These are the Foxconn-branded variants of the Dell DW5821e modules,
same USB layout as those. The device exposes AT, NMEA and DIAG ports
in both USB configurations.

P:  Vendor=0489 ProdID=e0b4 Rev=03.18
S:  Manufacturer=FII
S:  Product=T77W968 LTE
S:  SerialNumber=0123456789ABCDEF
C:  #Ifs= 6 Cfg#= 1 Atr=a0 MxPwr=500mA
I:  If#=0x0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=qmi_wwan
I:  If#=0x1 Alt= 0 #EPs= 1 Cls=03(HID  ) Sub=00 Prot=00 Driver=usbhid
I:  If#=0x2 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
I:  If#=0x3 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
I:  If#=0x4 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
I:  If#=0x5 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=option

P:  Vendor=0489 ProdID=e0b4 Rev=03.18
S:  Manufacturer=FII
S:  Product=T77W968 LTE
S:  SerialNumber=0123456789ABCDEF
C:  #Ifs= 7 Cfg#= 2 Atr=a0 MxPwr=500mA
I:  If#=0x0 Alt= 0 #EPs= 1 Cls=02(commc) Sub=0e Prot=00 Driver=cdc_mbim
I:  If#=0x1 Alt= 1 #EPs= 2 Cls=0a(data ) Sub=00 Prot=02 Driver=cdc_mbim
I:  If#=0x2 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
I:  If#=0x3 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
I:  If#=0x4 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
I:  If#=0x5 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=option
I:  If#=0x6 Alt= 0 #EPs= 1 Cls=ff(vend.) Sub=ff Prot=ff Driver=(none)
Signed-off-by: Aleksander Morgado <aleksander@aleksander.es>
[ johan: drop id defines ]
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

Drop the redundant port open flag and corresponding checks. USB serial
core will not call any of these driver callbacks for a closed port, and the
write URBs are stopped at close().
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

Drop read-urb check which is always false from completion the callback.

The driver read-urb pointer is set at every open and is never cleared.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

Drop the custom port driver data accessors and paranoid sanity checks.
The driver data is not cleared until the driver is unbound.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

Drop the helper used to retrieve the serial struct pointer from the port
structure.

Note that this helper was only used when the serial structure was
actually not needed.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

Drop the likewise paranoid serial structure sanity checks.

USB serial core sets the serial pointer in the port structures at
initialisation and it is never cleared, and similar for the serial
structure type.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

Drop the paranoid port structure sanity checks which are confusing at
best.

The driver data port pointer is set at port probe and never cleared,
while USB serial core sets the tty driver data at install and won't call
any driver functions with a NULL port pointer.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

The bulk-in URB context is set to the driver-data struct at open and is
never cleared so drop the redundant check in the completion callback.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

The interrupt handling is completely broken and has in fact never been
been enabled due to an inverted test for an interrupt endpoint in
open() that prevented the interrupt URB from being submitted.

Other highlights include missing interrupt URB resubmission (had it
ever been submitted), missing locking when managing the open-port count,
and NULL-pointer dereferences that could have been triggered by a
malicious device.

Rip out this broken crap which is beyond repair instead of pretending
we support this feature.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

The driver would return success and leave the port structures
half-initialised if any of the register accesses during probe fails.

This would specifically leave the port control urb unallocated,
something which could trigger a NULL pointer dereference on interrupt
events.

Fortunately the interrupt implementation is completely broken and has
never even been enabled...

Note that the zero-length-enable register write used to set the zle-flag
for all ports is moved to attach.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

Document the MCS7810 detection hack which relies on having the GPO and
GPI pins connected as recommended by ASIX.

Note that GPO (pin 42) is really RTS of the third port which will be
toggled for the corresponding physical port on two- and four-port
devices.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

The current device-type detection is fragile and can't really be relied
upon. Instead of sprinkling device-id conditionals throughout the
driver, let's use the device-id table to encode the number of ports and
whether the device has a driver-controlled activity LED (MCS7810).
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

The driver was setting the device remote-wakeup feature during probe in
violation of the USB specification (which says it should only be set
just prior to suspending the device). This could potentially waste
power during suspend as well as lead to spurious wakeups.

