Back in linux-2.6.25 (commit 4a6ad7a1 "[NETNS]: Make icmp_sk per namespace."),
we added private per-cpu/per-netns ipv4 icmp sockets.

This adds memory and cpu costs, which do not seem needed.
Now typical servers have 256 or more cores, this adds considerable
tax to netns users.

icmp sockets are used from BH context, are not receiving packets,
and do not store any persistent state but the 'struct net' pointer.

icmp_xmit_lock() already makes sure to lock the chosen per-cpu
socket.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Prior patches in the series made sure tw_timer_handler()
can be fired after netns has been dismantled/freed.

We no longer have to scan a potentially big TCP ehash
table at netns dismantle.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We will soon get rid of inet_twsk_purge().

This means that tw_timer_handler() might fire after
a netns has been dismantled/freed.

Instead of adding a function (and data structure) to find a netns
from tw->tw_net_cookie, just update the SNMP counters
a bit earlier, when the netns is known to be alive.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We want to allow inet_twsk_kill() working even if netns
has been dismantled/freed, to get rid of inet_twsk_purge().

This patch adds tw->tw_bslot to cache the bind bucket slot
so that inet_twsk_kill() no longer needs to dereference twsk_net(tw)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Shannon Nelson says:

====================
ionic: updates for stable FW recovery

Recent FW work has tightened up timings in its error recovery
handling and uncovered weaknesses in the driver's responses,
so this is a set of updates primarily for better handling of
the firmware's recovery mechanisms.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

This (ab)use of a data buffer made some static code checkers
rather itchy, so we replace the a generic data buffer with
the union in the struct ionic_vf_setattr_cmd.

Fixes: fbb39807 ("ionic: support sr-iov operations")
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

The driver can be premature in detecting stalled firmware
when the heartbeat is not updated because the firmware can
occasionally take a long time (more than 2 seconds) to service
a request, and doesn't update the heartbeat during that time.

The firmware heartbeat is not necessarily a steady 1 second
periodic beat, but better described as something that should
progress at least once in every DECVMD_TIMEOUT period.
The single-threaded design in the FW means that if a devcmd
or adminq request launches a large internal job, it is stuck
waiting for that job to finish before it can get back to
updating the heartbeat.  Since all requests are "guaranteed"
to finish within the DEVCMD_TIMEOUT period, the driver needs
to less aggressive in checking the heartbeat progress.

We change our current 2 second window to something bigger than
DEVCMD_TIMEOUT which should take care of most of the issue.
We stop checking for the heartbeat while waiting for a request,
as long as we're still watching for the FW status.  Lastly,
we make sure our FW status is up to date before running a
devcmd request.

Once we do this, we need to not check the heartbeat on DEV
commands because it may be stalled while we're on the fw_down
path.  Instead, we can rely on the is_fw_running check.

Fixes: b2b9a8d7 ("ionic: avoid races in ionic_heartbeat_check")
Signed-off-by: Brett Creeley <brett@pensando.io>
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

The dbid_inuse bitmap is not useful in this driver so remove it.

Fixes: 6461b446 ("ionic: Add interrupts and doorbells")
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

When the driver is going through reset, it will eventually call
ionic_lif_init(), which does a lot of re-initialization. One
of the re-initialization steps is to setup the adminq and
enable napi for it.  If something breaks after this point
we can end up with a kernel NULL pointer dereference through
ionic_adminq_napi.

Fix this by making sure to call napi_disable() in the cleanup
path of ionic_lif_init().  This forces any pending napi contexts
to finish and prevents them from being recalled before deleting
the napi context.

Fixes: 77ceb68e ("ionic: Add notifyq support")
Signed-off-by: Brett Creeley <brett@pensando.io>
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

Buffer DMA mapping happens in ionic_tx_map_skb() and this function is
called from ionic_tx() and ionic_tx_tso(). If ionic_tx_map_skb()
succeeds, but a failure is encountered later in ionic_tx() or
ionic_tx_tso() we aren't unmapping the buffers. This can be fixed in
ionic_tx() by changing functions it calls to return void because they
always return 0. For ionic_tx_tso(), there's an actual possibility that
we leave the buffers mapped, so fix this by introducing the helper
function ionic_tx_desc_unmap_bufs(). This function is also re-used
in ionic_tx_clean().

