net/smc: reduce sock_put() for fallback sockets

smc_release() calls a sock_put() for smc fallback sockets to cover
the passive closing sock_hold() in __smc_connect() and
smc_tcp_listen_work(). This

net/smc: reduce sock_put() for fallback sockets

smc_release() calls a sock_put() for smc fallback sockets to cover
the passive closing sock_hold() in __smc_connect() and
smc_tcp_listen_work(). This does not make sense for sockets in state
SMC_LISTEN and SMC_INIT.
An SMC socket stays in state SMC_INIT if connect fails. The sock_put
in smc_connect_abort() does not cover all failures. Move it into
smc_connect_decline_fallback().

Fixes: ee9dfbef02d18 ("net/smc: handle sockopts forcing fallback")
Reported-by: syzbot+3a0748c8f2f210c0ef9b@syzkaller.appspotmail.com
Reported-by: syzbot+9e60d2428a42049a592a@syzkaller.appspotmail.com
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net/smc: simplify wait when closing listen socket

Closing of a listen socket wakes up kernel_accept() of
smc_tcp_listen_worker(), and then has to wait till smc_tcp_listen_worker()
gives up the inter

net/smc: simplify wait when closing listen socket

Closing of a listen socket wakes up kernel_accept() of
smc_tcp_listen_worker(), and then has to wait till smc_tcp_listen_worker()
gives up the internal clcsock. The wait logic introduced with
commit 127f49705823 ("net/smc: release clcsock from tcp_listen_worker")
might wait longer than necessary. This patch implements the idea to
implement the wait just with flush_work(), and gets rid of the extra
smc_close_wait_listen_clcsock() function.

Fixes: 127f49705823 ("net/smc: release clcsock from tcp_listen_worker")
Reported-by: Hans Wippel <hwippel@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net/smc: release clcsock from tcp_listen_worker

Closing a listen socket may hit the warning
WARN_ON(sock_owned_by_user(sk)) of tcp_close(), if the wake up of
the smc_tcp_listen_worker has not yet fi

net/smc: release clcsock from tcp_listen_worker

Closing a listen socket may hit the warning
WARN_ON(sock_owned_by_user(sk)) of tcp_close(), if the wake up of
the smc_tcp_listen_worker has not yet finished.
This patch introduces smc_close_wait_listen_clcsock() making sure
the listening internal clcsock has been closed in smc_tcp_listen_work(),
before the listening external SMC socket finishes closing.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net/smc: replace sock_put worker by socket refcounting

Proper socket refcounting makes the sock_put worker obsolete.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S.

net/smc: replace sock_put worker by socket refcounting

Proper socket refcounting makes the sock_put worker obsolete.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net/smc: wake up wr_reg_wait when terminating a link group

If a new connection with a new rmb is added to a link group, its
memory region is registered. If a link group is terminated, a pending
regi

net/smc: wake up wr_reg_wait when terminating a link group

If a new connection with a new rmb is added to a link group, its
memory region is registered. If a link group is terminated, a pending
registration requires a wake up.

And consolidate setting of tx_flag peer_conn_abort in smc_lgr_terminate().

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net/smc: handle state SMC_PEERFINCLOSEWAIT correctly

A state transition from closing state SMC_PEERFINCLOSEWAIT to closing
state SMC_APPFINCLOSEWAIT is not allowed. Once a closing indication
from th

net/smc: handle state SMC_PEERFINCLOSEWAIT correctly

A state transition from closing state SMC_PEERFINCLOSEWAIT to closing
state SMC_APPFINCLOSEWAIT is not allowed. Once a closing indication
from the peer has been received, the socket reaches state SMC_CLOSED.

