtio_blk i2c_core virtio_pci virtio_ring serio_raw floppy virtio dm_mirror dm_region_hash dm_log dm_mod
[ 133.444045] CR2: 0000000000000000
[ 133.445082] ---[ end trace f4aeee1958fd1638 ]---
[ 133.446236] RIP: 0010:0x0
[ 133.447180] Code: Bad RIP value.
[ 133.448152] RSP: 0018:ffffb79980003d50 EFLAGS: 00010246
[ 133.449363] RAX: 0000000080000102 RBX: ffff9de2fe0d6600 RCX: ffff9de2fe5e9d00
[ 133.450835] RDX: 0000000000000000 RSI: ffff9de2fe5e9d00 RDI: ffff9de2fc21b400
[ 133.452237] RBP: ffff9de2fe5e9d00 R08: 0000000000000000 R09: 0000000000000000
[ 133.453722] R10: ffff9de2fbc6be22 R11: ffff9de2fe0d6600 R12: ffff9de2fc21b400
[ 133.455149] R13: ffff9de2fe0d6628 R14: 0000000000000001 R15: 0000000000000003
[ 133.456520] FS: 00007fe014918740(0000) GS:ffff9de2fec00000(0000) knlGS:0000000000000000
[ 133.458046] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 133.459342] CR2: ffffffffffffffd6 CR3: 000000003bb72000 CR4: 00000000000006f0
[ 133.460782] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 133.462240] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 133.463697] Kernel panic - not syncing: Fatal exception in interrupt
[ 133.465226] Kernel Offset: 0xfa00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[ 133.467025] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---

Fixes: aaa0c23cb901 ("Fix dst_neigh_lookup/dst_neigh_lookup_skb return value handling bug")
Signed-off-by: Martin Varghese <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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Remove DST_HOST

Previous changes to the IP routing code have removed all the
tests for the DS_HOST route flag.
Remove the flags and all the code that sets it.

Signed-off-by: David Laight <david.lai

Remove DST_HOST

Previous changes to the IP routing code have removed all the
tests for the DS_HOST route flag.
Remove the flags and all the code that sets it.

Signed-off-by: David Laight <[email protected]>
Acked-by: David Ahern <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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net/dst: do not confirm neighbor for vxlan and geneve pmtu update

When do IPv6 tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end,
we should not call dst_confirm_neigh() as there is no t

net/dst: do not confirm neighbor for vxlan and geneve pmtu update

When do IPv6 tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end,
we should not call dst_confirm_neigh() as there is no two-way communication.

So disable the neigh confirm for vxlan and geneve pmtu update.

v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
dst_ops.update_pmtu to control whether we should do neighbor confirm.
Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.

Fixes: a93bf0ff4490 ("vxlan: update skb dst pmtu on tx path")
Fixes: 52a589d51f10 ("geneve: update skb dst pmtu on tx path")
Reviewed-by: Guillaume Nault <[email protected]>
Tested-by: Guillaume Nault <[email protected]>
Acked-by: David Ahern <[email protected]>
Signed-off-by: Hangbin Liu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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net/dst: add new function skb_dst_update_pmtu_no_confirm

Add a new function skb_dst_update_pmtu_no_confirm() for callers who need
update pmtu but should not do neighbor confirm.

v5: No change.
v4:

net/dst: add new function skb_dst_update_pmtu_no_confirm

Add a new function skb_dst_update_pmtu_no_confirm() for callers who need
update pmtu but should not do neighbor confirm.

v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
dst_ops.update_pmtu to control whether we should do neighbor confirm.
Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.

Reviewed-by: Guillaume Nault <[email protected]>
Acked-by: David Ahern <[email protected]>
Signed-off-by: Hangbin Liu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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net: add bool confirm_neigh parameter for dst_ops.update_pmtu

The MTU update code is supposed to be invoked in response to real
networking events that update the PMTU. In IPv6 PMTU update function
_

net: add bool confirm_neigh parameter for dst_ops.update_pmtu

The MTU update code is supposed to be invoked in response to real
networking events that update the PMTU. In IPv6 PMTU update function
__ip6_rt_update_pmtu() we called dst_confirm_neigh() to update neighbor
confirmed time.

But for tunnel code, it will call pmtu before xmit, like:
- tnl_update_pmtu()
- skb_dst_update_pmtu()
- ip6_rt_update_pmtu()
- __ip6_rt_update_pmtu()
- dst_confirm_neigh()

If the tunnel remote dst mac address changed and we still do the neigh
confirm, we will not be able to update neigh cache and ping6 remote
will failed.

So for this ip_tunnel_xmit() case, _EVEN_ if the MTU is changed, we
should not be invoking dst_confirm_neigh() as we have no evidence
of successful two-way communication at this point.

On the other hand it is also important to keep the neigh reachability fresh
for TCP flows, so we cannot remove this dst_confirm_neigh() call.

To fix the issue, we have to add a new bool parameter for dst_ops.update_pmtu
to choose whether we should do neigh update or not. I will add the parameter
in this patch and set all the callers to true to comply with the previous
way, and fix the tunnel code one by one on later patches.

v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
dst_ops.update_pmtu to control whether we should do neighbor confirm.
Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.

Suggested-by: David Miller <[email protected]>
Reviewed-by: Guillaume Nault <[email protected]>
Acked-by: David Ahern <[email protected]>
Signed-off-by: Hangbin Liu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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