This patch implements the feature that the tracing_max_latency file,
e.g. /sys/kernel/debug/tracing/tracing_max_latency will receive
notifications through the fsnotify framework when a new latency is
available.

One particularly interesting use of this facility is when enabling
threshold tracing, through /sys/kernel/debug/tracing/tracing_thresh,
together with the preempt/irqsoff tracers. This makes it possible to
implement a user space program that can, with equal probability,
obtain traces of latencies that occur immediately after each other in
spite of the fact that the preempt/irqsoff tracers operate in overwrite
mode.

This facility works with the hwlat, preempt/irqsoff, and wakeup
tracers.

The tracers may call the latency_fsnotify() from places such as
__schedule() or do_idle(); this makes it impossible to call
queue_work() directly without risking a deadlock. The same would
happen with a softirq,  kernel thread or tasklet. For this reason we
use the irq_work mechanism to call queue_work().

This patch creates a new workqueue. The reason for doing this is that
I wanted to use the WQ_UNBOUND and WQ_HIGHPRI flags.  My thinking was
that WQ_UNBOUND might help with the latency in some important cases.

If we use:

queue_work(system_highpri_wq, &tr->fsnotify_work);

then the work will (almost) always execute on the same CPU but if we are
unlucky that CPU could be too busy while there could be another CPU in
the system that would be able to process the work soon enough.

queue_work_on() could be used to queue the work on another CPU but it
seems difficult to select the right CPU.

Link: http://lkml.kernel.org/r/20191008220824.7911-2-viktor.rosendahl@gmail.comReviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Viktor Rosendahl (BMW) <viktor.rosendahl@gmail.com>
[ Added max() to have one compare for max latency ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Looking for ways to shrink the size of the dyn_ftrace structure, knowing the
information about how many pages and the number of groups of those pages, is
useful in working out the best ways to save on memory.

This adds one info print on how many groups of pages were used to allocate
the ftrace dyn_ftrace structures, and also shows the number of pages and
groups in the dyn_ftrace_total_info (which is used for debugging).
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Objtool complains about the new ftrace direct trampoline code:

  arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_regs_caller()+0x190: stack state mismatch: cfa1=7+16 cfa2=7+24

Typically, code has a deterministic stack layout, such that at a given
instruction address, the stack frame size is always the same.

That's not the case for the new ftrace_regs_caller() code after it
adjusts the stack for the direct case.  Just plead ignorance and assume
it's always the non-direct path.  Note this creates a tiny window for
ORC to get confused.

Link: http://lkml.kernel.org/r/20191108225100.ea3bhsbdf6oerj6g@trebleReported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

As testing for direct calls from the function graph tracer adds a little
overhead (which is a lot when tracing every function), add a counter that
can be used to test if function_graph tracer needs to test for a direct
caller or not.

It would have been nicer if we could use a static branch, but the static
branch logic fails when used within the function graph tracer trampoline.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Enable x86 to allow for register_ftrace_direct(), where a custom trampoline
may be called directly from an ftrace mcount/fentry location.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

The register_ftrace_direct() takes a different path if there's already a
direct call registered, but this was not tested in the self tests. Now that
there's a second direct caller test module, we can use this to test not only
one direct caller, but two.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Add another module sample that registers a direct trampoline to a function
via register_ftrace_direct(). Having another module that does this allows to
test the use case of multiple direct callers registered, as more than one
direct caller goes into another path, and is needed to perform proper
testing of the register_ftrace_direct() call.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Add two test cases that test the new ftrace direct functionality if the
ftrace-direct sample module is available. One test case tests against each
available tracer (function, function_graph, mmiotrace, etc), and the other
test tests against a kprobe at the same location as the direct caller. Both
tests follow the same pattern of testing combinations:

  enable test (either the tracer or the kprobe)
  load direct function module
  unload direct function module
  disable test

  enable test
  load direct function module
  disable test
  unload direct function module

  load direct function module
  enable test
  disable test
  unload direct function module

  load direct function module
  enable test
  unload direct function module
  disable test

As most the bugs in development happened with various ways of enabling or
disabling the direct calls with function tracer in one of these
combinations.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Add a sample module that shows a simple use case for
regsiter_ftrace_direct(), and how to use it.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

As function_graph tracer modifies the return address to insert a trampoline
to trace the return of a function, it must be aware of a direct caller, as
when it gets called, the function's return address may not be at on the
stack where it expects. It may have to see if that return address points to
the a direct caller and adjust if it is.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Add the start of the functionality to allow other trampolines to use the
ftrace mcount/fentry/nop location. This adds two new functions:

 register_ftrace_direct() and unregister_ftrace_direct()

Both take two parameters: the first is the instruction address of where the
mcount/fentry/nop exists, and the second is the trampoline to have that
location called.

