skbs in fraglist could be shared by a BPF filter loaded at TC. If TC
writes, it will call skb_ensure_writable -> pskb_expand_head to create
a private linear section for the head_skb. And then call
skb_clone_fraglist -> skb_get on each skb in the fraglist.

skb_segment_list overwrites part of the skb linear section of each
fragment itself. Even after skb_clone, the frag_skbs share their
linear section with their clone in PF_PACKET.

Both sk_receive_queue of PF_PACKET and PF_INET (or PF_INET6) can have
a link for the same frag_skbs chain. If a new skb (not frags) is
queued to one of the sk_receive_queue, multiple ptypes can see and
release this. It causes use-after-free.

[ 4443.426215] ------------[ cut here ]------------
[ 4443.426222] refcount_t: underflow; use-after-free.
[ 4443.426291] WARNING: CPU: 7 PID: 28161 at lib/refcount.c:190
refcount_dec_and_test_checked+0xa4/0xc8
[ 4443.426726] pstate: 60400005 (nZCv daif +PAN -UAO)
[ 4443.426732] pc : refcount_dec_and_test_checked+0xa4/0xc8
[ 4443.426737] lr : refcount_dec_and_test_checked+0xa0/0xc8
[ 4443.426808] Call trace:
[ 4443.426813]  refcount_dec_and_test_checked+0xa4/0xc8
[ 4443.426823]  skb_release_data+0x144/0x264
[ 4443.426828]  kfree_skb+0x58/0xc4
[ 4443.426832]  skb_queue_purge+0x64/0x9c
[ 4443.426844]  packet_set_ring+0x5f0/0x820
[ 4443.426849]  packet_setsockopt+0x5a4/0xcd0
[ 4443.426853]  __sys_setsockopt+0x188/0x278
[ 4443.426858]  __arm64_sys_setsockopt+0x28/0x38
[ 4443.426869]  el0_svc_common+0xf0/0x1d0
[ 4443.426873]  el0_svc_handler+0x74/0x98
[ 4443.426880]  el0_svc+0x8/0xc

Fixes: 3a1296a3 (net: Support GRO/GSO fraglist chaining.)
Signed-off-by: Dongseok Yi <dseok.yi@samsung.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/1610072918-174177-1-git-send-email-dseok.yi@samsung.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

At the moment it is quite hard to identify the network interface
provided by IPA in userspace components: The network interface is
created as virtual device, without any link to the IPA device.
The interface name ("rmnet_ipa%d") is the only indication that the
network interface belongs to IPA, but this is not very reliable.

Add SET_NETDEV_DEV() to associate the network interface with the
IPA parent device. This allows userspace services like ModemManager
to properly identify that this network interface is provided by IPA
and belongs to the modem.

Cc: Alex Elder <elder@kernel.org>
Fixes: a646d6ec ("soc: qcom: ipa: modem and microcontroller")
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20210106100755.56800-1-stephan@gerhold.netSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Pull more networking fixes from Jakub Kicinski:
 "Slightly lighter pull request to get back into the Thursday cadence.

  Current release - always broken:

   - can: mcp251xfd: fix Tx/Rx ring buffer driver race conditions

   - dsa: hellcreek: fix led_classdev build errors

  Previous releases - regressions:

   - ipv6: fib: flush exceptions when purging route to avoid netdev
     reference leak

   - ip_tunnels: fix pmtu check in nopmtudisc mode

   - ip: always refragment ip defragmented packets to avoid MTU issues
     when forwarding through tunnels, correct "packet too big" message
     is prohibitively tricky to generate

   - s390/qeth: fix locking for discipline setup / removal and during
     recovery to prevent both deadlocks and races

   - mlx5: Use port_num 1 instead of 0 when delete a RoCE address

  Previous releases - always broken:

   - cdc_ncm: correct overhead calculation in delayed_ndp_size to
     prevent out of bound accesses with Huawei 909s-120 LTE module