Note that USB core would clear the remote-wakeup feature at first
resume.

Fixes: 3f542974 ("USB: Moschip 7840 USB-Serial Driver")
Cc: stable <stable@vger.kernel.org>     # 2.6.19
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

The driver was setting the device remote-wakeup feature during probe in
violation of the USB specification (which says it should only be set
just prior to suspending the device). This could potentially waste
power during suspend as well as lead to spurious wakeups.

Note that USB core would clear the remote-wakeup feature at first
resume.

Fixes: 0f64478c ("USB: add USB serial mos7720 driver")
Cc: stable <stable@vger.kernel.org>     # 2.6.19
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

The device exposes AT, NMEA and DIAG ports in both USB configurations.
Exactly same layout as the default DW5821e module, just a different
vid/pid.

P:  Vendor=413c ProdID=81e0 Rev=03.18
S:  Manufacturer=Dell Inc.
S:  Product=DW5821e-eSIM Snapdragon X20 LTE
S:  SerialNumber=0123456789ABCDEF
C:  #Ifs= 6 Cfg#= 1 Atr=a0 MxPwr=500mA
I:  If#=0x0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=qmi_wwan
I:  If#=0x1 Alt= 0 #EPs= 1 Cls=03(HID  ) Sub=00 Prot=00 Driver=usbhid
I:  If#=0x2 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
I:  If#=0x3 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
I:  If#=0x4 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
I:  If#=0x5 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=option

P:  Vendor=413c ProdID=81e0 Rev=03.18
S:  Manufacturer=Dell Inc.
S:  Product=DW5821e-eSIM Snapdragon X20 LTE
S:  SerialNumber=0123456789ABCDEF
C:  #Ifs= 7 Cfg#= 2 Atr=a0 MxPwr=500mA
I:  If#=0x0 Alt= 0 #EPs= 1 Cls=02(commc) Sub=0e Prot=00 Driver=cdc_mbim
I:  If#=0x1 Alt= 1 #EPs= 2 Cls=0a(data ) Sub=00 Prot=02 Driver=cdc_mbim
I:  If#=0x2 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
I:  If#=0x3 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
I:  If#=0x4 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
I:  If#=0x5 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=option
I:  If#=0x6 Alt= 0 #EPs= 1 Cls=ff(vend.) Sub=ff Prot=ff Driver=(none)
Signed-off-by: Aleksander Morgado <aleksander@aleksander.es>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

Add USB ID for MOXA UPort 2210. This device contains mos7820 but
it passes GPIO0 check implemented by driver and it's detected as
mos7840. Hence product id check is added to force mos7820 mode.
Signed-off-by: Pavel Löbl <pavel@loebl.cz>
Cc: stable <stable@vger.kernel.org>
[ johan: rename id defines and add vendor-id check ]
Signed-off-by: Johan Hovold <johan@kernel.org>

The current ch341 divisor algorithm was known to give inaccurate results
for certain higher line speeds. Jonathan Olds <jontio@i4free.co.nz>
investigated this, determined the basic equations used to derive the
divisors and confirmed them experimentally [1].

The equations Jonathan used could be generalised further to:

	baudrate = 48000000 / (2^(12 - 3 * ps - fact) * div), where

		0 <= ps <= 3,
		0 <= fact <= 1,
		2 <= div <= 256 if fact = 0, or
		9 <= div <= 256 if fact = 1

which will also give better results for lower rates.

Notably the error is reduced for the following standard rates:

	1152000	(4.0% instead of 15% error)
	 921600	(0.16% instead of -7.5% error)
	 576000	(-0.80% instead of -5.6% error)
	    200	(0.16% instead of -0.69% error)
	    134	(-0.05% instead of -0.63% error)
	    110	(0.03% instead of -0.44% error)

but also for many non-standard ones.