This will handle cases where ftrace is already used on that same location,
and will make it still work, where the registered direct called trampoline
will get called after all the registered ftrace callers are handled.

Currently, it will not allow for IP_MODIFY functions to be called at the
same locations, which include some kprobes and live kernel patching.

At this point, no architecture supports this. This is only the start of
implementing the framework.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Create a new function called lookup_rec() from the functionality of
ftrace_location_range(). The difference between lookup_rec() is that it
returns the record that it finds, where as ftrace_location_range() returns
only if it found a match or not.

The lookup_rec() is static, and can be used for new functionality where
ftrace needs to find a record of a specific address.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Most of the functionality of __ftrace_hash_move() can be reused, but not all
of it. That is, __ftrace_hash_move() is used to simply make a new hash from
an existing one, using the same size as the original. Creating a dup_hash(),
where we can specify a new size will be useful when we want to create a hash
with a default size, or simply copy the old one.
Signed-off-by: Steven Rostedt (VMWare) <rostedt@goodmis.org>

Since livepatching depends upon ftrace handlers to implement "patched"
code functionality, verify that the ftrace_enabled sysctl value
interacts with livepatch registration as expected.  At the same time,
ensure that ftrace_enabled is set and part of the test environment
configuration that is saved and restored when running the selftests.

Link: http://lkml.kernel.org/r/20191016113316.13415-4-mbenes@suse.czSigned-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Livepatch selftests currently save the current dynamic debug config and
tweak it for the selftests. The config is restored at the end. Make the
infrastructure generic, so that more variables can be saved and
restored.

Link: http://lkml.kernel.org/r/20191016113316.13415-3-mbenes@suse.czSigned-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Livepatch uses ftrace for redirection to new patched functions. It means
that if ftrace is disabled, all live patched functions are disabled as
well. Toggling global 'ftrace_enabled' sysctl thus affect it directly.
It is not a problem per se, because only administrator can set sysctl
values, but it still may be surprising.

Introduce PERMANENT ftrace_ops flag to amend this. If the
FTRACE_OPS_FL_PERMANENT is set on any ftrace ops, the tracing cannot be
disabled by disabling ftrace_enabled. Equally, a callback with the flag
set cannot be registered if ftrace_enabled is disabled.

Link: http://lkml.kernel.org/r/20191016113316.13415-2-mbenes@suse.czReviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull USB fixes from Greg KH:
 "The USB sub-maintainers woke up this past week and sent a bunch of
  tiny fixes. Here are a lot of small patches that that resolve a bunch
  of reported issues in the USB core, drivers, serial drivers, gadget
  drivers, and of course, xhci :)

  All of these have been in linux-next with no reported issues"

* tag 'usb-5.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (31 commits)
  usb: dwc3: gadget: fix race when disabling ep with cancelled xfers
  usb: cdns3: gadget: Fix g_audio use case when connected to Super-Speed host
  usb: cdns3: gadget: reset EP_CLAIMED flag while unloading
  USB: serial: whiteheat: fix line-speed endianness
  USB: serial: whiteheat: fix potential slab corruption
  USB: gadget: Reject endpoints with 0 maxpacket value
  UAS: Revert commit 3ae62a42 ("UAS: fix alignment of scatter/gather segments")
  usb-storage: Revert commit 747668db ("usb-storage: Set virt_boundary_mask to avoid SG overflows")
  usbip: Fix free of unallocated memory in vhci tx
  usbip: tools: Fix read_usb_vudc_device() error path handling
  usb: xhci: fix __le32/__le64 accessors in debugfs code
  usb: xhci: fix Immediate Data Transfer endianness
  xhci: Fix use-after-free regression in xhci clear hub TT implementation
  USB: ldusb: fix control-message timeout
  USB: ldusb: use unsigned size format specifiers
  USB: ldusb: fix ring-buffer locking
  USB: Skip endpoints with 0 maxpacket length
  usb: cdns3: gadget: Don't manage pullups
  usb: dwc3: remove the call trace of USBx_GFLADJ
  usb: gadget: configfs: fix concurrent issue between composite APIs
  ...

Pull cifs fix from Steve French:
 "A small smb3 memleak fix"

* tag '5.4-rc6-smb3-fix' of git://git.samba.org/sfrench/cifs-2.6:
  fix memory leak in large read decrypt offload

Merge tag 'hwmon-for-v5.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fixes from Guenter Roeck:

 - Fix read timeout problem in ina3221 driver

 - Fix wrong bitmask in nct7904 driver

* tag 'hwmon-for-v5.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (ina3221) Fix read timeout issue
  hwmon: (nct7904) Fix the incorrect value of vsen_mask & tcpu_mask & temp_mode in nct7904_data struct.