   - fix stmmac dwmac-sun8i suspend/resume:
           - PHY being left powered off
           - MAC syscon configuration being reset
           - reference to the reset controller being improperly dropped

   - qrtr: fix null-ptr-deref in qrtr_ns_remove

   - can: tcan4x5x: fix bittiming const, use common bittiming from m_can
     driver

   - mlx5e: CT: Use per flow counter when CT flow accounting is enabled

   - mlx5e: Fix SWP offsets when vlan inserted by driver

  Misc:

   - bpf: Fix a task_iter bug caused by a bpf -> net merge conflict
     resolution

  And the usual many fixes to various error paths"

* tag 'net-5.11-rc3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (69 commits)
  net: dsa: lantiq_gswip: Exclude RMII from modes that report 1 GbE
  s390/qeth: fix L2 header access in qeth_l3_osa_features_check()
  s390/qeth: fix locking for discipline setup / removal
  s390/qeth: fix deadlock during recovery
  selftests: fib_nexthops: Fix wrong mausezahn invocation
  nexthop: Bounce NHA_GATEWAY in FDB nexthop groups
  nexthop: Unlink nexthop group entry in error path
  nexthop: Fix off-by-one error in error path
  octeontx2-af: fix memory leak of lmac and lmac->name
  chtls: Fix chtls resources release sequence
  chtls: Added a check to avoid NULL pointer dereference
  chtls: Replace skb_dequeue with skb_peek
  chtls: Avoid unnecessary freeing of oreq pointer
  chtls: Fix panic when route to peer not configured
  chtls: Remove invalid set_tcb call
  chtls: Fix hardware tid leak
  net: ip: always refragment ip defragmented packets
  net: fix pmtu check in nopmtudisc mode
  selftests: netfilter: add selftest for ipip pmtu discovery with enabled connection tracking
  docs: octeontx2: tune rst markup
  ...

Pull crypto fixes from Herbert Xu:
 "This fixes a functional bug in arm/chacha-neon as well as a potential
  buffer overflow in ecdh"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: ecdh - avoid buffer overflow in ecdh_set_secret()
  crypto: arm/chacha-neon - add missing counter increment

The kernel test robot reported a -5.8% performance regression on the
"poll2" test of will-it-scale, and bisected it to commit d55564cf
("x86: Make __put_user() generate an out-of-line call").

I didn't expect an out-of-line __put_user() to matter, because no normal
core code should use that non-checking legacy version of user access any
more.  But I had overlooked the very odd poll() usage, which does a
__put_user() to update the 'revents' values of the poll array.

Now, Al Viro correctly points out that instead of updating just the
'revents' field, it would be much simpler to just copy the _whole_
pollfd entry, and then we could just use "copy_to_user()" on the whole
array of entries, the same way we use "copy_from_user()" a few lines
earlier to get the original values.

But that is not what we've traditionally done, and I worry that threaded
applications might be concurrently modifying the other fields of the
pollfd array.  So while Al's suggestion is simpler - and perhaps worth
trying in the future - this instead keeps the "just update revents"
model.

To fix the performance regression, use the modern "unsafe_put_user()"
instead of __put_user(), with the proper "user_write_access_begin()"
guarding in place. This improves code generation enormously.

Link: https://lore.kernel.org/lkml/20210107134723.GA28532@xsang-OptiPlex-9020/Reported-by: kernel test robot <oliver.sang@intel.com>
Tested-by: Oliver Sang <oliver.sang@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: David Laight <David.Laight@aculab.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This reverts commit 757055ae.

The commit caused that ttynull was used as the default console
on several systems[1][2][3]. As a result, the console was
blank even when a better alternative existed.

It happened when there was no console configured
on the command line and ttynull_init() was the first initcall
calling register_console().

Or it happened when /dev/ did not exist when console_on_rootfs()
was called. It was not able to open /dev/console even though
a console driver was registered. It tried to add ttynull console
but it obviously did not help. But ttynull became the preferred
console and was used by /dev/console when it was available later.