The current algorithm also suffered from rounding issues (e.g.
requesting 2950000 Bd resulted in a rate of 2 MBd instead of 3 MBd and
thus a -32% instead of 1.7% error).

The new algorithm was inspired by the current vendor driver even if that
one only handles two higher rates that require fact=1 by hard coding the
corresponding divisors [2].

Michael Dreher <michael@5dot1.de> also did a similar generalisation of
Jonathan's work and has published his results with a very good summary
that provides further insights into how this device works [3].

[1] https://lkml.kernel.org/r/000001d51f34$bad6afd0$30840f70$@co.nz
[2] http://www.wch.cn/download/CH341SER_LINUX_ZIP.html
[3] https://github.com/nospam2000/ch341-baudrate-calculationReported-by: Jonathan Olds <jontio@i4free.co.nz>
Tested-by: Jonathan Olds <jontio@i4free.co.nz>
Cc: Michael Dreher <michael@5dot1.de>
Signed-off-by: Johan Hovold <johan@kernel.org>

Prolific has developed a new USB to UART chip: PL2303HXN
PL2303HXN : PL2303GC/PL2303GS/PL2303GT/PL2303GL/PL2303GE/PL2303GB
The Vendor request used by the PL2303HXN (TYPE_HXN) is different from
the existing PL2303 series (TYPE_HX & TYPE_01).
Therefore, different Vendor requests are used to issue related commands.

1. Added a new TYPE_HXN type in pl2303_type_data, and then executes
   new Vendor request,new flow control and other related instructions
   if TYPE_HXN is recognized.

2. Because the new PL2303HXN only accept the new Vendor request,
   the old Vendor request cannot be accepted (the error message
   will be returned)
   So first determine the TYPE_HX or TYPE_HXN through
   PL2303_READ_TYPE_HX_STATUS in pl2303_startup.

  2.1 If the return message is "1", then the PL2303 is the existing
      TYPE_HX/ TYPE_01 series.
      The other settings in pl2303_startup are to continue execution.
  2.2 If the return message is "not 1", then the PL2303 is the new
      TYPE_HXN series.
      The other settings in pl2303_startup are ignored.
      (PL2303HXN will directly use the default value in the hardware,
       no need to add additional settings through the software)

3. In pl2303_open: Because TYPE_HXN is different from the instruction of reset
   down/up stream used by TYPE_HX.
   Therefore, we will also execute different instructions here.

4. In pl2303_set_termios: The UART flow control instructions used by
   TYPE_HXN/TYPE_HX/TYPE_01 are different.
   Therefore, we will also execute different instructions here.

5. In pl2303_vendor_read & pl2303_vendor_write, since TYPE_HXN is different
   from the vendor request instruction used by TYPE_HX/TYPE_01,
   it will also execute different instructions here.

6. In pl2303_update_reg: TYPE_HXN used different register for flow control.
   Therefore, we will also execute different instructions here.
Signed-off-by: Charles Yeh <charlesyeh522@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>

Pull tracing fixes from Steven Rostedt:
 "A few tracing fixes:

   - Remove lockdown from tracefs itself and moved it to the trace
     directory. Have the open functions there do the lockdown checks.

   - Fix a few races with opening an instance file and the instance
     being deleted (Discovered during the lockdown updates). Kept
     separate from the clean up code such that they can be backported to
     stable easier.

   - Clean up and consolidated the checks done when opening a trace
     file, as there were multiple checks that need to be done, and it
     did not make sense having them done in each open instance.

   - Fix a regression in the record mcount code.

   - Small hw_lat detector tracer fixes.