And receiving a peer_conn_abort just changes the state of the socket
into one of the states SMC_PROCESSABORT or SMC_CLOSED;
sending a peer_conn_abort occurs in smc_close_active() for state
SMC_PROCESSABORT only.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net/smc: cancel tx worker in case of socket aborts

If an SMC socket is aborted, the tx worker should be cancelled.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Mi

net/smc: cancel tx worker in case of socket aborts

If an SMC socket is aborted, the tx worker should be cancelled.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net/smc: improve state change handling after close wait

When a socket is closed or shutdown, smc waits for data being transmitted
in certain states. If the state changes during this wait, the close

net/smc: improve state change handling after close wait

When a socket is closed or shutdown, smc waits for data being transmitted
in certain states. If the state changes during this wait, the close
switch depending on state should be reentered.
In addition, state change is avoided if sending of close or shutdown fails.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net/smc: get rid of tx_pend waits in socket closing

There is no need to wait for confirmation of pending tx requests
for a closing connection, since pending tx slots are dismissed
when finishing a c

net/smc: get rid of tx_pend waits in socket closing

There is no need to wait for confirmation of pending tx requests
for a closing connection, since pending tx slots are dismissed
when finishing a connection.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net/smc: use local struct sock variables consistently

Cleanup to consistently exploit the local struct sock definitions.
No functional change.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com

net/smc: use local struct sock variables consistently

Cleanup to consistently exploit the local struct sock definitions.
No functional change.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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smc: make smc_close_active_abort() static

smc_close_active_abort() is used in smc_close.c only.
Make it static.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Mille

smc: make smc_close_active_abort() static

smc_close_active_abort() is used in smc_close.c only.
Make it static.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

net: smc_close: mark expected switch fall-through

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Notice that in this particular case I

net: smc_close: mark expected switch fall-through

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Notice that in this particular case I placed the "fall through" comment
on its own line, which is what GCC is expecting to find.

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net/smc: no close wait in case of process shut down

Usually socket closing is delayed if there is still data available in
the send buffer to be transmitted. If a process is killed, the delay
should

net/smc: no close wait in case of process shut down

Usually socket closing is delayed if there is still data available in
the send buffer to be transmitted. If a process is killed, the delay
should be avoided.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

net/smc: introduce a delay

The number of outstanding work requests is limited. If all work
requests are in use, tx processing is postponed to another scheduling
of the tx worker. Switch to a delayed

net/smc: introduce a delay

The number of outstanding work requests is limited. If all work
requests are in use, tx processing is postponed to another scheduling
of the tx worker. Switch to a delayed worker to have a gap for tx
completion queue events before the next retry.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

net/smc: destruct non-accepted sockets

Make sure sockets never accepted are removed cleanly.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.

net/smc: destruct non-accepted sockets

Make sure sockets never accepted are removed cleanly.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net/smc: guarantee ConnClosed send after shutdown SHUT_WR

State SMC_CLOSED should be reached only, if ConnClosed has been sent to
the peer. If ConnClosed is received from the peer, a socket with
shu

net/smc: guarantee ConnClosed send after shutdown SHUT_WR

State SMC_CLOSED should be reached only, if ConnClosed has been sent to
the peer. If ConnClosed is received from the peer, a socket with
shutdown SHUT_WR done, switches errorneously to state SMC_CLOSED, which
means the peer socket is dangling. The local SMC socket is supposed to
switch to state APPFINCLOSEWAIT to make sure smc_close_final() is called
during socket close.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net/smc: no socket state changes in tasklet context

Several state changes occur during SMC socket closing. Currently
state changes triggered locally occur in process context with
lock_sock() taken w

net/smc: no socket state changes in tasklet context

Several state changes occur during SMC socket closing. Currently
state changes triggered locally occur in process context with
lock_sock() taken while state changes triggered by peer occur in
tasklet context with bh_lock_sock() taken. bh_lock_sock() does not
wait till a lock_sock(() task in process context is finished. This
may lead to races in socket state transitions resulting in dangling
SMC-sockets, or it may lead to duplicate SMC socket freeing.
This patch introduces a closing worker to run all state changes under
lock_sock().

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

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sched/headers: Move task_struct::signal and task_struct::sighand types and accessors into <linux/sched/signal.h>

task_struct::signal and task_struct::sighand are pointers, which would normally make

sched/headers: Move task_struct::signal and task_struct::sighand types and accessors into <linux/sched/signal.h>

task_struct::signal and task_struct::sighand are pointers, which would normally make it
straightforward to not define those types in sched.h.

That is not so, because the types are accompanied by a myriad of APIs (macros and inline
functions) that dereference them.

Split the types and the APIs out of sched.h and move them into a new header, <linux/sched/signal.h>.

