A Root Complex Event Collector terminates error and PME messages from
associated RCiEPs.

Use the RCEC Endpoint Association Extended Capability to identify
associated RCiEPs. Link the associated RCiEPs as the RCECs are enumerated.
Co-developed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Link: https://lore.kernel.org/r/20201121001036.8560-12-sean.v.kelley@intel.com
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # non-native/no RCEC
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

A Root Complex Event Collector (RCEC) collects and signals AER errors that
were detected by Root Complex Integrated Endpoints (RCiEPs), but it may
also signal errors it detects itself.  This is analogous to errors detected
and signaled by a Root Port.

Update the AER service driver to claim RCECs in addition to Root Ports.
Add support for handling RCEC-detected AER errors.  This does not
include handling RCiEP-detected errors that are signaled by the RCEC.

Note that we expect these errors only from the native AER and APEI paths,
not from DPC or EDR.

[bhelgaas: split from combined RCEC/RCiEP patch, commit log]
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

In some cases a bridge may not exist as the hardware controlling may be
handled only by firmware and so is not visible to the OS. This scenario is
also possible in future use cases involving non-native use of RCECs by
firmware. In this scenario, we expect the platform to retain control of the
bridge and to clear error status itself.

Clear error status only when the OS has native control of AER.
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Consolidate subordinate bus checks with pci_walk_bus() into
pci_walk_bridge() for walking below potentially AER affected bridges.

Link: https://lore.kernel.org/r/20201121001036.8560-10-sean.v.kelley@intel.com
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # non-native/no RCEC
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Reverse the sense of the Root Port/Downstream Port conditional for clarity.
No functional change intended.

Link: https://lore.kernel.org/r/20201121001036.8560-9-sean.v.kelley@intel.com
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # non-native/no RCEC
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

pcie_do_recovery() may be called with "dev" being either a bridge (Root
Port or Switch Downstream Port) or an Endpoint.  The bulk of the function
deals with the bridge, so if we start with an Endpoint, we reset "dev" to
be the bridge leading to it.

For clarity, replace "dev" in the body of the function with "bridge".  No
functional change intended.

Link: https://lore.kernel.org/r/20201121001036.8560-8-sean.v.kelley@intel.com
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # non-native/no RCEC
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Instead of calling pci_pcie_type(dev) twice, call it once and save the
result.  No functional change intended.

Link: https://lore.kernel.org/r/20201121001036.8560-7-sean.v.kelley@intel.com
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # non-native/no RCEC
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Use pci_upstream_bridge() in place of dev->bus->self.  No functional change
intended.

Link: https://lore.kernel.org/r/20201121001036.8560-6-sean.v.kelley@intel.com
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # non-native/no RCEC
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

reset_link() appears to be misnamed.  The point is to reset any devices
below a given bridge, so rename it to reset_subordinates() to make it clear
that we are passing a bridge with the intent to reset the devices below it.

Link: https://lore.kernel.org/r/20201121001036.8560-5-sean.v.kelley@intel.com
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # non-native/no RCEC
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Extend support for Root Complex Event Collectors by decoding and caching
the RCEC Endpoint Association Extended Capabilities when enumerating. Use
that cached information for later error source reporting. See PCIe r5.0,
sec 7.9.10.
Co-developed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Link: https://lore.kernel.org/r/20201121001036.8560-4-sean.v.kelley@intel.com
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # non-native/no RCEC
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

If a Root Complex Integrated Endpoint (RCiEP) is implemented, it may signal
errors through a Root Complex Event Collector (RCEC).  Each RCiEP must be
associated with no more than one RCEC.

For an RCEC (which is technically not a Bridge), error messages "received"
from associated RCiEPs must be enabled for "transmission" in order to cause
a System Error via the Root Control register or (when the Advanced Error
Reporting Capability is present) reporting via the Root Error Command
register and logging in the Root Error Status register and Error Source
Identification register.

Given the commonality with Root Ports and the need to also support AER and
PME services for RCECs, extend the Root Port driver to support RCEC devices
by adding the RCEC Class ID to the driver structure.
Co-developed-by: Sean V Kelley <sean.v.kelley@intel.com>
Link: https://lore.kernel.org/r/20201121001036.8560-3-sean.v.kelley@intel.com
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # non-native/no RCEC
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

If an OS has not been granted AER control via _OSC, it should not make
changes to PCI_ERR_ROOT_COMMAND and PCI_ERR_ROOT_STATUS related registers.
Per section 4.5.1 of the System Firmware Intermediary (SFI) _OSC and DPC
Updates ECN [1], this bit also covers these aspects of the PCI Express
Advanced Error Reporting. Based on the above and earlier discussion [2],
make the following changes:

Add a check for the native case (i.e., AER control via _OSC)

Note that the previous "clear, reset, enable" order suggests that the reset
might cause errors that we should ignore. After this commit, those errors
(if any) will remain logged in the PCI_ERR_ROOT_STATUS register.