   - A trace_pipe read fix due to not initializing trace_seq"

* tag 'trace-v5.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Initialize iter->seq after zeroing in tracing_read_pipe()
  tracing/hwlat: Don't ignore outer-loop duration when calculating max_latency
  tracing/hwlat: Report total time spent in all NMIs during the sample
  recordmcount: Fix nop_mcount() function
  tracing: Do not create tracefs files if tracefs lockdown is in effect
  tracing: Add locked_down checks to the open calls of files created for tracefs
  tracing: Add tracing_check_open_get_tr()
  tracing: Have trace events system open call tracing_open_generic_tr()
  tracing: Get trace_array reference for available_tracers files
  ftrace: Get a reference counter for the trace_array on filter files
  tracefs: Revert ccbd54ff ("tracefs: Restrict tracefs when the kernel is locked down")

Merge tag 'hwmon-for-v5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fixes from Guenter Roeck:

 - Update/fix inspur-ipsps1 and k10temp Documentation

 - Fix nct7904 driver

 - Fix HWMON_P_MIN_ALARM mask in hwmon core

* tag 'hwmon-for-v5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: docs: Extend inspur-ipsps1 title underline
  hwmon: (nct7904) Add array fan_alarm and vsen_alarm to store the alarms in nct7904_data struct.
  docs: hwmon: Include 'inspur-ipsps1.rst' into docs
  hwmon: Fix HWMON_P_MIN_ALARM mask
  hwmon: (k10temp) Update documentation and add temp2_input info
  hwmon: (nct7904) Fix the incorrect value of vsen_mask in nct7904_data struct

Pull MTD fixes from Richard Weinberger:
 "Two fixes for MTD:

   - spi-nor: Fix for a regression in write_sr()

   - rawnand: Regression fix for the au1550nd driver"

* tag 'fixes-for-5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux:
  mtd: rawnand: au1550nd: Fix au_read_buf16() prototype
  mtd: spi-nor: Fix direction of the write_sr() transfer

Pull io_uring fix from Jens Axboe:
 "Single small fix for a regression in the sequence logic for linked
  commands"

* tag 'for-linus-20191012' of git://git.kernel.dk/linux-block:
  io_uring: fix sequence logic for timeout requests

A customer reported the following softlockup:

[899688.160002] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [test.sh:16464]
[899688.160002] CPU: 0 PID: 16464 Comm: test.sh Not tainted 4.12.14-6.23-azure #1 SLE12-SP4
[899688.160002] RIP: 0010:up_write+0x1a/0x30
[899688.160002] Kernel panic - not syncing: softlockup: hung tasks
[899688.160002] RIP: 0010:up_write+0x1a/0x30
[899688.160002] RSP: 0018:ffffa86784d4fde8 EFLAGS: 00000257 ORIG_RAX: ffffffffffffff12
[899688.160002] RAX: ffffffff970fea00 RBX: 0000000000000001 RCX: 0000000000000000
[899688.160002] RDX: ffffffff00000001 RSI: 0000000000000080 RDI: ffffffff970fea00
[899688.160002] RBP: ffffffffffffffff R08: ffffffffffffffff R09: 0000000000000000
[899688.160002] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8b59014720d8
[899688.160002] R13: ffff8b59014720c0 R14: ffff8b5901471090 R15: ffff8b5901470000
[899688.160002]  tracing_read_pipe+0x336/0x3c0
[899688.160002]  __vfs_read+0x26/0x140
[899688.160002]  vfs_read+0x87/0x130
[899688.160002]  SyS_read+0x42/0x90
[899688.160002]  do_syscall_64+0x74/0x160

It caught the process in the middle of trace_access_unlock(). There is
no loop. So, it must be looping in the caller tracing_read_pipe()
via the "waitagain" label.

Crashdump analyze uncovered that iter->seq was completely zeroed
at this point, including iter->seq.seq.size. It means that
print_trace_line() was never able to print anything and
there was no forward progress.

The culprit seems to be in the code:

	/* reset all but tr, trace, and overruns */
	memset(&iter->seq, 0,
	       sizeof(struct trace_iterator) -
	       offsetof(struct trace_iterator, seq));

It was added by the commit 53d0aa77 ("ftrace:
add logic to record overruns"). It was v2.6.27-rc1.
It was the time when iter->seq looked like:

     struct trace_seq {
	unsigned char		buffer[PAGE_SIZE];
	unsigned int		len;
     };

There was no "size" variable and zeroing was perfectly fine.