Merge tag 'pwm/for-5.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm fixes from Thierry Reding:
 "It turned out that relying solely on drivers storing all the PWM state
  in hardware was a little premature and causes a number of subtle (and
  some not so subtle) regressions. Revert the offending patch for now"

* tag 'pwm/for-5.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
  Revert "pwm: Let pwm_get_state() return the last implemented state"

Pull SCSI fixes from James Bottomley:
 "Nine changes, eight in drivers [ufs, target, lpfc x 2, qla2xxx x 4]
  and one core change in sd that fixes an I/O failure on DIF type 3
  devices"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: qla2xxx: stop timer in shutdown path
  scsi: sd: define variable dif as unsigned int instead of bool
  scsi: target: cxgbit: Fix cxgbit_fw4_ack()
  scsi: qla2xxx: Fix partial flash write of MBI
  scsi: qla2xxx: Initialized mailbox to prevent driver load failure
  scsi: lpfc: Honor module parameter lpfc_use_adisc
  scsi: ufs-bsg: Wake the device before sending raw upiu commands
  scsi: lpfc: Check queue pointer before use
  scsi: qla2xxx: fixup incorrect usage of host_byte

Pull powerpc fixes from Michael Ellerman:
 "Our recent cleanup of EEH led to an oops on bare metal machines when
  the cxl (CAPI) driver creates virtual devices for an attached FPGA
  accelerator.

  The "secure virtual machine" support we added in v5.4 had a bug if the
  kernel was relocated (moved during boot), in those cases the signature
  of the kernel text wouldn't verify and the Ultravisor would refuse to
  run the VM.

  A recent change to disable interrupts before calling
  arch_cpu_idle_dead() caused a WARN_ON() in our bare metal CPU offline
  code to always trigger.

  The KUAP (SMAP) support we added for 32-bit Book3S had a bug if the
  address range crossed a segment (256MB) boundary which could lead to
  spurious faults.

  Thanks to: Christophe Leroy, Frederic Barrat, Michael Anderson,
  Nicholas Piggin, Sam Bobroff, Thiago Jung Bauermann"

* tag 'powerpc-5.4-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/powernv: Fix CPU idle to be called with IRQs disabled
  powerpc/prom_init: Undo relocation before entering secure mode
  powerpc/powernv/eeh: Fix oops when probing cxl devices
  powerpc/32s: fix allow/prevent_user_access() when crossing segment boundaries.

Pull s390 fixes from Vasily Gorbik:

 - Fix cpu idle time accounting

 - Fix stack unwinder case when both pt_regs and sp are specified

 - Fix information leak via cmm timeout proc handler

* tag 's390-5.4-6' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/idle: fix cpu idle time calculation
  s390/unwind: fix mixing regs and sp
  s390/cmm: fix information leak in cmm_timeout_handler()

Pull networking fixes from David Miller:

 1) Fix free/alloc races in batmanadv, from Sven Eckelmann.

 2) Several leaks and other fixes in kTLS support of mlx5 driver, from
    Tariq Toukan.

 3) BPF devmap_hash cost calculation can overflow on 32-bit, from Toke
    Høiland-Jørgensen.

 4) Add an r8152 device ID, from Kazutoshi Noguchi.

 5) Missing include in ipv6's addrconf.c, from Ben Dooks.

 6) Use siphash in flow dissector, from Eric Dumazet. Attackers can
    easily infer the 32-bit secret otherwise etc.

 7) Several netdevice nesting depth fixes from Taehee Yoo.

 8) Fix several KCSAN reported errors, from Eric Dumazet. For example,
    when doing lockless skb_queue_empty() checks, and accessing
    sk_napi_id/sk_incoming_cpu lockless as well.

 9) Fix jumbo packet handling in RXRPC, from David Howells.

10) Bump SOMAXCONN and tcp_max_syn_backlog values, from Eric Dumazet.

11) Fix DMA synchronization in gve driver, from Yangchun Fu.

12) Several bpf offload fixes, from Jakub Kicinski.

13) Fix sk_page_frag() recursion during memory reclaim, from Tejun Heo.