The commit tried to fix a historical problem that have been there
for ages. The primary motivation was the commit 3cffa06a
("printk/console: Allow to disable console output by using console=""
 or console=null"). It provided a clean solution for a workaround
 that was widely used and worked only by chance.

This revert causes that the console="" or console=null command line
options will again work only by chance. These options will cause that
a particular console will be preferred and the default (tty) ones
will not get enabled. There will be no console registered at
all. As a result there won't be stdin, stdout, and stderr for
the init process. But it worked exactly this way even before.

The proper solution has to fulfill many conditions:

  + Register ttynull only when explicitly required or as
    the ultimate fallback.

  + ttynull should get associated with /dev/console but it must
    not become preferred console when used as a fallback.
    Especially, it must still be possible to replace it
    by a better console later.

Such a change requires clean up of the register_console() code.
Otherwise, it would be even harder to follow. Especially, the use
of has_preferred_console and CON_CONSDEV flag is tricky. The clean
up is risky. The ordering of consoles is not well defined. And
any changes tend to break existing user settings.

Do the revert at the least risky solution for now.

[1] https://lore.kernel.org/linux-kselftest/20201221144302.GR4077@smile.fi.intel.com/
[2] https://lore.kernel.org/lkml/d2a3b3c0-e548-7dd1-730f-59bc5c04e191@synopsys.com/
[3] https://patchwork.ozlabs.org/project/linux-um/patch/20210105120128.10854-1-thomas@m3y3r.de/Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reported-by: Vineet Gupta <vgupta@synopsys.com>
Reported-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Saeed Mahameed says:

====================
mlx5 fixes 2021-01-07

* tag 'mlx5-fixes-2021-01-07' of git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux:
  net/mlx5e: Fix memleak in mlx5e_create_l2_table_groups
  net/mlx5e: Fix two double free cases
  net/mlx5: Release devlink object if adev fails
  net/mlx5e: ethtool, Fix restriction of autoneg with 56G
  net/mlx5e: In skb build skip setting mark in switchdev mode
  net/mlx5: E-Switch, fix changing vf VLANID
  net/mlx5e: Fix SWP offsets when vlan inserted by driver
  net/mlx5e: CT: Use per flow counter when CT flow accounting is enabled
  net/mlx5: Use port_num 1 instead of 0 when delete a RoCE address
  net/mlx5e: Add missing capability check for uplink follow
  net/mlx5: Check if lag is supported before creating one
====================

Link: https://lore.kernel.org/r/20210107202845.470205-1-saeed@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Exclude RMII from modes that report 1 GbE support. Reduced MII supports
up to 100 MbE.

Fixes: 14fceff4 ("net: dsa: Add Lantiq / Intel DSA driver for vrx200")
Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20210107195818.3878-1-olek2@wp.plSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Julian Wiedmann says:

====================
s390/qeth: fixes 2021-01-07

This brings two locking fixes for the device control path.
Also one fix for a path where our .ndo_features_check() attempts to
access a non-existent L2 header.
====================

Link: https://lore.kernel.org/r/20210107172442.1737-1-jwi@linux.ibm.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

ip_finish_output_gso() may call .ndo_features_check() even before the
skb has a L2 header. This conflicts with qeth_get_ip_version()'s attempt
to inspect the L2 header via vlan_eth_hdr().

Switch to vlan_get_protocol(), as already used further down in the
common qeth_features_check() path.

Fixes: f13ade19 ("s390/qeth: run non-offload L3 traffic over common xmit path")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Due to insufficient locking, qeth_core_set_online() and
qeth_dev_layer2_store() can run in parallel, both attempting to load &
setup the discipline (and stepping on each other toes along the way).
A similar race can also occur between qeth_core_remove_device() and
qeth_dev_layer2_store().

Access to .discipline is meant to be protected by the discipline_mutex,
so add/expand the locking in qeth_core_remove_device() and
qeth_core_set_online().
Adjust the locking in qeth_l*_remove_device() accordingly, as it's now
handled by the callers in a consistent manner.