The solution is to reinitialize the structure after or without
zeroing.

Link: http://lkml.kernel.org/r/20191011142134.11997-1-pmladek@suse.comSigned-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

max_latency is intended to record the maximum ever observed hardware
latency, which may occur in either part of the loop (inner/outer). So
we need to also consider the outer-loop sample when updating
max_latency.

Link: http://lkml.kernel.org/r/157073345463.17189.18124025522664682811.stgit@srivatsa-ubuntu

Fixes: e7c15cd8 ("tracing: Added hardware latency tracer")
Cc: stable@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

nmi_total_ts is supposed to record the total time spent in *all* NMIs
that occur on the given CPU during the (active portion of the)
sampling window. However, the code seems to be overwriting this
variable for each NMI, thereby only recording the time spent in the
most recent NMI. Fix it by accumulating the duration instead.

Link: http://lkml.kernel.org/r/157073343544.17189.13911783866738671133.stgit@srivatsa-ubuntu

Fixes: 7b2c8625 ("tracing: Add NMI tracing in hwlat detector")
Cc: stable@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

The removal of the longjmp code in recordmcount.c mistakenly made the return
of make_nop() being negative an exit of nop_mcount(). It should not exit the
routine, but instead just not process that part of the code. By exiting with
an error code, it would cause the update of recordmcount to fail some files
which would fail the build if ftrace function tracing was enabled.

Link: http://lkml.kernel.org/r/20191009110538.5909fec6@gandalf.local.homeReported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Fixes: 3f1df120 ("recordmcount: Rewrite error/success handling")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

If on boot up, lockdown is activated for tracefs, don't even bother creating
the files. This can also prevent instances from being created if lockdown is
in effect.

Link: http://lkml.kernel.org/r/CAHk-=whC6Ji=fWnjh2+eS4b15TnbsS4VPVtvBOwCy1jjEG_JHQ@mail.gmail.comSuggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Added various checks on open tracefs calls to see if tracefs is in lockdown
mode, and if so, to return -EPERM.

Note, the event format files (which are basically standard on all machines)
as well as the enabled_functions file (which shows what is currently being
traced) are not lockde down. Perhaps they should be, but it seems counter
intuitive to lockdown information to help you know if the system has been
modified.

Link: http://lkml.kernel.org/r/CAHk-=wj7fGPKUspr579Cii-w_y60PtRaiDgKuxVtBAMK0VNNkA@mail.gmail.comSuggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Currently, most files in the tracefs directory test if tracing_disabled is
set. If so, it should return -ENODEV. The tracing_disabled is called when
tracing is found to be broken. Originally it was done in case the ring
buffer was found to be corrupted, and we wanted to prevent reading it from
crashing the kernel. But it's also called if a tracing selftest fails on
boot. It's a one way switch. That is, once it is triggered, tracing is
disabled until reboot.

As most tracefs files can also be used by instances in the tracefs
directory, they need to be carefully done. Each instance has a trace_array
associated to it, and when the instance is removed, the trace_array is
freed. But if an instance is opened with a reference to the trace_array,
then it requires looking up the trace_array to get its ref counter (as there
could be a race with it being deleted and the open itself). Once it is
found, a reference is added to prevent the instance from being removed (and
the trace_array associated with it freed).

Combine the two checks (tracing_disabled and trace_array_get()) into a
single helper function. This will also make it easier to add lockdown to
tracefs later.

Link: http://lkml.kernel.org/r/20191011135458.7399da44@gandalf.local.homeSigned-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Instead of having the trace events system open call open code the taking of
the trace_array descriptor (with trace_array_get()) and then calling
trace_open_generic(), have it use the tracing_open_generic_tr() that does
the combination of the two. This requires making tracing_open_generic_tr()
global.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

As instances may have different tracers available, we need to look at the
trace_array descriptor that shows the list of the available tracers for the
instance. But there's a race between opening the file and an admin
deleting the instance. The trace_array_get() needs to be called before
accessing the trace_array.