14) Fix ping latency during high traffic rates in hisilicon driver, from
    Jiangfent Xiao.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (146 commits)
  net: fix installing orphaned programs
  net: cls_bpf: fix NULL deref on offload filter removal
  selftests: bpf: Skip write only files in debugfs
  selftests: net: reuseport_dualstack: fix uninitalized parameter
  r8169: fix wrong PHY ID issue with RTL8168dp
  net: dsa: bcm_sf2: Fix IMP setup for port different than 8
  net: phylink: Fix phylink_dbg() macro
  gve: Fixes DMA synchronization.
  inet: stop leaking jiffies on the wire
  ixgbe: Remove duplicate clear_bit() call
  Documentation: networking: device drivers: Remove stray asterisks
  e1000: fix memory leaks
  i40e: Fix receive buffer starvation for AF_XDP
  igb: Fix constant media auto sense switching when no cable is connected
  net: ethernet: arc: add the missed clk_disable_unprepare
  igb: Enable media autosense for the i350.
  igb/igc: Don't warn on fatal read failures when the device is removed
  tcp: increase tcp_max_syn_backlog max value
  net: increase SOMAXCONN to 4096
  netdevsim: Fix use-after-free during device dismantle
  ...

Pull NFS client bugfixes from Anna Schumaker:
 "This contains two delegation fixes (with the RCU lock leak fix marked
  for stable), and three patches to fix destroying the the sunrpc back
  channel.

  Stable bugfixes:

   - Fix an RCU lock leak in nfs4_refresh_delegation_stateid()

  Other fixes:

   - The TCP back channel mustn't disappear while requests are
     outstanding

   - The RDMA back channel mustn't disappear while requests are
     outstanding

   - Destroy the back channel when we destroy the host transport

   - Don't allow a cached open with a revoked delegation"

* tag 'nfs-for-5.4-3' of git://git.linux-nfs.org/projects/anna/linux-nfs:
  NFS: Fix an RCU lock leak in nfs4_refresh_delegation_stateid()
  NFSv4: Don't allow a cached open with a revoked delegation
  SUNRPC: Destroy the back channel when we destroy the host transport
  SUNRPC: The RDMA back channel mustn't disappear while requests are outstanding
  SUNRPC: The TCP back channel mustn't disappear while requests are outstanding

Pull block fixes from Jens Axboe:

 - Two small nvme fixes, one is a fabrics connection fix, the other one
   a cleanup made possible by that fix (Anton, via Keith)

 - Fix requeue handling in umb ubd (Anton)

 - Fix spin_lock_irq() nesting in blk-iocost (Dan)

 - Three small io_uring fixes:
     - Install io_uring fd after done with ctx (me)
     - Clear ->result before every poll issue (me)
     - Fix leak of shadow request on error (Pavel)

* tag 'for-linus-20191101' of git://git.kernel.dk/linux-block:
  iocost: don't nest spin_lock_irq in ioc_weight_write()
  io_uring: ensure we clear io_kiocb->result before each issue
  um-ubd: Entrust re-queue to the upper layers
  nvme-multipath: remove unused groups_only mode in ana log
  nvme-multipath: fix possible io hang after ctrl reconnect
  io_uring: don't touch ctx in setup after ring fd install
  io_uring: Fix leaked shadow_req

Pull RISC-V fixes from Paul Walmsley:
 "One fix for PCIe users:

   - Fix legacy PCI I/O port access emulation

  One set of cleanups:

   - Resolve most of the warnings generated by sparse across arch/riscv.
     No functional changes

  And one MAINTAINERS update:

   - Update Palmer's E-mail address"

* tag 'riscv/for-v5.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  MAINTAINERS: Change to my personal email address
  RISC-V: Add PCIe I/O BAR memory mapping
  riscv: for C functions called only from assembly, mark with __visible
  riscv: fp: add missing __user pointer annotations
  riscv: add missing header file includes
  riscv: mark some code and data as file-static
  riscv: init: merge split string literals in preprocessor directive
  riscv: add prototypes for assembly language functions from head.S

Pull parisc fix from Helge Deller:
 "Fix a parisc kernel crash with ftrace functions when compiled without
  frame pointers"

* 'parisc-5.4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: fix frame pointer in ftrace_regs_caller()

Jakub Kicinski says:

====================
fix BPF offload related bugs

test_offload.py catches some recently added bugs.

First of a bug in test_offload.py itself after recent changes
to netdevsim is fixed.

Second patch fixes a bug in cls_bpf, and last one addresses
a problem with the recently added XDP installation optimization.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

When netdevice with offloaded BPF programs is destroyed
the programs are orphaned and removed from the program
IDA - their IDs get released (the programs may remain
accessible via existing open file descriptors and pinned
files). After IDs are released they are set to 0.