Fixes: 0f3154e6 ("ionic: Add Tx and Rx handling")
Signed-off-by: Brett Creeley <brett@pensando.io>
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

Currently when a request for add/deleting a filter is made when
ionic_heartbeat_check() returns failure the driver will be overly
verbose about failures, especially when these are usually temporary
fails and the request will be retried later. An example of this is
a filter add when the FW is in the middle of resetting:

IONIC_CMD_RX_FILTER_ADD (31) failed: IONIC_RC_ERROR (-6)
rx_filter add failed: ADDR 01:80:c2:00:00:0e

Fix this by checking for -ENXIO and other error values on filter
request fails before printing the error message.  Add similar
checking to the delete filter code.

Fixes: f91958cc ("ionic: tame the filter no space message")
Signed-off-by: Brett Creeley <brett@pensando.io>
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

Currently when an administrator configures a VF via ndo_set_vf*,
the driver will send the set command to FW and then update the
cached value.  The cached value is then used when reporting
VF info via ndo_get_vf_config.

A problem is that the VF info may have been updated between
the last ndo_set_vf* and ndo_get_vf_info commands via some
other method, i.e. a VF changes its MAC address (assuming it's
allowed to do so) and since this is all managed by the FW,
this new value won't be reflected in the PF's cache of values.

To fix this, update the driver to always get the latest VF
information by making use of the IONIC_CMD_VF_GETATTR dev
command. The FW may not support getting all the attributes for
IONIC_CMD_VF_GETATTR, so the driver will only update the cached
VF config members if their associated IONIC_CMD_VF_GETATTR
was successful. Otherwise the cached VF config members will
remain the same as what was set in ndo_set_vf*.

Fixes: fbb39807 ("ionic: support sr-iov operations")
Signed-off-by: Brett Creeley <brett@pensando.io>
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

When dev commands fail, an error message will always be printed,
which may be overly alarming the to system administrators,
especially if the driver shouldn't be printing the error due
to some unsupported capability.

Similar to recent adminq request changes, we can update the
dev command interface with the ability to selectively print
error messages to allow the driver to prevent printing errors
that are expected.
Signed-off-by: Brett Creeley <brett@pensando.io>
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

Recent changes went into the driver to allow flexibility when
printing error messages. Unfortunately this had the unexpected
consequence of printing confusing messages like the following:

IONIC_CMD_RX_FILTER_ADD (31) failed: IONIC_RC_SUCCESS (-6)

In cases like this the completion of the admin queue command never
completes, so the completion status is 0, hence IONIC_RC_SUCCESS
is printed even though the command clearly failed. For example,
this could happen when the driver tries to add a filter and at
the same time the FW goes through a reset, so the AQ command
never completes.

Fix this by forcing the FW completion status to IONIC_RC_ERROR
in cases where we never get the completion.

Fixes: 8c9d956a ("ionic: allow adminq requests to override default error message")
Signed-off-by: Brett Creeley <brett@pensando.io>
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

Make sure we print the TIMEOUT string if we had a timeout
error, rather than printing the wrong status.

Fixes: 8c9d956a ("ionic: allow adminq requests to override default error message")
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

When IONIC_EVENT_RESET is received, we only need to start the
fw_down process if we aren't already down, and we need to be
sure to set the FW_STOPPING state on the way.

If this is how we noticed that FW was stopped, it is most
likely from a FW update, and we'll see a new FW generation.
The update happens quickly enough that we might not see
fw_status==0, so we need to be sure things get restarted when
we see the fw_generation change.

Fixes: d2662072 ("ionic: monitor fw status generation")
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

Between fw running and fw actually stopped into reset, we need
a fw_stopping concept to catch and block some actions while
we're transitioning to FW_RESET state.  This will help to be
sure the fw_up task is not scheduled until after the fw_down
task has completed.

On some rare occasion timing, it is possible for the fw_up task
to try to run before the fw_down task, then not get run after
the fw_down task has run, leaving the device in a down state.
This is possible if the watchdog goes off in between finding the
down transition and starting the fw_down task, where the later
watchdog sees the FW is back up and schedules a fw_up task.