Cc: stable@vger.kernel.org
Fixes: 607e2ea1 ("tracing: Set up infrastructure to allow tracers for instances")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

The ftrace set_ftrace_filter and set_ftrace_notrace files are specific for
an instance now. They need to take a reference to the instance otherwise
there could be a race between accessing the files and deleting the instance.

It wasn't until the :mod: caching where these file operations started
referencing the trace_array directly.

Cc: stable@vger.kernel.org
Fixes: 673feb9d ("ftrace: Add :mod: caching infrastructure to trace_array")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Running the latest kernel through my "make instances" stress tests, I
triggered the following bug (with KASAN and kmemleak enabled):

mkdir invoked oom-killer:
gfp_mask=0x40cd0(GFP_KERNEL|__GFP_COMP|__GFP_RECLAIMABLE), order=0,
oom_score_adj=0
CPU: 1 PID: 2229 Comm: mkdir Not tainted 5.4.0-rc2-test #325
Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014
Call Trace:
 dump_stack+0x64/0x8c
 dump_header+0x43/0x3b7
 ? trace_hardirqs_on+0x48/0x4a
 oom_kill_process+0x68/0x2d5
 out_of_memory+0x2aa/0x2d0
 __alloc_pages_nodemask+0x96d/0xb67
 __alloc_pages_node+0x19/0x1e
 alloc_slab_page+0x17/0x45
 new_slab+0xd0/0x234
 ___slab_alloc.constprop.86+0x18f/0x336
 ? alloc_inode+0x2c/0x74
 ? irq_trace+0x12/0x1e
 ? tracer_hardirqs_off+0x1d/0xd7
 ? __slab_alloc.constprop.85+0x21/0x53
 __slab_alloc.constprop.85+0x31/0x53
 ? __slab_alloc.constprop.85+0x31/0x53
 ? alloc_inode+0x2c/0x74
 kmem_cache_alloc+0x50/0x179
 ? alloc_inode+0x2c/0x74
 alloc_inode+0x2c/0x74
 new_inode_pseudo+0xf/0x48
 new_inode+0x15/0x25
 tracefs_get_inode+0x23/0x7c
 ? lookup_one_len+0x54/0x6c
 tracefs_create_file+0x53/0x11d
 trace_create_file+0x15/0x33
 event_create_dir+0x2a3/0x34b
 __trace_add_new_event+0x1c/0x26
 event_trace_add_tracer+0x56/0x86
 trace_array_create+0x13e/0x1e1
 instance_mkdir+0x8/0x17
 tracefs_syscall_mkdir+0x39/0x50
 ? get_dname+0x31/0x31
 vfs_mkdir+0x78/0xa3
 do_mkdirat+0x71/0xb0
 sys_mkdir+0x19/0x1b
 do_fast_syscall_32+0xb0/0xed

I bisected this down to the addition of the proxy_ops into tracefs for
lockdown. It appears that the allocation of the proxy_ops and then freeing
it in the destroy_inode callback, is causing havoc with the memory system.
Reading the documentation about destroy_inode and talking with Linus about
this, this is buggy and wrong. When defining the destroy_inode() method, it
is expected that the destroy_inode() will also free the inode, and not just
the extra allocations done in the creation of the inode. The faulty commit
causes a memory leak of the inode data structure when they are deleted.

Instead of allocating the proxy_ops (and then having to free it) the checks
should be done by the open functions themselves, and not hack into the
tracefs directory. First revert the tracefs updates for locked_down and then
later we can add the locked_down checks in the kernel/trace files.