With this change sched.h does not know about 'struct signal' and 'struct sighand' anymore,
trying to put accessors into sched.h as a test fails the following way:

./include/linux/sched.h: In function ‘test_signal_types’:
./include/linux/sched.h:2461:18: error: dereferencing pointer to incomplete type ‘struct signal_struct’
^

This reduces the size and complexity of sched.h significantly.

Update all headers and .c code that relied on getting the signal handling
functionality from <linux/sched.h> to include <linux/sched/signal.h>.

The list of affected files in the preparatory patch was partly generated by
grepping for the APIs, and partly by doing coverage build testing, both
all[yes|mod|def|no]config builds on 64-bit and 32-bit x86, and an array of
cross-architecture builds.

Nevertheless some (trivial) build breakage is still expected related to rare
Kconfig combinations and in-flight patches to various kernel code, but most
of it should be handled by this patch.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

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smc: netlink interface for SMC sockets

Support for SMC socket monitoring via netlink sockets of protocol
NETLINK_SOCK_DIAG.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: Da

smc: netlink interface for SMC sockets

Support for SMC socket monitoring via netlink sockets of protocol
NETLINK_SOCK_DIAG.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

smc: socket closing and linkgroup cleanup

smc_shutdown() and smc_release() handling
delayed linkgroup cleanup for linkgroups without connections

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.c

smc: socket closing and linkgroup cleanup

smc_shutdown() and smc_release() handling
delayed linkgroup cleanup for linkgroups without connections

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net/smc: check variable before dereferencing in smc_close.c

smc->clcsock and smc->clcsock->sk are used before the check if they can
be dereferenced. Fix this by checking the variables fi

net/smc: check variable before dereferencing in smc_close.c

smc->clcsock and smc->clcsock->sk are used before the check if they can
be dereferenced. Fix this by checking the variables first.

Fixes: a60a2b1e0af1 ("net/smc: reduce active tcp_listen workers")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

net/smc: reduce active tcp_listen workers

SMC starts a separate tcp_listen worker for every SMC socket in
state SMC_LISTEN, and can accept an incoming connection request only,
if thi

net/smc: reduce active tcp_listen workers

SMC starts a separate tcp_listen worker for every SMC socket in
state SMC_LISTEN, and can accept an incoming connection request only,
if this worker is really running and waiting in kernel_accept(). But
the number of running workers is limited.
This patch reworks the listening SMC code and starts a tcp_listen worker
after the SYN-ACK handshake on the internal clc-socket only.

Suggested-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Reviewed-by: Guvenc Gulce <guvenc@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from David Miller:

1) Use netif_rx_ni() when necessary in batman-adv stack, from Jussi

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from David Miller:

1) Use netif_rx_ni() when necessary in batman-adv stack, from Jussi
Kivilinna.

2) Fix loss of RTT samples in rxrpc, from David Howells.

3) Memory leak in hns_nic_dev_probe(), from Dignhao Liu.

4) ravb module cannot be unloaded, fix from Yuusuke Ashizuka.

5) We disable BH for too lokng in sctp_get_port_local(), add a
cond_resched() here as well, from Xin Long.

6) Fix memory leak in st95hf_in_send_cmd, from Dinghao Liu.

7) Out of bound access in bpf_raw_tp_link_fill_link_info(), from
Yonghong Song.

8) Missing of_node_put() in mt7530 DSA driver, from Sumera
Priyadarsini.

9) Fix crash in bnxt_fw_reset_task(), from Michael Chan.

10) Fix geneve tunnel checksumming bug in hns3, from Yi Li.

11) Memory leak in rxkad_verify_response, from Dinghao Liu.

12) In tipc, don't use smp_processor_id() in preemptible context. From
Tuong Lien.

13) Fix signedness issue in mlx4 memory allocation, from Shung-Hsi Yu.

14) Missing clk_disable_prepare() in gemini driver, from Dan Carpenter.

