Pull RISC-V fix from Paul Walmsley:
 "Last week, Palmer and I learned that there was an error in the RISC-V
  kernel image header format that could make it less compatible with the
  ARM64 kernel image header format. I had missed this error during my
  original reviews of the patch.

  The kernel image header format is an interface that impacts
  bootloaders, QEMU, and other user tools. Those packages must be
  updated to align with whatever is merged in the kernel. We would like
  to avoid proliferating these image formats by keeping the RISC-V
  header as close as possible to the existing ARM64 header. Since the
  arch/riscv patch that adds support for the image header was merged
  with our v5.3-rc1 pull request as commit 0f327f2a ("RISC-V: Add
  an Image header that boot loader can parse."), we think it wise to try
  to fix this error before v5.3 is released.

  The fix itself should be backwards-compatible with any project that
  has already merged support for premature versions of this interface.
  It primarily involves ensuring that the RISC-V image header has
  something useful in the same field as the ARM64 image header"

* tag 'riscv/for-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: modify the Image header to improve compatibility with the ARM64 header

Pull networking fixes from David Miller:

 1) Don't corrupt xfrm_interface parms before validation, from Nicolas
    Dichtel.

 2) Revert use of usb-wakeup in btusb, from Mario Limonciello.

 3) Block ipv6 packets in bridge netfilter if ipv6 is disabled, from
    Leonardo Bras.

 4) IPS_OFFLOAD not honored in ctnetlink, from Pablo Neira Ayuso.

 5) Missing ULP check in sock_map, from John Fastabend.

 6) Fix receive statistic handling in forcedeth, from Zhu Yanjun.

 7) Fix length of SKB allocated in 6pack driver, from Christophe
    JAILLET.

 8) ip6_route_info_create() returns an error pointer, not NULL. From
    Maciej Żenczykowski.

 9) Only add RDS sock to the hashes after rs_transport is set, from
    Ka-Cheong Poon.

10) Don't double clean TX descriptors in ixgbe, from Ilya Maximets.

11) Presence of transmit IPSEC offload in an SKB is not tested for
    correctly in ixgbe and ixgbevf. From Steffen Klassert and Jeff
    Kirsher.

12) Need rcu_barrier() when register_netdevice() takes one of the
    notifier based failure paths, from Subash Abhinov Kasiviswanathan.

13) Fix leak in sctp_do_bind(), from Mao Wenan.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (72 commits)
  cdc_ether: fix rndis support for Mediatek based smartphones
  sctp: destroy bucket if failed to bind addr
  sctp: remove redundant assignment when call sctp_get_port_local
  sctp: change return type of sctp_get_port_local
  ixgbevf: Fix secpath usage for IPsec Tx offload
  sctp: Fix the link time qualifier of 'sctp_ctrlsock_exit()'
  ixgbe: Fix secpath usage for IPsec TX offload.
  net: qrtr: fix memort leak in qrtr_tun_write_iter
  net: Fix null de-reference of device refcount
  ipv6: Fix the link time qualifier of 'ping_v6_proc_exit_net()'
  tun: fix use-after-free when register netdev failed
  tcp: fix tcp_ecn_withdraw_cwr() to clear TCP_ECN_QUEUE_CWR
  ixgbe: fix double clean of Tx descriptors with xdp
  ixgbe: Prevent u8 wrapping of ITR value to something less than 10us
  mlx4: fix spelling mistake "veify" -> "verify"
  net: hns3: fix spelling mistake "undeflow" -> "underflow"
  net: lmc: fix spelling mistake "runnin" -> "running"
  NFC: st95hf: fix spelling mistake "receieve" -> "receive"
  net/rds: An rds_sock is added too early to the hash table
  mac80211: Do not send Layer 2 Update frame before authorization
  ...

Pull MMC fixes from Ulf Hansson:

 - tmio: Fixup runtime PM management during probe and remove

 - sdhci-pci-o2micro: Fix eMMC initialization for an AMD SoC

 - bcm2835: Prevent lockups when terminating work

* tag 'mmc-v5.3-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc:
  mmc: tmio: Fixup runtime PM management during remove
  mmc: tmio: Fixup runtime PM management during probe
  Revert "mmc: tmio: move runtime PM enablement to the driver implementations"
  Revert "mmc: sdhci: Remove unneeded quirk2 flag of O2 SD host controller"
  Revert "mmc: bcm2835: Terminate timeout work synchronously"

Pull drm fixes from Dave Airlie:
 "From the maintainer summit, just some last minute fixes for final:

  lima:
   - fix gem_wait ioctl

  core:
   - constify modes list

  i915:
   - DP MST high color depth regression
   - GPU hangs on vulkan compute workloads"

* tag 'drm-fixes-2019-09-13' of git://anongit.freedesktop.org/drm/drm:
  drm/lima: fix lima_gem_wait() return value
  drm/i915: Restore relaxed padding (OCL_OOB_SUPPRES_ENABLE) for skl+
  drm/i915: Limit MST to <= 8bpc once again
  drm/modes: Make the whitelist more const

Part of the intention during the definition of the RISC-V kernel image
header was to lay the groundwork for a future merge with the ARM64
image header.  One error during my original review was not noticing
that the RISC-V header's "magic" field was at a different size and
position than the ARM64's "magic" field.  If the existing ARM64 Image
header parsing code were to attempt to parse an existing RISC-V kernel
image header format, it would see a magic number 0.  This is
undesirable, since it's our intention to align as closely as possible
with the ARM64 header format.  Another problem was that the original
"res3" field was not being initialized correctly to zero.