Fixes: c672412f ("ionic: remove lifs on fw reset")
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

It's possible the FW is already shutting down while the driver is being
removed and/or when the driver is going through reset. This can cause
unexpected/unnecessary errors to be printed:

eth0: DEV_CMD IONIC_CMD_PORT_RESET (12) error, IONIC_RC_ERROR (29) failed
eth1: DEV_CMD IONIC_CMD_RESET (3) error, IONIC_RC_ERROR (29) failed

Fix this by checking the FW status register before issuing the reset
commands.

Also, since err may not be assigned in ionic_port_reset(), assign it a
default value of 0, and remove an unnecessary log message.

Fixes: fbfb8031 ("ionic: Add hardware init and device commands")
Signed-off-by: Brett Creeley <brett@pensando.io>
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull the watchdog init code out to a separate bite-sized
function.  Code cleaning for now, will be a useful change in
the near future.
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

The watchdog expects the lif to fully exist when it goes off,
so lets not start the watchdog until all is ready in case there
is some quirky time dialation that makes probe take multiple
seconds.

Fixes: 089406bc ("ionic: add a watchdog timer to monitor heartbeat")
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

Sparse seems to have gotten a little more picky lately and
we need to revisit this bit of code to make sparse happy.

warning: incorrect type in initializer (different address spaces)
   expected union ionic_dev_cmd_regs *regs
   got union ionic_dev_cmd_regs [noderef] __iomem *dev_cmd_regs
warning: incorrect type in argument 2 (different address spaces)
   expected void [noderef] __iomem *
   got unsigned int *
warning: incorrect type in argument 1 (different address spaces)
   expected void volatile [noderef] __iomem *
   got union ionic_dev_cmd *

Fixes: d701ec32 ("ionic: clean up sparse complaints")
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use kvzalloc()/kvfree() instead of hand coded functions.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Since IPv4 routes support IPv6 gateways now, we can route IPv4 traffic in
NBMA tunnels.
Signed-off-by: Qing Deng <i@moy.cat>
Signed-off-by: David S. Miller <davem@davemloft.net>

The 2nd param of phy_init_eee(): clk_stop_enable is a bool param, use
true or false instead of 1/0.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20220123152241.1480-1-jszhang@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Variable val is being initialized with a value that is never read,
it is being re-assigned later. The assignment is redundant and
can be removed.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Link: https://lore.kernel.org/r/20220123184936.113486-1-colin.i.king@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Variable reg is being masked however the variable is never read
after this. The assignment is redundant and can be removed.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20220123184035.112785-1-colin.i.king@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Daniel Borkmann says:

====================
pull-request: bpf-next 2022-01-24

We've added 80 non-merge commits during the last 14 day(s) which contain
a total of 128 files changed, 4990 insertions(+), 895 deletions(-).

The main changes are:

1) Add XDP multi-buffer support and implement it for the mvneta driver,
   from Lorenzo Bianconi, Eelco Chaudron and Toke Høiland-Jørgensen.

2) Add unstable conntrack lookup helpers for BPF by using the BPF kfunc
   infra, from Kumar Kartikeya Dwivedi.

3) Extend BPF cgroup programs to export custom ret value to userspace via
   two helpers bpf_get_retval() and bpf_set_retval(), from YiFei Zhu.

4) Add support for AF_UNIX iterator batching, from Kuniyuki Iwashima.

5) Complete missing UAPI BPF helper description and change bpf_doc.py script
   to enforce consistent & complete helper documentation, from Usama Arif.

6) Deprecate libbpf's legacy BPF map definitions and streamline XDP APIs to
   follow tc-based APIs, from Andrii Nakryiko.

7) Support BPF_PROG_QUERY for BPF programs attached to sockmap, from Di Zhu.

8) Deprecate libbpf's bpf_map__def() API and replace users with proper getters
   and setters, from Christy Lee.

9) Extend libbpf's btf__add_btf() with an additional hashmap for strings to
   reduce overhead, from Kui-Feng Lee.

10) Fix bpftool and libbpf error handling related to libbpf's hashmap__new()
    utility function, from Mauricio Vásquez.

11) Add support to BTF program names in bpftool's program dump, from Raman Shukhau.