Based on an initial patch by Ursula Braun.

Fixes: 9dc48ccc ("qeth: serialize sysfs-triggered device configurations")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

When qeth_dev_layer2_store() - holding the discipline_mutex - waits
inside qeth_l*_remove_device() for a qeth_do_reset() thread to complete,
we can hit a deadlock if qeth_do_reset() concurrently calls
qeth_set_online() and thus tries to aquire the discipline_mutex.

Move the discipline_mutex locking outside of qeth_set_online() and
qeth_set_offline(), and turn the discipline into a parameter so that
callers understand the dependency.

To fix the deadlock, we can now relax the locking:
As already established, qeth_l*_remove_device() waits for
qeth_do_reset() to complete. So qeth_do_reset() itself is under no risk
of having card->discipline ripped out while it's running, and thus
doesn't need to take the discipline_mutex.

Fixes: 9dc48ccc ("qeth: serialize sysfs-triggered device configurations")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Ido Schimmel says:

====================
nexthop: Various fixes

This series contains various fixes for the nexthop code. The bugs were
uncovered during the development of resilient nexthop groups.

Patches #1-#2 fix the error path of nexthop_create_group(). I was not
able to trigger these bugs with current code, but it is possible with
the upcoming resilient nexthop groups code which adds a user
controllable memory allocation further in the function.

Patch #3 fixes wrong validation of netlink attributes.

Patch #4 fixes wrong invocation of mausezahn in a selftest.
====================

Link: https://lore.kernel.org/r/20210107144824.1135691-1-idosch@idosch.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

For IPv6 traffic, mausezahn needs to be invoked with '-6'. Otherwise an
error is returned:

 # ip netns exec me mausezahn veth1 -B 2001:db8:101::2 -A 2001:db8:91::1 -c 0 -t tcp "dp=1-1023, flags=syn"
 Failed to set source IPv4 address. Please check if source is set to a valid IPv4 address.
  Invalid command line parameters!

Fixes: 7c741868 ("selftests: Add torture tests to nexthop tests")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

The function nh_check_attr_group() is called to validate nexthop groups.
The intention of that code seems to have been to bounce all attributes
above NHA_GROUP_TYPE except for NHA_FDB. However instead it bounces all
these attributes except when NHA_FDB attribute is present--then it accepts
them.

NHA_FDB validation that takes place before, in rtm_to_nh_config(), already
bounces NHA_OIF, NHA_BLACKHOLE, NHA_ENCAP and NHA_ENCAP_TYPE. Yet further
back, NHA_GROUPS and NHA_MASTER are bounced unconditionally.

But that still leaves NHA_GATEWAY as an attribute that would be accepted in
FDB nexthop groups (with no meaning), so long as it keeps the address
family as unspecified:

 # ip nexthop add id 1 fdb via 127.0.0.1
 # ip nexthop add id 10 fdb via default group 1

The nexthop code is still relatively new and likely not used very broadly,
and the FDB bits are newer still. Even though there is a reproducer out
there, it relies on an improbable gateway arguments "via default", "via
all" or "via any". Given all this, I believe it is OK to reformulate the
condition to do the right thing and bounce NHA_GATEWAY.

Fixes: 38428d68 ("nexthop: support for fdb ecmp nexthops")
Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

In case of error, remove the nexthop group entry from the list to which
it was previously added.

Fixes: 430a0491 ("nexthop: Add support for nexthop groups")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

A reference was not taken for the current nexthop entry, so do not try
to put it in the error path.