Address these issues by creating a 32-bit "magic2" field in the RISC-V
header which matches the ARM64 "magic" field.  RISC-V binaries will
store "RSC\x05" in this field.  The intention is that the use of the
existing 64-bit "magic" field in the RISC-V header will be deprecated
over time.  Increment the minor version number of the file format to
indicate this change, and update the documentation accordingly.  Fix
the assembler directives in head.S to ensure that reserved fields are
properly zero-initialized.
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Reported-by: Palmer Dabbelt <palmer@sifive.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Cc: Atish Patra <atish.patra@wdc.com>
Cc: Karsten Merker <merker@debian.org>
Link: https://lore.kernel.org/linux-riscv/194c2f10c9806720623430dbf0cc59a965e50448.camel@wdc.com/T/#u
Link: https://lore.kernel.org/linux-riscv/mhng-755b14c4-8f35-4079-a7ff-e421fd1b02bc@palmer-si-x1e/T/#t

A Mediatek based smartphone owner reports problems with USB
tethering in Linux.  The verbose USB listing shows a rndis_host
interface pair (e0/01/03 + 10/00/00), but the driver fails to
bind with

[  355.960428] usb 1-4: bad CDC descriptors

The problem is a failsafe test intended to filter out ACM serial
functions using the same 02/02/ff class/subclass/protocol as RNDIS.
The serial functions are recognized by their non-zero bmCapabilities.

No RNDIS function with non-zero bmCapabilities were known at the time
this failsafe was added. But it turns out that some Wireless class
RNDIS functions are using the bmCapabilities field. These functions
are uniquely identified as RNDIS by their class/subclass/protocol, so
the failing test can safely be disabled.  The same applies to the two
types of Misc class RNDIS functions.

Applying the failsafe to Communication class functions only retains
the original functionality, and fixes the problem for the Mediatek based
smartphone.

Tow examples of CDC functional descriptors with non-zero bmCapabilities
from Wireless class RNDIS functions are:

0e8d:000a  Mediatek Crosscall Spider X5 3G Phone

      CDC Header:
        bcdCDC               1.10
      CDC ACM:
        bmCapabilities       0x0f
          connection notifications
          sends break
          line coding and serial state
          get/set/clear comm features
      CDC Union:
        bMasterInterface        0
        bSlaveInterface         1
      CDC Call Management:
        bmCapabilities       0x03
          call management
          use DataInterface
        bDataInterface          1

and

19d2:1023  ZTE K4201-z

      CDC Header:
        bcdCDC               1.10
      CDC ACM:
        bmCapabilities       0x02
          line coding and serial state
      CDC Call Management:
        bmCapabilities       0x03
          call management
          use DataInterface
        bDataInterface          1
      CDC Union:
        bMasterInterface        0
        bSlaveInterface         1

The Mediatek example is believed to apply to most smartphones with
Mediatek firmware.  The ZTE example is most likely also part of a larger
family of devices/firmwares.
Suggested-by: Lars Melin <larsm17@gmail.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>

Mao Wenan says:

====================
fix memory leak for sctp_do_bind

First two patches are to do cleanup, remove redundant assignment,
and change return type of sctp_get_port_local.
Third patch is to fix memory leak for sctp_do_bind if failed
to bind address.

v2: add one patch to change return type of sctp_get_port_local.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

There is one memory leak bug report:
BUG: memory leak
unreferenced object 0xffff8881dc4c5ec0 (size 40):
  comm "syz-executor.0", pid 5673, jiffies 4298198457 (age 27.578s)
  hex dump (first 32 bytes):
    02 00 00 00 81 88 ff ff 00 00 00 00 00 00 00 00  ................
    f8 63 3d c1 81 88 ff ff 00 00 00 00 00 00 00 00  .c=.............
  backtrace:
    [<0000000072006339>] sctp_get_port_local+0x2a1/0xa00 [sctp]
    [<00000000c7b379ec>] sctp_do_bind+0x176/0x2c0 [sctp]
    [<000000005be274a2>] sctp_bind+0x5a/0x80 [sctp]
    [<00000000b66b4044>] inet6_bind+0x59/0xd0 [ipv6]
    [<00000000c68c7f42>] __sys_bind+0x120/0x1f0 net/socket.c:1647
    [<000000004513635b>] __do_sys_bind net/socket.c:1658 [inline]
    [<000000004513635b>] __se_sys_bind net/socket.c:1656 [inline]
    [<000000004513635b>] __x64_sys_bind+0x3e/0x50 net/socket.c:1656
    [<0000000061f2501e>] do_syscall_64+0x72/0x2e0 arch/x86/entry/common.c:296
    [<0000000003d1e05e>] entry_SYSCALL_64_after_hwframe+0x49/0xbe

This is because in sctp_do_bind, if sctp_get_port_local is to
create hash bucket successfully, and sctp_add_bind_addr failed
to bind address, e.g return -ENOMEM, so memory leak found, it
needs to destroy allocated bucket.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Mao Wenan <maowenan@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There are more parentheses in if clause when call sctp_get_port_local
in sctp_do_bind, and redundant assignment to 'ret'. This patch is to
do cleanup.
Signed-off-by: Mao Wenan <maowenan@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Currently sctp_get_port_local() returns a long
which is either 0,1 or a pointer casted to long.
It's neither of the callers use the return value since
commit 62208f12 ("net: sctp: simplify sctp_get_port").
Now two callers are sctp_get_port and sctp_do_bind,
they actually assumend a casted to an int was the same as
a pointer casted to a long, and they don't save the return
value just check whether it is zero or non-zero, so
it would better change return type from long to int for
sctp_get_port_local.
Signed-off-by: Mao Wenan <maowenan@huawei.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Port the same fix for ixgbe to ixgbevf.