12) Fix resolve_btfids build to pick up host flags, from Connor O'Brien.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (80 commits)
  selftests, bpf: Do not yet switch to new libbpf XDP APIs
  selftests, xsk: Fix rx_full stats test
  bpf: Fix flexible_array.cocci warnings
  xdp: disable XDP_REDIRECT for xdp frags
  bpf: selftests: add CPUMAP/DEVMAP selftests for xdp frags
  bpf: selftests: introduce bpf_xdp_{load,store}_bytes selftest
  net: xdp: introduce bpf_xdp_pointer utility routine
  bpf: generalise tail call map compatibility check
  libbpf: Add SEC name for xdp frags programs
  bpf: selftests: update xdp_adjust_tail selftest to include xdp frags
  bpf: test_run: add xdp_shared_info pointer in bpf_test_finish signature
  bpf: introduce frags support to bpf_prog_test_run_xdp()
  bpf: move user_size out of bpf_test_init
  bpf: add frags support to xdp copy helpers
  bpf: add frags support to the bpf_xdp_adjust_tail() API
  bpf: introduce bpf_xdp_get_buff_len helper
  net: mvneta: enable jumbo frames if the loaded XDP program support frags
  bpf: introduce BPF_F_XDP_HAS_FRAGS flag in prog_flags loading the ebpf program
  net: mvneta: add frags support to XDP_TX
  xdp: add frags support to xdp_return_{buff/frame}
  ...
====================

Link: https://lore.kernel.org/r/20220124221235.18993-1-daniel@iogearbox.netSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Revert commit 54435652 ("selftests/bpf: switch to new libbpf XDP APIs")
for now given this will heavily conflict with 4b27480d ("bpf/selftests:
convert xdp_link test to ASSERT_* macros") upon merge. Andrii agreed to redo
the conversion cleanly after trees merged.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>

Merge tag 'linux-can-fixes-for-5.17-20220124' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can

Marc Kleine-Budde says:

====================
pull-request: can 2022-01-24

The first patch updates the email address of Brian Silverman from his
former employer to his private address.

The next patch fixes DT bindings information for the tcan4x5x SPI CAN
driver.

The following patch targets the m_can driver and fixes the
introduction of FIFO bulk read support.

Another patch for the tcan4x5x driver, which fixes the max register
value for the regmap config.

The last patch for the flexcan driver marks the RX mailbox support for
the MCF5441X as support.

* tag 'linux-can-fixes-for-5.17-20220124' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can:
  can: flexcan: mark RX via mailboxes as supported on MCF5441X
  can: tcan4x5x: regmap: fix max register value
  can: m_can: m_can_fifo_{read,write}: don't read or write from/to FIFO if length is 0
  dt-bindings: can: tcan4x5x: fix mram-cfg RX FIFO config
  mailmap: update email address of Brian Silverman
====================

Link: https://lore.kernel.org/r/20220124175955.3464134-1-mkl@pengutronix.deSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Most flexcan IP cores support 2 RX modes:
- FIFO
- mailbox

The flexcan IP core on the MCF5441X cannot receive CAN RTR messages
via mailboxes. However the mailbox mode is more performant. The commit

| 1c45f577 ("can: flexcan: add ethtool support to change rx-rtr setting during runtime")

added support to switch from FIFO to mailbox mode on these cores.

After testing the mailbox mode on the MCF5441X by Angelo Dureghello,
this patch marks it (without RTR capability) as supported. Further the
IP core overview table is updated, that RTR reception via mailboxes is
not supported.

Link: https://lore.kernel.org/all/20220121084425.3141218-1-mkl@pengutronix.deTested-by: Angelo Dureghello <angelo@kernel-space.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

The MRAM of the tcan4x5x has a size of 2K and starts at 0x8000. There
are no further registers in the tcan4x5x making 0x87fc the biggest
addressable register.

This patch fixes the max register value of the regmap config from
0x8ffc to 0x87fc.

Fixes: 6e1caaf8 ("can: tcan4x5x: fix max register value")
Link: https://lore.kernel.org/all/20220119064011.2943292-1-mkl@pengutronix.deSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

In order to optimize FIFO access, especially on m_can cores attached
to slow busses like SPI, in patch

| e3938177 ("can: m_can: Disable IRQs on FIFO bus errors")

bulk read/write support has been added to the m_can_fifo_{read,write}
functions.