Fixes: 430a0491 ("nexthop: Add support for nexthop groups")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Currently the error return paths don't kfree lmac and lmac->name
leading to some memory leaks.  Fix this by adding two error return
paths that kfree these objects

Addresses-Coverity: ("Resource leak")
Fixes: 1463f382 ("octeontx2-af: Add support for CGX link management")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210107123916.189748-1-colin.king@canonical.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Ayush Sawal says:

====================
Bug fixes for chtls driver

patch 1: Fix hardware tid leak.
patch 2: Remove invalid set_tcb call.
patch 3: Fix panic when route to peer not configured.
patch 4: Avoid unnecessary freeing of oreq pointer.
patch 5: Replace skb_dequeue with skb_peek.
patch 6: Added a check to avoid NULL pointer dereference patch.
patch 7: Fix chtls resources release sequence.
====================

Link: https://lore.kernel.org/r/20210106042912.23512-1-ayush.sawal@chelsio.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

CPL_ABORT_RPL is sent after releasing the resources by calling
chtls_release_resources(sk); and chtls_conn_done(sk);
eventually causing kernel panic. Fixing it by calling release
in appropriate order.

Fixes: cc35c88a ("crypto : chtls - CPL handler definition")
Signed-off-by: Vinay Kumar Yadav <vinay.yadav@chelsio.com>
Signed-off-by: Ayush Sawal <ayush.sawal@chelsio.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

In case of server removal lookup_stid() may return NULL pointer, which
is used as listen_ctx. So added a check before accessing this pointer.

Fixes: cc35c88a ("crypto : chtls - CPL handler definition")
Signed-off-by: Vinay Kumar Yadav <vinay.yadav@chelsio.com>
Signed-off-by: Ayush Sawal <ayush.sawal@chelsio.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

The skb is unlinked twice, one in __skb_dequeue in function
chtls_reset_synq() and another in cleanup_syn_rcv_conn().
So in this patch using skb_peek() instead of __skb_dequeue(),
so that unlink will be handled only in cleanup_syn_rcv_conn().

Fixes: cc35c88a ("crypto : chtls - CPL handler definition")
Signed-off-by: Vinay Kumar Yadav <vinay.yadav@chelsio.com>
Signed-off-by: Ayush Sawal <ayush.sawal@chelsio.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

In chtls_pass_accept_request(), removing the chtls_reqsk_free()
call to avoid oreq freeing twice. Here oreq is the pointer to
struct request_sock.

Fixes: cc35c88a ("crypto : chtls - CPL handler definition")
Signed-off-by: Rohit Maheshwari <rohitm@chelsio.com>
Signed-off-by: Ayush Sawal <ayush.sawal@chelsio.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

If route to peer is not configured, we might get non tls
devices from dst_neigh_lookup() which is invalid, adding a
check to avoid it.

Fixes: cc35c88a ("crypto : chtls - CPL handler definition")
Signed-off-by: Rohit Maheshwari <rohitm@chelsio.com>
Signed-off-by: Ayush Sawal <ayush.sawal@chelsio.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

At the time of SYN_RECV, connection information is not
initialized at FW, updating tcb flag over uninitialized
connection causes adapter crash. We don't need to
update the flag during SYN_RECV state, so avoid this.

Fixes: cc35c88a ("crypto : chtls - CPL handler definition")
Signed-off-by: Rohit Maheshwari <rohitm@chelsio.com>
Signed-off-by: Ayush Sawal <ayush.sawal@chelsio.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

send_abort_rpl() is not calculating cpl_abort_req_rss offset and
ends up sending wrong TID with abort_rpl WR causng tid leaks.
Replaced send_abort_rpl() with chtls_send_abort_rpl() as it is
redundant.

Fixes: cc35c88a ("crypto : chtls - CPL handler definition")
Signed-off-by: Rohit Maheshwari <rohitm@chelsio.com>
Signed-off-by: Ayush Sawal <ayush.sawal@chelsio.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Pull gcc-plugins fix from Kees Cook:
 "Bump c++ standard version for latest GCC versions (Valdis Kletnieks)"

* tag 'gcc-plugins-v5.11-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  gcc-plugins: fix gcc 11 indigestion with plugins...

Alexei Starovoitov says:

====================
pull-request: bpf 2021-01-07

We've added 4 non-merge commits during the last 10 day(s) which contain
a total of 4 files changed, 14 insertions(+), 7 deletions(-).