The ixgbevf driver currently does IPsec Tx offloading
based on an existing secpath. However, the secpath
can also come from the Rx side, in this case it is
misinterpreted for Tx offload and the packets are
dropped with a "bad sa_idx" error. Fix this by using
the xfrm_offload() function to test for Tx offload.

CC: Shannon Nelson <snelson@pensando.io>
Fixes: 7f68d430 ("ixgbevf: enable VF IPsec offload operations")
Reported-by: Jonathan Tooker <jonathan@reliablehosting.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

Accessing the device when it may be runtime suspended is a bug, which is
the case in tmio_mmc_host_remove(). Let's fix the behaviour.

Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>

The tmio_mmc_host_probe() calls pm_runtime_set_active() to update the
runtime PM status of the device, as to make it reflect the current status
of the HW. This works fine for most cases, but unfortunate not for all.
Especially, there is a generic problem when the device has a genpd attached
and that genpd have the ->start|stop() callbacks assigned.

More precisely, if the driver calls pm_runtime_set_active() during
->probe(), genpd does not get to invoke the ->start() callback for it,
which means the HW isn't really fully powered on. Furthermore, in the next
phase, when the device becomes runtime suspended, genpd will invoke the
->stop() callback for it, potentially leading to usage count imbalance
problems, depending on what's implemented behind the callbacks of course.

To fix this problem, convert to call pm_runtime_get_sync() from
tmio_mmc_host_probe() rather than pm_runtime_set_active(). Additionally, to
avoid bumping usage counters and unnecessary re-initializing the HW the
first time the tmio driver's ->runtime_resume() callback is called,
introduce a state flag to keeping track of this.

Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>

This reverts commit 7ff21319.

It turns out that the above commit introduces other problems. For example,
calling pm_runtime_set_active() must not be done prior calling
pm_runtime_enable() as that makes it fail. This leads to additional
problems, such as clock enables being wrongly balanced.

Rather than fixing the problem on top, let's start over by doing a revert.

Fixes: 7ff21319 ("mmc: tmio: move runtime PM enablement to the driver implementations")
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>

Pull cgroup fix from Tejun Heo:
 "Roman found and fixed a bug in the cgroup2 freezer which allows new
  child cgroup to escape frozen state"

* 'for-5.3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: freezer: fix frozen state inheritance
  kselftests: cgroup: add freezer mkdir test

Pull btrfs fixes from David Sterba:
 "Here are two fixes, one of them urgent fixing a bug introduced in 5.2
  and reported by many users. It took time to identify the root cause,
  catching the 5.3 release is higly desired also to push the fix to 5.2
  stable tree.

  The bug is a mess up of return values after adding proper error
  handling and honestly the kind of bug that can cause sleeping
  disorders until it's caught. My appologies to everybody who was
  affected.

  Summary of what could happen:

  1) either a hang when committing a transaction, if this happens
     there's no risk of corruption, still the hang is very inconvenient
     and can't be resolved without a reboot

  2) writeback for some btree nodes may never be started and we end up
     committing a transaction without noticing that, this is really
     serious and that will lead to the "parent transid verify failed"
     messages"

* tag 'for-5.3-rc8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  Btrfs: fix unwritten extent buffers and hangs on future writeback attempts
  Btrfs: fix assertion failure during fsync and use of stale transaction

If a new child cgroup is created in the frozen cgroup hierarchy
(one or more of ancestor cgroups is frozen), the CGRP_FREEZE cgroup
flag should be set. Otherwise if a process will be attached to the
child cgroup, it won't become frozen.

The problem can be reproduced with the test_cgfreezer_mkdir test.

This is the output before this patch:
  ~/test_freezer
  ok 1 test_cgfreezer_simple
  ok 2 test_cgfreezer_tree
  ok 3 test_cgfreezer_forkbomb
  Cgroup /sys/fs/cgroup/cg_test_mkdir_A/cg_test_mkdir_B isn't frozen
  not ok 4 test_cgfreezer_mkdir
  ok 5 test_cgfreezer_rmdir
  ok 6 test_cgfreezer_migrate
  ok 7 test_cgfreezer_ptrace
  ok 8 test_cgfreezer_stopped
  ok 9 test_cgfreezer_ptraced
  ok 10 test_cgfreezer_vfork

And with this patch:
  ~/test_freezer
  ok 1 test_cgfreezer_simple
  ok 2 test_cgfreezer_tree
  ok 3 test_cgfreezer_forkbomb
  ok 4 test_cgfreezer_mkdir
  ok 5 test_cgfreezer_rmdir
  ok 6 test_cgfreezer_migrate
  ok 7 test_cgfreezer_ptrace
  ok 8 test_cgfreezer_stopped
  ok 9 test_cgfreezer_ptraced
  ok 10 test_cgfreezer_vfork
Reported-by: Mark Crossen <mcrossen@fb.com>
Signed-off-by: Roman Gushchin <guro@fb.com>
Fixes: 76f969e8 ("cgroup: cgroup v2 freezer")
Cc: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Tejun Heo <tj@kernel.org>

Add a new cgroup freezer selftest, which checks that if a cgroup is
frozen, their new child cgroups will properly inherit the frozen
state.