This confuses dev_change_xdp_fd() because it compares
the __dev_xdp_query() result where 0 means no program
with prog->aux->id where 0 means orphaned.

dev_change_xdp_fd() would have incorrectly returned success
even though it had not installed the program.

Since drivers already catch this case via bpf_offload_dev_match()
let them handle this case. The error message drivers produce in
this case ("program loaded for a different device") is in fact
correct as the orphaned program must had to be loaded for a
different device.

Fixes: c14a9f63 ("net: Don't call XDP_SETUP_PROG when nothing is changed")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Commit 40119211 ("net: sched: refactor block offloads counter
usage") missed the fact that either new prog or old prog may be
NULL.

Fixes: 40119211 ("net: sched: refactor block offloads counter usage")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

DebugFS for netdevsim now contains some "action trigger" files
which are write only. Don't try to capture the contents of those.

Note that we can't use os.access() because the script requires
root.

Fixes: 4418f862 ("netdevsim: implement support for devlink region and snapshots")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This test reports EINVAL for getsockopt(SOL_SOCKET, SO_DOMAIN)
occasionally due to the uninitialized length parameter.
Initialize it to fix this, and also use int for "test_family" to comply
with the API standard.

Fixes: d6a61f80 ("soreuseport: test mixed v4/v6 sockets")
Reported-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Wei Wang <weiwan@google.com>
Cc: Craig Gallek <cgallek@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

As reported in [0] at least one RTL8168dp version has problems
establishing a link. This chip version has an integrated RTL8211b PHY,
however the chip seems to report a wrong PHY ID, resulting in a wrong
PHY driver (for Generic Realtek PHY) being loaded.
Work around this issue by adding a hook to r8168dp_2_mdio_read()
for returning the correct PHY ID.

[0] https://bbs.archlinux.org/viewtopic.php?id=246508

Fixes: 242cd9b5 ("r8169: use phy_resume/phy_suspend")
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Since it became possible for the DSA core to use a CPU port different
than 8, our bcm_sf2_imp_setup() function was broken because it assumes
that registers are applicable to port 8. In particular, the port's MAC
is going to stay disabled, so make sure we clear the RX_DIS and TX_DIS
bits if we are not configured for port 8.

Fixes: 9f91484f ("net: dsa: make "label" property optional for dsa2")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The phylink_dbg() macro does not follow dynamic debug or defined(DEBUG)
and as a result, it spams the kernel log since a PR_DEBUG level is
currently used. Fix it to be defined appropriately whether
CONFIG_DYNAMIC_DEBUG or defined(DEBUG) are set.

Fixes: 17091180 ("net: phylink: Add phylink_{printk, err, warn, info, dbg} macros")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Synces the DMA buffer properly in order for CPU and device to see
the most up-to-data data.
Signed-off-by: Yangchun Fu <yangchun@google.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Historically linux tried to stick to RFC 791, 1122, 2003
for IPv4 ID field generation.

RFC 6864 made clear that no matter how hard we try,
we can not ensure unicity of IP ID within maximum
lifetime for all datagrams with a given source
address/destination address/protocol tuple.

Linux uses a per socket inet generator (inet_id), initialized
at connection startup with a XOR of 'jiffies' and other
fields that appear clear on the wire.

Thiemo Nagel pointed that this strategy is a privacy
concern as this provides 16 bits of entropy to fingerprint
devices.

Let's switch to a random starting point, this is just as
good as far as RFC 6864 is concerned and does not leak
anything critical.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Thiemo Nagel <tnagel@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Jeff Kirsher says:

====================
Intel Wired LAN Driver Updates 2019-11-01

This series contains updates to e1000, igb, igc, ixgbe, i40e and driver
documentation.

Lyude Paul fixes an issue where a fatal read error occurs when the
device is unplugged from the machine.  So change the read error into a
warn while the device is still present.

Manfred Rudigier found that the i350 device was not apart of the "Media
Auto Sense" feature, yet the device supports it.  So add the missing
i350 device to the check and fix an issue where the media auto sense
would flip/flop when no cable was connected to the port causing spurious
kernel log messages.

I fixed an issue where the fix to resolve receive buffer starvation was
applied in more than one place in the driver, one being the incorrect
location in the i40e driver.

Wenwen Wang fixes a potential memory leak in e1000 where allocated
memory is not properly cleaned up in one of the error paths.

Jonathan Neuschäfer cleans up the driver documentation to be consistent
and remove the footnote reference, since the footnote no longer exists in
the documentation.

Igor Pylypiv cleans up a duplicate clearing of a bit, no need to clear
it twice.

v2: Fixed alignment issue in patch 3 of the series based on community
    feedback.
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Signed-off-by: David S. Miller <davem@davemloft.net>