Link: http://lkml.kernel.org/r/20191011135458.7399da44@gandalf.local.home

Fixes: ccbd54ff ("tracefs: Restrict tracefs when the kernel is locked down")
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull char/misc driver fixes from Greg KH:
 "Here are some small char/misc driver fixes for 5.4-rc3.

  Nothing huge here. Some binder driver fixes (although it is still
  being discussed if these all fix the reported issues or not, so more
  might be coming later), some mei device ids and fixes, and a google
  firmware driver bugfix that fixes a regression, as well as some other
  tiny fixes.

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

* tag 'char-misc-5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  firmware: google: increment VPD key_len properly
  w1: ds250x: Fix build error without CRC16
  virt: vbox: fix memory leak in hgcm_call_preprocess_linaddr
  binder: Fix comment headers on binder_alloc_prepare_to_free()
  binder: prevent UAF read in print_binder_transaction_log_entry()
  misc: fastrpc: prevent memory leak in fastrpc_dma_buf_attach
  mei: avoid FW version request on Ibex Peak and earlier
  mei: me: add comet point (lake) LP device ids

Pull staging/IIO driver fixes from Greg KH:
 "Here are some staging and IIO driver fixes for 5.4-rc3.

  The "biggest" thing here is a removal of the fbtft device and flexfb
  code as they have been abandoned by their authors and are no longer
  needed for that hardware.

  Other than that, the usual amount of staging driver and iio driver
  fixes for reported issues, and some speakup sysfs file documentation,
  which has been long awaited for.

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

* tag 'staging-5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (32 commits)
  iio: Fix an undefied reference error in noa1305_probe
  iio: light: opt3001: fix mutex unlock race
  iio: adc: ad799x: fix probe error handling
  iio: light: add missing vcnl4040 of_compatible
  iio: light: fix vcnl4000 devicetree hooks
  iio: imu: st_lsm6dsx: fix waitime for st_lsm6dsx i2c controller
  iio: adc: axp288: Override TS pin bias current for some models
  iio: imu: adis16400: fix memory leak
  iio: imu: adis16400: release allocated memory on failure
  iio: adc: stm32-adc: fix a race when using several adcs with dma and irq
  iio: adc: stm32-adc: move registers definitions
  iio: accel: adxl372: Perform a reset at start up
  iio: accel: adxl372: Fix push to buffers lost samples
  iio: accel: adxl372: Fix/remove limitation for FIFO samples
  iio: adc: hx711: fix bug in sampling of data
  staging: vt6655: Fix memory leak in vt6655_probe
  staging: exfat: Use kvzalloc() instead of kzalloc() for exfat_sb_info
  Staging: fbtft: fix memory leak in fbtft_framebuffer_alloc
  staging: speakup: document sysfs attributes
  staging: rtl8188eu: fix HighestRate check in odm_ARFBRefresh_8188E()
  ...

Pull tty/serial driver fixes from Greg KH:
 "Here are some small tty and serial driver fixes for 5.4-rc3 that
  resolve a number of reported issues and regressions.

  None of these are huge, full details are in the shortlog. There's also
  a MAINTAINERS update that I think you might have already taken in your
  tree already, but git should handle that merge easily.

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

* tag 'tty-5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  MAINTAINERS: kgdb: Add myself as a reviewer for kgdb/kdb
  tty: serial: imx: Use platform_get_irq_optional() for optional IRQs
  serial: fix kernel-doc warning in comments
  serial: 8250_omap: Fix gpio check for auto RTS/CTS
  serial: mctrl_gpio: Check for NULL pointer
  tty: serial: fsl_lpuart: Fix lpuart_flush_buffer()
  tty: serial: Fix PORT_LINFLEXUART definition
  tty: n_hdlc: fix build on SPARC
  serial: uartps: Fix uartps_major handling
  serial: uartlite: fix exit path null pointer
  tty: serial: linflexuart: Fix magic SysRq handling
  serial: sh-sci: Use platform_get_irq_optional() for optional interrupts
  dt-bindings: serial: sh-sci: Document r8a774b1 bindings
  serial/sifive: select SERIAL_EARLYCON
  tty: serial: rda: Fix the link time qualifier of 'rda_uart_exit()'
  tty: serial: owl: Fix the link time qualifier of 'owl_uart_exit()'

Pull USB fixes from Greg KH:
 "Here are a lot of small USB driver fixes for 5.4-rc3.

  syzbot has stepped up its testing of the USB driver stack, now able to
  trigger fun race conditions between disconnect and probe functions.
  Because of that we have a lot of fixes in here from Johan and others
  fixing these reported issues that have been around since almost all
  time.