It creates a parent cgroup, freezes it, creates a child cgroup
and populates it with a dummy process. Then it checks that both
parent and child cgroup are frozen.
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

The userptr put_pages can be called from inside try_to_unmap, and so
enters with the page lock held on one of the object's backing pages. We
cannot take the page lock ourselves for fear of recursion.
Reported-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reported-by: Martin Wilck <Martin.Wilck@suse.com>
Reported-by: Leo Kraav <leho@kraav.com>
Fixes: aa56a292 ("drm/i915/userptr: Acquire the page lock around set_page_dirty()")
References: https://bugzilla.kernel.org/show_bug.cgi?id=203317Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull clone3 fix from Christian Brauner:
 "This is a last-minute bugfix for clone3() that should go in before we
  release 5.3 with clone3().

  clone3() did not verify that the exit_signal argument was set to a
  valid signal. This can be used to cause a crash by specifying a signal
  greater than NSIG. e.g. -1.

  The commit from Eugene adds a check to copy_clone_args_from_user() to
  verify that the exit signal is limited by CSIGNAL as with legacy
  clone() and that the signal is valid. With this we don't get the
  legacy clone behavior were an invalid signal could be handed down and
  would only be detected and then ignored in do_notify_parent(). Users
  of clone3() will now get a proper error right when they pass an
  invalid exit signal. Note, that this is not a change in user-visible
  behavior since no kernel with clone3() has been released yet"

* tag 'for-linus-20190912' of gitolite.kernel.org:pub/scm/linux/kernel/git/brauner/linux:
  fork: block invalid exit signals with clone3()

Pull x86 fixes from Ingo Molnar:
 "A KVM guest fix, and a kdump kernel relocation errors fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/timer: Force PIT initialization when !X86_FEATURE_ARAT
  x86/purgatory: Change compiler flags from -mcmodel=kernel to -mcmodel=large to fix kexec relocation errors

drm-misc-fixes for v5.3 final:
- Constify modes whitelist harder.
- Fix lima driver gem_wait ioctl.
Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/99e52e7a-d4ce-6a2c-0501-bc559a710955@linux.intel.com

Merge tag 'drm-intel-fixes-2019-09-11' of git://anongit.freedesktop.org/drm/drm-intel into drm-fixes

Final drm/i915 fixes for v5.3:
- Fox DP MST high color depth regression
- Fix GPU hangs on Vulkan compute workloads
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/877e6e27qm.fsf@intel.com

Previously, higher 32 bits of exit_signal fields were lost when copied
to the kernel args structure (that uses int as a type for the respective
field). Moreover, as Oleg has noted, exit_signal is used unchecked, so
it has to be checked for sanity before use; for the legacy syscalls,
applying CSIGNAL mask guarantees that it is at least non-negative;
however, there's no such thing is done in clone3() code path, and that
can break at least thread_group_leader.

This commit adds a check to copy_clone_args_from_user() to verify that
the exit signal is limited by CSIGNAL as with legacy clone() and that
the signal is valid. With this we don't get the legacy clone behavior
were an invalid signal could be handed down and would only be detected
and ignored in do_notify_parent(). Users of clone3() will now get a
proper error when they pass an invalid exit signal. Note, that this is
not user-visible behavior since no kernel with clone3() has been
released yet.

The following program will cause a splat on a non-fixed clone3() version
and will fail correctly on a fixed version:

 #define _GNU_SOURCE
 #include <linux/sched.h>
 #include <linux/types.h>
 #include <sched.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/syscall.h>
 #include <sys/wait.h>
 #include <unistd.h>

 int main(int argc, char *argv[])
 {
        pid_t pid = -1;
        struct clone_args args = {0};
        args.exit_signal = -1;

        pid = syscall(__NR_clone3, &args, sizeof(struct clone_args));
        if (pid < 0)
                exit(EXIT_FAILURE);

        if (pid == 0)
                exit(EXIT_SUCCESS);

        wait(NULL);

        exit(EXIT_SUCCESS);
 }

Fixes: 7f192e3c ("fork: add clone3")
Reported-by: Oleg Nesterov <oleg@redhat.com>
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Suggested-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Link: https://lore.kernel.org/r/4b38fa4ce420b119a4c6345f42fe3cec2de9b0b5.1568223594.git.esyr@redhat.com
[christian.brauner@ubuntu.com: simplify check and rework commit message]
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

The '.exit' functions from 'pernet_operations' structure should be marked
as __net_exit, not __net_init.

Fixes: 8e2d61e0 ("sctp: fix race on protocol/netns initialization")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The ixgbe driver currently does IPsec TX offloading
based on an existing secpath. However, the secpath
can also come from the RX side, in this case it is
misinterpreted for TX offload and the packets are
dropped with a "bad sa_idx" error. Fix this by using
the xfrm_offload() function to test for TX offload.

Fixes: 59259470 ("ixgbe: process the Tx ipsec offload")
Reported-by: Michael Marley <michael@michaelmarley.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The lock_extent_buffer_io() returns 1 to the caller to tell it everything
went fine and the callers needs to start writeback for the extent buffer
(submit a bio, etc), 0 to tell the caller everything went fine but it does
not need to start writeback for the extent buffer, and a negative value if
some error happened.

When it's about to return 1 it tries to lock all pages, and if a try lock
on a page fails, and we didn't flush any existing bio in our "epd", it
calls flush_write_bio(epd) and overwrites the return value of 1 to 0 or
an error. The page might have been locked elsewhere, not with the goal
of starting writeback of the extent buffer, and even by some code other
than btrfs, like page migration for example, so it does not mean the
writeback of the extent buffer was already started by some other task,
so returning a 0 tells the caller (btree_write_cache_pages()) to not
start writeback for the extent buffer. Note that epd might currently have
either no bio, so flush_write_bio() returns 0 (success) or it might have
a bio for another extent buffer with a lower index (logical address).