The main changes are:

1) Fix task_iter bug caused by the merge conflict resolution, from Yonghong.

2) Fix resolve_btfids for multiple type hierarchies, from Jiri.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  bpftool: Fix compilation failure for net.o with older glibc
  tools/resolve_btfids: Warn when having multiple IDs for single type
  bpf: Fix a task_iter bug caused by a merge conflict resolution
  selftests/bpf: Fix a compile error for BPF_F_BPRM_SECUREEXEC
====================

Link: https://lore.kernel.org/r/20210107221555.64959-1-alexei.starovoitov@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Florian Westphal says:

====================
net: fix netfilter defrag/ip tunnel pmtu blackhole

Christian Perle reported a PMTU blackhole due to unexpected interaction
between the ip defragmentation that comes with connection tracking and
ip tunnels.

Unfortunately setting 'nopmtudisc' on the tunnel breaks the test
scenario even without netfilter.

Christinas setup looks like this:
     +--------+       +---------+       +--------+
     |Router A|-------|Wanrouter|-------|Router B|
     |        |.IPIP..|         |..IPIP.|        |
     +--------+       +---------+       +--------+
          /             mtu 1400           \
         /                                  \
 +--------+                                  +--------+
 |Client A|                                  |Client B|
 +--------+                                  +--------+

MTU is 1500 everywhere, except on Router A to Wanrouter and
Wanrouter to Router B.

Router A and Router B use IPIP tunnel interfaces to tunnel traffic
between Client A and Client B over WAN.

Client A sends a 1400 byte UDP datagram to Client B.
This packet gets encapsulated in the IPIP tunnel.

This works, packet is received on client B.

When conntrack (or anything else that forces ip defragmentation) is
enabled on Router A, the packet gets dropped on Router A after
encapsulation because they exceed the link MTU.

Setting the 'nopmtudisc' flag on the IPIP tunnel makes things worse,
no packets pass even in the no-netfilter scenario.

Patch one is a reproducer script for selftest infra.

Patch two is a fix for 'nopmtudisc' behaviour so ip_tunnel will send
an icmp error to Client A.  This allows 'nopmtudisc' tunnel to forward
the UDP datagrams.

Patch three enables ip refragmentation for all reassembled packets, just
like ipv6.
====================

Link: https://lore.kernel.org/r/20210105231523.622-1-fw@strlen.deSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Conntrack reassembly records the largest fragment size seen in IPCB.
However, when this gets forwarded/transmitted, fragmentation will only
be forced if one of the fragmented packets had the DF bit set.

In that case, a flag in IPCB will force fragmentation even if the
MTU is large enough.

This should work fine, but this breaks with ip tunnels.
Consider client that sends a UDP datagram of size X to another host.

The client fragments the datagram, so two packets, of size y and z, are
sent. DF bit is not set on any of these packets.

Middlebox netfilter reassembles those packets back to single size-X
packet, before routing decision.

packet-size-vs-mtu checks in ip_forward are irrelevant, because DF bit
isn't set.  At output time, ip refragmentation is skipped as well
because x is still smaller than the mtu of the output device.

If ttransmit device is an ip tunnel, the packet size increases to
x+overhead.

Also, tunnel might be configured to force DF bit on outer header.

In this case, packet will be dropped (exceeds MTU) and an ICMP error is
generated back to sender.

But sender already respects the announced MTU, all the packets that
it sent did fit the announced mtu.

Force refragmentation as per original sizes unconditionally so ip tunnel
will encapsulate the fragments instead.

The only other solution I see is to place ip refragmentation in
the ip_tunnel code to handle this case.

Fixes: d6b915e2 ("ip_fragment: don't forward defragmented DF packet")
Reported-by: Christian Perle <christian.perle@secunet.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

For some reason ip_tunnel insist on setting the DF bit anyway when the
inner header has the DF bit set, EVEN if the tunnel was configured with
'nopmtudisc'.