That change leads to the tcan driver to call
regmap_bulk_{read,write}() with a length of 0 (for CAN frames with 0
data length). regmap treats this as an error:

| tcan4x5x spi1.0 tcan4x5x0: FIFO write returned -22

This patch fixes the problem by not calling the
cdev->ops->{read,write)_fifo() in case of a 0 length read/write.

Fixes: e3938177 ("can: m_can: Disable IRQs on FIFO bus errors")
Link: https://lore.kernel.org/all/20220114155751.2651888-1-mkl@pengutronix.de
Cc: stable@vger.kernel.org
Cc: Matt Kline <matt@bitbashing.io>
Cc: Chandrasekar Ramakrishnan <rcsekar@samsung.com>
Reported-by: Michael Anochin <anochin@photo-meter.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

This tcan4x5x only comes with 2K of MRAM, a RX FIFO with a dept of 32
doesn't fit into the MRAM. Use a depth of 16 instead.

Fixes: 4edd396a ("dt-bindings: can: tcan4x5x: Add DT bindings for TCAN4x5X driver")
Link: https://lore.kernel.org/all/20220119062951.2939851-1-mkl@pengutronix.deSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Brian Silverman's address at bluerivertech.com is not valid anymore,
use Brian's private email address instead.

Link: https://lore.kernel.org/all/20220110082359.2019735-1-mkl@pengutronix.de
Cc: Brian Silverman <bsilver16384@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Fix the rx_full stats test so that it correctly reports pass even when
the fill ring is not full of buffers.

Fixes: 872a1184 ("selftests: xsk: Put the same buffer only once in the fill ring")
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Link: https://lore.kernel.org/bpf/20220121123508.12759-1-magnus.karlsson@gmail.com

Zero-length and one-element arrays are deprecated, see:
Documentation/process/deprecated.rst

Flexible-array members should be used instead.

Generated by: scripts/coccinelle/misc/flexible_array.cocci

Fixes: c1ff181f ("selftests/bpf: Extend kfunc selftests")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: kernel test robot <lkp@intel.com>
Signed-off-by: Julia Lawall <julia.lawall@inria.fr>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/alpine.DEB.2.22.394.2201221206320.12220@hadrien

The tx_coalesce and mii_irq are not used at all now, so remove them.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Simplify code by using bitmap_weight() and bitmap_zero() instead of
hand-writing these functions.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When 'ping' changes to use PING socket instead of RAW socket by:

   # sysctl -w net.ipv4.ping_group_range="0 100"

the selftests 'router_broadcast.sh' will fail, as such command

  # ip vrf exec vrf-h1 ping -I veth0 198.51.100.255 -b

can't receive the response skb by the PING socket. It's caused by mismatch
of sk_bound_dev_if and dif in ping_rcv() when looking up the PING socket,
as dif is vrf-h1 if dif's master was set to vrf-h1.

This patch is to fix this regression by also checking the sk_bound_dev_if
against sdif so that the packets can stil be received even if the socket
is not bound to the vrf device but to the real iif.

Fixes: c319b4d7 ("net: ipv4: add IPPROTO_ICMP socket kind")
Reported-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We encountered a crash in smc_setsockopt() and it is caused by
accessing smc->clcsock after clcsock was released.

 BUG: kernel NULL pointer dereference, address: 0000000000000020
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: 0000 [#1] PREEMPT SMP PTI
 CPU: 1 PID: 50309 Comm: nginx Kdump: loaded Tainted: G E     5.16.0-rc4+ #53
 RIP: 0010:smc_setsockopt+0x59/0x280 [smc]
 Call Trace:
  <TASK>
  __sys_setsockopt+0xfc/0x190
  __x64_sys_setsockopt+0x20/0x30
  do_syscall_64+0x34/0x90
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7f16ba83918e
  </TASK>

This patch tries to fix it by holding clcsock_release_lock and
checking whether clcsock has already been released before access.

In case that a crash of the same reason happens in smc_getsockopt()
or smc_switch_to_fallback(), this patch also checkes smc->clcsock
in them too. And the caller of smc_switch_to_fallback() will identify
whether fallback succeeds according to the return value.

Fixes: fd57770d ("net/smc: wait for pending work before clcsock release_sock")
Link: https://lore.kernel.org/lkml/5dd7ffd1-28e2-24cc-9442-1defec27375e@linux.ibm.com/T/Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Acked-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>