Since we return 0 with the EXTENT_BUFFER_WRITEBACK bit set on the
extent buffer and writeback is never started for the extent buffer,
future attempts to writeback the extent buffer will hang forever waiting
on that bit to be cleared, since it can only be cleared after writeback
completes. Such hang is reported with a trace like the following:

  [49887.347053] INFO: task btrfs-transacti:1752 blocked for more than 122 seconds.
  [49887.347059]       Not tainted 5.2.13-gentoo #2
  [49887.347060] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [49887.347062] btrfs-transacti D    0  1752      2 0x80004000
  [49887.347064] Call Trace:
  [49887.347069]  ? __schedule+0x265/0x830
  [49887.347071]  ? bit_wait+0x50/0x50
  [49887.347072]  ? bit_wait+0x50/0x50
  [49887.347074]  schedule+0x24/0x90
  [49887.347075]  io_schedule+0x3c/0x60
  [49887.347077]  bit_wait_io+0x8/0x50
  [49887.347079]  __wait_on_bit+0x6c/0x80
  [49887.347081]  ? __lock_release.isra.29+0x155/0x2d0
  [49887.347083]  out_of_line_wait_on_bit+0x7b/0x80
  [49887.347084]  ? var_wake_function+0x20/0x20
  [49887.347087]  lock_extent_buffer_for_io+0x28c/0x390
  [49887.347089]  btree_write_cache_pages+0x18e/0x340
  [49887.347091]  do_writepages+0x29/0xb0
  [49887.347093]  ? kmem_cache_free+0x132/0x160
  [49887.347095]  ? convert_extent_bit+0x544/0x680
  [49887.347097]  filemap_fdatawrite_range+0x70/0x90
  [49887.347099]  btrfs_write_marked_extents+0x53/0x120
  [49887.347100]  btrfs_write_and_wait_transaction.isra.4+0x38/0xa0
  [49887.347102]  btrfs_commit_transaction+0x6bb/0x990
  [49887.347103]  ? start_transaction+0x33e/0x500
  [49887.347105]  transaction_kthread+0x139/0x15c

So fix this by not overwriting the return value (ret) with the result
from flush_write_bio(). We also need to clear the EXTENT_BUFFER_WRITEBACK
bit in case flush_write_bio() returns an error, otherwise it will hang
any future attempts to writeback the extent buffer, and undo all work
done before (set back EXTENT_BUFFER_DIRTY, etc).

This is a regression introduced in the 5.2 kernel.

Fixes: 2e3c2513 ("btrfs: extent_io: add proper error handling to lock_extent_buffer_for_io()")
Fixes: f4340622 ("btrfs: extent_io: Move the BUG_ON() in flush_write_bio() one level up")
Reported-by: Zdenek Sojka <zsojka@seznam.cz>
Link: https://lore.kernel.org/linux-btrfs/GpO.2yos.3WGDOLpx6t%7D.1TUDYM@seznam.cz/T/#uReported-by: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>
Link: https://lore.kernel.org/linux-btrfs/5c4688ac-10a7-fb07-70e8-c5d31a3fbb38@profihost.ag/T/#tReported-by: Drazen Kacar <drazen.kacar@oradian.com>
Link: https://lore.kernel.org/linux-btrfs/DB8PR03MB562876ECE2319B3E579590F799C80@DB8PR03MB5628.eurprd03.prod.outlook.com/
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204377Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Sometimes when fsync'ing a file we need to log that other inodes exist and
when we need to do that we acquire a reference on the inodes and then drop
that reference using iput() after logging them.

That generally is not a problem except if we end up doing the final iput()
(dropping the last reference) on the inode and that inode has a link count
of 0, which can happen in a very short time window if the logging path
gets a reference on the inode while it's being unlinked.

In that case we end up getting the eviction callback, btrfs_evict_inode(),
invoked through the iput() call chain which needs to drop all of the
inode's items from its subvolume btree, and in order to do that, it needs
to join a transaction at the helper function evict_refill_and_join().
However because the task previously started a transaction at the fsync
handler, btrfs_sync_file(), it has current->journal_info already pointing
to a transaction handle and therefore evict_refill_and_join() will get
that transaction handle from btrfs_join_transaction(). From this point on,
two different problems can happen:

1) evict_refill_and_join() will often change the transaction handle's
   block reserve (->block_rsv) and set its ->bytes_reserved field to a
   value greater than 0. If evict_refill_and_join() never commits the
   transaction, the eviction handler ends up decreasing the reference
   count (->use_count) of the transaction handle through the call to
   btrfs_end_transaction(), and after that point we have a transaction
   handle with a NULL ->block_rsv (which is the value prior to the
   transaction join from evict_refill_and_join()) and a ->bytes_reserved
   value greater than 0. If after the eviction/iput completes the inode
   logging path hits an error or it decides that it must fallback to a
   transaction commit, the btrfs fsync handle, btrfs_sync_file(), gets a
   non-zero value from btrfs_log_dentry_safe(), and because of that
   non-zero value it tries to commit the transaction using a handle with
   a NULL ->block_rsv and a non-zero ->bytes_reserved value. This makes
   the transaction commit hit an assertion failure at
   btrfs_trans_release_metadata() because ->bytes_reserved is not zero but
   the ->block_rsv is NULL. The produced stack trace for that is like the
   following:

   [192922.917158] assertion failed: !trans->bytes_reserved, file: fs/btrfs/transaction.c, line: 816
   [192922.917553] ------------[ cut here ]------------
   [192922.917922] kernel BUG at fs/btrfs/ctree.h:3532!
   [192922.918310] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC PTI
   [192922.918666] CPU: 2 PID: 883 Comm: fsstress Tainted: G        W         5.1.4-btrfs-next-47 #1
   [192922.919035] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014
   [192922.919801] RIP: 0010:assfail.constprop.25+0x18/0x1a [btrfs]
   (...)
   [192922.920925] RSP: 0018:ffffaebdc8a27da8 EFLAGS: 00010286
   [192922.921315] RAX: 0000000000000051 RBX: ffff95c9c16a41c0 RCX: 0000000000000000
   [192922.921692] RDX: 0000000000000000 RSI: ffff95cab6b16838 RDI: ffff95cab6b16838
   [192922.922066] RBP: ffff95c9c16a41c0 R08: 0000000000000000 R09: 0000000000000000
   [192922.922442] R10: ffffaebdc8a27e70 R11: 0000000000000000 R12: ffff95ca731a0980
   [192922.922820] R13: 0000000000000000 R14: ffff95ca84c73338 R15: ffff95ca731a0ea8
   [192922.923200] FS:  00007f337eda4e80(0000) GS:ffff95cab6b00000(0000) knlGS:0000000000000000
   [192922.923579] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   [192922.923948] CR2: 00007f337edad000 CR3: 00000001e00f6002 CR4: 00000000003606e0
   [192922.924329] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
   [192922.924711] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
   [192922.925105] Call Trace:
   [192922.925505]  btrfs_trans_release_metadata+0x10c/0x170 [btrfs]
   [192922.925911]  btrfs_commit_transaction+0x3e/0xaf0 [btrfs]
   [192922.926324]  btrfs_sync_file+0x44c/0x490 [btrfs]
   [192922.926731]  do_fsync+0x38/0x60
   [192922.927138]  __x64_sys_fdatasync+0x13/0x20
   [192922.927543]  do_syscall_64+0x60/0x1c0
   [192922.927939]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
   (...)
   [192922.934077] ---[ end trace f00808b12068168f ]---

2) If evict_refill_and_join() decides to commit the transaction, it will
   be able to do it, since the nested transaction join only increments the
   transaction handle's ->use_count reference counter and it does not
   prevent the transaction from getting committed. This means that after
   eviction completes, the fsync logging path will be using a transaction
   handle that refers to an already committed transaction. What happens
   when using such a stale transaction can be unpredictable, we are at
   least having a use-after-free on the transaction handle itself, since
   the transaction commit will call kmem_cache_free() against the handle
   regardless of its ->use_count value, or we can end up silently losing
   all the updates to the log tree after that iput() in the logging path,
   or using a transaction handle that in the meanwhile was allocated to
   another task for a new transaction, etc, pretty much unpredictable
   what can happen.

In order to fix both of them, instead of using iput() during logging, use
btrfs_add_delayed_iput(), so that the logging path of fsync never drops
the last reference on an inode, that step is offloaded to a safe context
(usually the cleaner kthread).

The assertion failure issue was sporadically triggered by the test case
generic/475 from fstests, which loads the dm error target while fsstress
is running, which lead to fsync failing while logging inodes with -EIO
errors and then trying later to commit the transaction, triggering the
assertion failure.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

In qrtr_tun_write_iter the allocated kbuf should be release in case of
error or success return.

v2 Update: Thanks to David Miller for pointing out the release on success
path as well.
Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In event of failure during register_netdevice, free_netdev is
invoked immediately. free_netdev assumes that all the netdevice
refcounts have been dropped prior to it being called and as a
result frees and clears out the refcount pointer.

However, this is not necessarily true as some of the operations
in the NETDEV_UNREGISTER notifier handlers queue RCU callbacks for
invocation after a grace period. The IPv4 callback in_dev_rcu_put
tries to access the refcount after free_netdev is called which
leads to a null de-reference-

44837.761523:   <6> Unable to handle kernel paging request at
                    virtual address 0000004a88287000
44837.761651:   <2> pc : in_dev_finish_destroy+0x4c/0xc8
44837.761654:   <2> lr : in_dev_finish_destroy+0x2c/0xc8
44837.762393:   <2> Call trace:
44837.762398:   <2>  in_dev_finish_destroy+0x4c/0xc8
44837.762404:   <2>  in_dev_rcu_put+0x24/0x30
44837.762412:   <2>  rcu_nocb_kthread+0x43c/0x468
44837.762418:   <2>  kthread+0x118/0x128
44837.762424:   <2>  ret_from_fork+0x10/0x1c

Fix this by waiting for the completion of the call_rcu() in
case of register_netdevice errors.

Fixes: 93ee31f1 ("[NET]: Fix free_netdev on register_netdev failure.")
Cc: Sean Tranchetti <stranche@codeaurora.org>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

The '.exit' functions from 'pernet_operations' structure should be marked
as __net_exit, not __net_init.