15) Fix ABI mismatch between driver and firmware in nfp, from Louis
Peens.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (110 commits)
net/smc: fix sock refcounting in case of termination
net/smc: reset sndbuf_desc if freed
net/smc: set rx_off for SMCR explicitly
net/smc: fix toleration of fake add_link messages
tg3: Fix soft lockup when tg3_reset_task() fails.
doc: net: dsa: Fix typo in config code sample
net: dp83867: Fix WoL SecureOn password
nfp: flower: fix ABI mismatch between driver and firmware
tipc: fix shutdown() of connectionless socket
ipv6: Fix sysctl max for fib_multipath_hash_policy
drivers/net/wan/hdlc: Change the default of hard_header_len to 0
net: gemini: Fix another missing clk_disable_unprepare() in probe
net: bcmgenet: fix mask check in bcmgenet_validate_flow()
amd-xgbe: Add support for new port mode
net: usb: dm9601: Add USB ID of Keenetic Plus DSL
vhost: fix typo in error message
net: ethernet: mlx4: Fix memory allocation in mlx4_buddy_init()
pktgen: fix error message with wrong function name
net: ethernet: ti: am65-cpsw: fix rmii 100Mbit link mode
cxgb4: fix thermal zone device registration
...

show more ...

net/smc: fix sock refcounting in case of termination

When an ISM device is removed, all its linkgroups are terminated,
i.e. all the corresponding connections are killed.
Connection k

net/smc: fix sock refcounting in case of termination

When an ISM device is removed, all its linkgroups are terminated,
i.e. all the corresponding connections are killed.
Connection killing invokes smc_close_active_abort(), which decreases
the sock refcount for certain states to simulate passive closing.
And it cancels the close worker and has to give up the sock lock for
this timeframe. This opens the door for a passive close worker or a
socket close to run in between. In this case smc_close_active_abort() and
passive close worker resp. smc_release() might do a sock_put for passive
closing. This causes:

[ 1323.315943] refcount_t: underflow; use-after-free.
[ 1323.316055] WARNING: CPU: 3 PID: 54469 at lib/refcount.c:28 refcount_warn_saturate+0xe8/0x130
[ 1323.316069] Kernel panic - not syncing: panic_on_warn set ...
[ 1323.316084] CPU: 3 PID: 54469 Comm: uperf Not tainted 5.9.0-20200826.rc2.git0.46328853ed20.300.fc32.s390x+debug #1
[ 1323.316096] Hardware name: IBM 2964 NC9 702 (z/VM 6.4.0)
[ 1323.316108] Call Trace:
[ 1323.316125] [<00000000c0d4aae8>] show_stack+0x90/0xf8
[ 1323.316143] [<00000000c15989b0>] dump_stack+0xa8/0xe8
[ 1323.316158] [<00000000c0d8344e>] panic+0x11e/0x288
[ 1323.316173] [<00000000c0d83144>] __warn+0xac/0x158
[ 1323.316187] [<00000000c1597a7a>] report_bug+0xb2/0x130
[ 1323.316201] [<00000000c0d36424>] monitor_event_exception+0x44/0xc0
[ 1323.316219] [<00000000c195c716>] pgm_check_handler+0x1da/0x238
[ 1323.316234] [<00000000c151844c>] refcount_warn_saturate+0xec/0x130
[ 1323.316280] ([<00000000c1518448>] refcount_warn_saturate+0xe8/0x130)
[ 1323.316310] [<000003ff801f2e2a>] smc_release+0x192/0x1c8 [smc]
[ 1323.316323] [<00000000c169f1fa>] __sock_release+0x5a/0xe0
[ 1323.316334] [<00000000c169f2ac>] sock_close+0x2c/0x40
[ 1323.316350] [<00000000c1086de0>] __fput+0xb8/0x278
[ 1323.316362] [<00000000c0db1e0e>] task_work_run+0x76/0xb8
[ 1323.316393] [<00000000c0d8ab84>] do_exit+0x26c/0x520
[ 1323.316408] [<00000000c0d8af08>] do_group_exit+0x48/0xc0
[ 1323.316421] [<00000000c0d8afa8>] __s390x_sys_exit_group+0x28/0x38
[ 1323.316433] [<00000000c195c32c>] system_call+0xe0/0x2b4
[ 1323.316446] 1 lock held by uperf/54469:
[ 1323.316456] #0: 0000000044125e60 (&sb->s_type->i_mutex_key#9){+.+.}-{3:3}, at: __sock_release+0x44/0xe0

The patch rechecks sock state in smc_close_active_abort() after
smc_close_cancel_work() to avoid duplicate decrease of sock
refcount for the same purpose.

Fixes: 611b63a12732 ("net/smc: cancel tx worker in case of socket aborts")
Reviewed-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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