This means that the script added in the previous commit
cannot be made to work by adding the 'nopmtudisc' flag to the
ip tunnel configuration. Doing so breaks connectivity even for the
without-conntrack/netfilter scenario.

When nopmtudisc is set, the tunnel will skip the mtu check, so no
icmp error is sent to client. Then, because inner header has DF set,
the outer header gets added with DF bit set as well.

IP stack then sends an error to itself because the packet exceeds
the device MTU.

Fixes: 23a3647b ("ip_tunnels: Use skb-len to PMTU check.")
Cc: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Convert Christians bug description into a reproducer.

Cc: Shuah Khan <shuah@kernel.org>
Reported-by: Christian Perle <christian.perle@secunet.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Commit 80b94148 ("docs: octeontx2: Add Documentation for NPA health
reporters") added new documentation with improper formatting for rst, and
caused a few new warnings for make htmldocs in octeontx2.rst:169--202.

Tune markup and formatting for better presentation in the HTML view.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: George Cherian <george.cherian@marvell.com>
Link: https://lore.kernel.org/r/20210106161735.21751-1-lukas.bulwahn@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

When mlx5_create_flow_group() fails, ft->g should be
freed just like when kvzalloc() fails. The caller of
mlx5e_create_l2_table_groups() does not catch this
issue on failure, which leads to memleak.

Fixes: 33cfaaa8 ("net/mlx5e: Split the main flow steering table")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

mlx5e_create_ttc_table_groups() frees ft->g on failure of
kvzalloc(), but such failure will be caught by its caller
in mlx5e_create_ttc_table() and ft->g will be freed again
in mlx5e_destroy_flow_table(). The same issue also occurs
in mlx5e_create_ttc_table_groups(). Set ft->g to NULL after
kfree() to avoid double free.

Fixes: 7b3722fa ("net/mlx5e: Support RSS for GRE tunneled packets")
Fixes: 33cfaaa8 ("net/mlx5e: Split the main flow steering table")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

Add missed freeing previously allocated devlink object.

Fixes: a925b5e3 ("net/mlx5: Register mlx5 devices to auxiliary virtual bus")
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

Prior to this patch, configuring speed to 50G with autoneg off over
devices supporting 50G per lane failed.
Support for 50G per lane introduced a new set of link-modes, on which
driver always performed a speed validation as if only legacy link-modes
were configured. Fix driver speed validation to force setting autoneg
over 56G only if in legacy link-mode.

Fixes: 3d7cadae ("net/mlx5e: ethtool, Fix analysis of speed setting")
Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Eran Ben Elisha <eranbe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

sop_drop_qpn field in the cqe is used by two features, in SWITCHDEV mode
to restore the chain id in case of a miss and in LEGACY mode to support
skbedit mark action. In build RX skb, the skb mark field is set regardless
of the configured mode which cause a corruption of the mark field in case
of switchdev mode.

Fix by overriding the mark value back to 0 in the representor tc update
skb flow.

Fixes: 8f1e0b97 ("net/mlx5: E-Switch, Mark miss packets with new chain id mapping")
Signed-off-by: Maor Dickman <maord@nvidia.com>
Reviewed-by: Raed Salem <raeds@nvidia.com>
Reviewed-by: Oz Shlomo <ozsh@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

Adding vf VLANID for the first time, or after having cleared previously
defined VLANID works fine, however, attempting to change an existing vf
VLANID clears the rules on the firmware, but does not add new rules for
the new vf VLANID.

Fix this by changing the logic in function esw_acl_egress_lgcy_setup()
so that it will always configure egress rules.

Fixes: ea651a86 ("net/mlx5: E-Switch, Refactor eswitch egress acl codes")
Signed-off-by: Alaa Hleihel <alaa@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

In case WQE includes inline header the vlan is inserted by driver even
if vlan offload is set. On geneve over vlan interface where software
parser is used the SWP offsets should be updated according to the added
vlan.

Fixes: e3cfc7e6 ("net/mlx5e: TX, Add geneve tunnel stateless offload support")
Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>