  We also are just deleting the rio500 driver, making all of the syzbot
  bugs found in it moot as it turns out no one has been using it for
  years as there is a userspace version that is being used instead.

  There are also a number of other small fixes in here, all resolving
  reported issues or regressions.

  All have been in linux-next without any reported issues"

* tag 'usb-5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (65 commits)
  USB: yurex: fix NULL-derefs on disconnect
  USB: iowarrior: use pr_err()
  USB: iowarrior: drop redundant iowarrior mutex
  USB: iowarrior: drop redundant disconnect mutex
  USB: iowarrior: fix use-after-free after driver unbind
  USB: iowarrior: fix use-after-free on release
  USB: iowarrior: fix use-after-free on disconnect
  USB: chaoskey: fix use-after-free on release
  USB: adutux: fix use-after-free on release
  USB: ldusb: fix NULL-derefs on driver unbind
  USB: legousbtower: fix use-after-free on release
  usb: cdns3: Fix for incorrect DMA mask.
  usb: cdns3: fix cdns3_core_init_role()
  usb: cdns3: gadget: Fix full-speed mode
  USB: usb-skeleton: drop redundant in-urb check
  USB: usb-skeleton: fix use-after-free after driver unbind
  USB: usb-skeleton: fix NULL-deref on disconnect
  usb:cdns3: Fix for CV CH9 running with g_zero driver.
  usb: dwc3: Remove dev_err() on platform_get_irq() failure
  usb: dwc3: Switch to platform_get_irq_byname_optional()
  ...

Pull scheduler fixes from Ingo Molnar:
 "Two fixes: a guest-cputime accounting fix, and a cgroup bandwidth
  quota precision fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/vtime: Fix guest/system mis-accounting on task switch
  sched/fair: Scale bandwidth quota and period without losing quota/period ratio precision

Pull perf fixes from Ingo Molnar:
 "Mostly tooling fixes, but also a couple of updates for new Intel
  models (which are technically hw-enablement, but to users it's a fix
  to perf behavior on those new CPUs - hope this is fine), an AUX
  inheritance fix, event time-sharing fix, and a fix for lost non-perf
  NMI events on AMD systems"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
  perf/x86/cstate: Add Tiger Lake CPU support
  perf/x86/msr: Add Tiger Lake CPU support
  perf/x86/intel: Add Tiger Lake CPU support
  perf/x86/cstate: Update C-state counters for Ice Lake
  perf/x86/msr: Add new CPU model numbers for Ice Lake
  perf/x86/cstate: Add Comet Lake CPU support
  perf/x86/msr: Add Comet Lake CPU support
  perf/x86/intel: Add Comet Lake CPU support
  perf/x86/amd: Change/fix NMI latency mitigation to use a timestamp
  perf/core: Fix corner case in perf_rotate_context()
  perf/core: Rework memory accounting in perf_mmap()
  perf/core: Fix inheritance of aux_output groups
  perf annotate: Don't return -1 for error when doing BPF disassembly
  perf annotate: Return appropriate error code for allocation failures
  perf annotate: Fix arch specific ->init() failure errors
  perf annotate: Propagate the symbol__annotate() error return
  perf annotate: Fix the signedness of failure returns
  perf annotate: Propagate perf_env__arch() error
  perf evsel: Fall back to global 'perf_env' in perf_evsel__env()
  perf tools: Propagate get_cpuid() error
  ...