Fixes: d862e546 ("net: ipv6: Implement /proc/net/icmp6.")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

I got a UAF repport in tun driver when doing fuzzy test:

[  466.269490] ==================================================================
[  466.271792] BUG: KASAN: use-after-free in tun_chr_read_iter+0x2ca/0x2d0
[  466.271806] Read of size 8 at addr ffff888372139250 by task tun-test/2699
[  466.271810]
[  466.271824] CPU: 1 PID: 2699 Comm: tun-test Not tainted 5.3.0-rc1-00001-g5a9433db2614-dirty #427
[  466.271833] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
[  466.271838] Call Trace:
[  466.271858]  dump_stack+0xca/0x13e
[  466.271871]  ? tun_chr_read_iter+0x2ca/0x2d0
[  466.271890]  print_address_description+0x79/0x440
[  466.271906]  ? vprintk_func+0x5e/0xf0
[  466.271920]  ? tun_chr_read_iter+0x2ca/0x2d0
[  466.271935]  __kasan_report+0x15c/0x1df
[  466.271958]  ? tun_chr_read_iter+0x2ca/0x2d0
[  466.271976]  kasan_report+0xe/0x20
[  466.271987]  tun_chr_read_iter+0x2ca/0x2d0
[  466.272013]  do_iter_readv_writev+0x4b7/0x740
[  466.272032]  ? default_llseek+0x2d0/0x2d0
[  466.272072]  do_iter_read+0x1c5/0x5e0
[  466.272110]  vfs_readv+0x108/0x180
[  466.299007]  ? compat_rw_copy_check_uvector+0x440/0x440
[  466.299020]  ? fsnotify+0x888/0xd50
[  466.299040]  ? __fsnotify_parent+0xd0/0x350
[  466.299064]  ? fsnotify_first_mark+0x1e0/0x1e0
[  466.304548]  ? vfs_write+0x264/0x510
[  466.304569]  ? ksys_write+0x101/0x210
[  466.304591]  ? do_preadv+0x116/0x1a0
[  466.304609]  do_preadv+0x116/0x1a0
[  466.309829]  do_syscall_64+0xc8/0x600
[  466.309849]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  466.309861] RIP: 0033:0x4560f9
[  466.309875] Code: 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
[  466.309889] RSP: 002b:00007ffffa5166e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000127
[  466.322992] RAX: ffffffffffffffda RBX: 0000000000400460 RCX: 00000000004560f9
[  466.322999] RDX: 0000000000000003 RSI: 00000000200008c0 RDI: 0000000000000003
[  466.323007] RBP: 00007ffffa516700 R08: 0000000000000004 R09: 0000000000000000
[  466.323014] R10: 0000000000000000 R11: 0000000000000206 R12: 000000000040cb10
[  466.323021] R13: 0000000000000000 R14: 00000000006d7018 R15: 0000000000000000
[  466.323057]
[  466.323064] Allocated by task 2605:
[  466.335165]  save_stack+0x19/0x80
[  466.336240]  __kasan_kmalloc.constprop.8+0xa0/0xd0
[  466.337755]  kmem_cache_alloc+0xe8/0x320
[  466.339050]  getname_flags+0xca/0x560
[  466.340229]  user_path_at_empty+0x2c/0x50
[  466.341508]  vfs_statx+0xe6/0x190
[  466.342619]  __do_sys_newstat+0x81/0x100
[  466.343908]  do_syscall_64+0xc8/0x600
[  466.345303]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  466.347034]
[  466.347517] Freed by task 2605:
[  466.348471]  save_stack+0x19/0x80
[  466.349476]  __kasan_slab_free+0x12e/0x180
[  466.350726]  kmem_cache_free+0xc8/0x430
[  466.351874]  putname+0xe2/0x120
[  466.352921]  filename_lookup+0x257/0x3e0
[  466.354319]  vfs_statx+0xe6/0x190
[  466.355498]  __do_sys_newstat+0x81/0x100
[  466.356889]  do_syscall_64+0xc8/0x600
[  466.358037]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  466.359567]
[  466.360050] The buggy address belongs to the object at ffff888372139100
[  466.360050]  which belongs to the cache names_cache of size 4096
[  466.363735] The buggy address is located 336 bytes inside of
[  466.363735]  4096-byte region [ffff888372139100, ffff88837213a100)
[  466.367179] The buggy address belongs to the page:
[  466.368604] page:ffffea000dc84e00 refcount:1 mapcount:0 mapping:ffff8883df1b4f00 index:0x0 compound_mapcount: 0
[  466.371582] flags: 0x2fffff80010200(slab|head)
[  466.372910] raw: 002fffff80010200 dead000000000100 dead000000000122 ffff8883df1b4f00
[  466.375209] raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000
[  466.377778] page dumped because: kasan: bad access detected
[  466.379730]
[  466.380288] Memory state around the buggy address:
[  466.381844]  ffff888372139100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  466.384009]  ffff888372139180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  466.386131] >ffff888372139200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  466.388257]                                                  ^
[  466.390234]  ffff888372139280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  466.392512]  ffff888372139300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[  466.394667] ==================================================================

tun_chr_read_iter() accessed the memory which freed by free_netdev()
called by tun_set_iff():

        CPUA                                           CPUB
  tun_set_iff()
    alloc_netdev_mqs()
    tun_attach()
                                                  tun_chr_read_iter()
                                                    tun_get()
                                                    tun_do_read()
                                                      tun_ring_recv()
    register_netdevice() <-- inject error
    goto err_detach
    tun_detach_all() <-- set RCV_SHUTDOWN
    free_netdev() <-- called from
                     err_free_dev path
      netdev_freemem() <-- free the memory
                        without check refcount
      (In this path, the refcount cannot prevent
       freeing the memory of dev, and the memory
       will be used by dev_put() called by
       tun_chr_read_iter() on CPUB.)
                                                     (Break from tun_ring_recv(),
                                                     because RCV_SHUTDOWN is set)
                                                   tun_put()
                                                     dev_put() <-- use the memory
                                                                   freed by netdev_freemem()

Put the publishing of tfile->tun after register_netdevice(),
so tun_get() won't get the tun pointer that freed by
err_detach path if register_netdevice() failed.

Fixes: eb0fb363 ("tuntap: attach queue 0 before registering netdevice")
Reported-by: Hulk Robot <hulkci@huawei.com>
Suggested-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull virtio fixes from Michael Tsirkin:
 "Last minute bugfixes.

  A couple of security things.

  And an error handling bugfix that is never encountered by most people,
  but that also makes it kind of safe to push at the last minute, and it
  helps push the fix to stable a bit sooner"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost: make sure log_num < in_num
  vhost: block speculation of translated descriptors
  virtio_ring: fix unmap of indirect descriptors

Pull perf fix from Ingo Molnar:
 "Fix an initialization bug in the hw-breakpoints, which triggered on
  the ARM platform"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/hw_breakpoint: Fix arch_hw_breakpoint use-before-initialization

Pull irq fix from Ingo Molnar:
 "Fix a race in the IRQ resend mechanism, which can result in a NULL
  dereference crash"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Prevent NULL pointer dereference in resend_irqs()

Pull pin control fix from Linus Walleij:
 "Hopefully last pin control fix: a single patch for some Aspeed
  problems. The BMCs are much happier now"

* tag 'pinctrl-v5.3-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
  pinctrl: aspeed: Fix spurious mux failures on the AST2500

Pull GPIO fixes from Linus Walleij:
 "I don't really like to send so many fixes at the very last minute, but
  the bug-sport activity is unpredictable.

  Four fixes, three are -stable material that will go everywhere, one is
  for the current cycle:

   - An ACPI DSDT error fixup of the type we always see and Hans
     invariably gets to fix.

   - A OF quirk fix for the current release (v5.3)

   - Some consistency checks on the userspace ABI.

   - A memory leak"

* tag 'gpio-v5.3-6' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
  gpiolib: acpi: Add gpiolib_acpi_run_edge_events_on_boot option and blacklist
  gpiolib: of: fix fallback quirks handling
  gpio: fix line flag validation in lineevent_create
  gpio: fix line flag validation in linehandle_create
  gpio: mockup: add missing single_release()

Commit 674fa8da ("pinctrl: aspeed-g5: Delay acquisition of regmaps")
was determined to be a partial fix to the problem of acquiring the LPC
Host Controller and GFX regmaps: The AST2500 pin controller may need to
fetch syscon regmaps during expression evaluation as well as when
setting mux state. For example, this case is hit by attempting to export
pins exposing the LPC Host Controller as GPIOs.

An optional eval() hook is added to the Aspeed pinmux operation struct
and called from aspeed_sig_expr_eval() if the pointer is set by the
SoC-specific driver. This enables the AST2500 to perform the custom
action of acquiring its regmap dependencies as required.

John Wang tested the fix on an Inspur FP5280G2 machine (AST2500-based)
where the issue was found, and I've booted the fix on Witherspoon
(AST2500) and Palmetto (AST2400) machines, and poked at relevant pins
under QEMU by forcing mux configurations via devmem before exporting
GPIOs to exercise the driver.

Fixes: 7d29ed88 ("pinctrl: aspeed: Read and write bits in LPC and GFX controllers")
Fixes: 674fa8da ("pinctrl: aspeed-g5: Delay acquisition of regmaps")
Reported-by: John Wang <wangzqbj@inspur.com>
Tested-by: John Wang <wangzqbj@inspur.com>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>

Link: https://lore.kernel.org/r/20190829071738.2523-1-andrew@aj.id.auSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

Jeff Kirsher says:

====================
Intel Wired LAN Driver Updates 2019-09-11

This series contains fixes to ixgbe.

Alex fixes up the adaptive ITR scheme for ixgbe which could result in a
value that was either 0 or something less than 10 which was causing
issues with hardware features, like RSC, that do not function well with
ITR values that low.

Ilya Maximets fixes the ixgbe driver to limit the number of transmit
descriptors to clean by the number of transmit descriptors used in the
transmit ring, so that the driver does not try to "double" clean the
same descriptors.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Fix tcp_ecn_withdraw_cwr() to clear the correct bit:
TCP_ECN_QUEUE_CWR.

Rationale: basically, TCP_ECN_DEMAND_CWR is a bit that is purely about
the behavior of data receivers, and deciding whether to reflect
incoming IP ECN CE marks as outgoing TCP th->ece marks. The
TCP_ECN_QUEUE_CWR bit is purely about the behavior of data senders,
and deciding whether to send CWR. The tcp_ecn_withdraw_cwr() function
is only called from tcp_undo_cwnd_reduction() by data senders during
an undo, so it should zero the sender-side state,
TCP_ECN_QUEUE_CWR. It does not make sense to stop the reflection of
incoming CE bits on incoming data packets just because outgoing
packets were spuriously retransmitted.

The bug has been reproduced with packetdrill to manifest in a scenario
with RFC3168 ECN, with an incoming data packet with CE bit set and
carrying a TCP timestamp value that causes cwnd undo. Before this fix,
the IP CE bit was ignored and not reflected in the TCP ECE header bit,
and sender sent a TCP CWR ('W') bit on the next outgoing data packet,
even though the cwnd reduction had been undone.  After this fix, the
sender properly reflects the CE bit and does not set the W bit.

Note: the bug actually predates 2005 git history; this Fixes footer is
chosen to be the oldest SHA1 I have tested (from Sep 2007) for which
the patch applies cleanly (since before this commit the code was in a
.h file).

Fixes: bdf1ee5d ("[TCP]: Move code from tcp_ecn.h to tcp*.c and tcp.h & remove it")
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>