[1] System Firmware Intermediary (SFI) _OSC and DPC Updates ECN, Feb 24,
    2020, affecting PCI Firmware Specification, Rev. 3.2
    https://members.pcisig.com/wg/PCI-SIG/document/14076
[2] https://lore.kernel.org/linux-pci/20201020162820.GA370938@bjorn-Precision-5520/

Link: https://lore.kernel.org/r/20201121001036.8560-2-sean.v.kelley@intel.com
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # non-native/no RCEC
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Merge tag 'driver-core-5.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core documentation fixes from Greg KH:
 "Some small Documentation fixes that were fallout from the larger
  documentation update we did in 5.10-rc2.

  Nothing major here at all, but all of these have been in linux-next
  and resolve build warnings when building the documentation files"

* tag 'driver-core-5.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  Documentation: remove mic/index from misc-devices/index.rst
  scripts: get_api.pl: Add sub-titles to ABI output
  scripts: get_abi.pl: Don't let ABI files to create subtitles
  docs: leds: index.rst: add a missing file
  docs: ABI: sysfs-class-net: fix a typo
  docs: ABI: sysfs-driver-dma-ioatdma: what starts with /sys

Pull tty/serial fixes from Greg KH:
 "Here are a small number of small tty and serial fixes for some
  reported problems for the tty core, vt code, and some serial drivers.

  They include fixes for:

   - a buggy and obsolete vt font ioctl removal

   - 8250_mtk serial baudrate runtime warnings

   - imx serial earlycon build configuration fix

   - txx9 serial driver error path cleanup issues

   - tty core fix in release_tty that can be triggered by trying to bind
     an invalid serial port name to a speakup console device

  Almost all of these have been in linux-next without any problems, the
  only one that hasn't, just deletes code :)"

* tag 'tty-5.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  vt: Disable KD_FONT_OP_COPY
  tty: fix crash in release_tty if tty->port is not set
  serial: txx9: add missing platform_driver_unregister() on error in serial_txx9_init
  tty: serial: imx: enable earlycon by default if IMX_SERIAL_CONSOLE is enabled
  serial: 8250_mtk: Fix uart_get_baud_rate warning

Pull USB fixes from Greg KH:
 "Here are some small USB fixes and new device ids:

   - USB gadget fixes for some reported issues

   - Fixes for the ever-troublesome apple fastcharge driver, hopefully
     we finally have it right.

   - More USB core quirks for odd devices

   - USB serial driver fixes for some long-standing issues that were
     recently found

   - some new USB serial driver device ids

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

* tag 'usb-5.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  USB: apple-mfi-fastcharge: fix reference leak in apple_mfi_fc_set_property
  usb: mtu3: fix panic in mtu3_gadget_stop()
  USB: serial: option: add Telit FN980 composition 0x1055
  USB: serial: option: add LE910Cx compositions 0x1203, 0x1230, 0x1231
  USB: serial: cyberjack: fix write-URB completion race
  USB: Add NO_LPM quirk for Kingston flash drive
  USB: serial: option: add Quectel EC200T module support
  usb: raw-gadget: fix memory leak in gadget_setup
  usb: dwc2: Avoid leaving the error_debugfs label unused
  usb: dwc3: ep0: Fix delay status handling
  usb: gadget: fsl: fix null pointer checking
  usb: gadget: goku_udc: fix potential crashes in probe
  usb: dwc3: pci: add support for the Intel Alder Lake-S

current->group_leader->exit_signal may change during copy_process() if
current->real_parent exits.

Move the assignment inside tasklist_lock to avoid the race.
Signed-off-by: Eddy Wu <eddy_wu@trendmicro.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

It's buggy:

On Fri, Nov 06, 2020 at 10:30:08PM +0800, Minh Yuan wrote:
> We recently discovered a slab-out-of-bounds read in fbcon in the latest
> kernel ( v5.10-rc2 for now ).  The root cause of this vulnerability is that
> "fbcon_do_set_font" did not handle "vc->vc_font.data" and
> "vc->vc_font.height" correctly, and the patch
> <https://lkml.org/lkml/2020/9/27/223> for VT_RESIZEX can't handle this
> issue.
>
> Specifically, we use KD_FONT_OP_SET to set a small font.data for tty6, and
> use  KD_FONT_OP_SET again to set a large font.height for tty1. After that,
> we use KD_FONT_OP_COPY to assign tty6's vc_font.data to tty1's vc_font.data
> in "fbcon_do_set_font", while tty1 retains the original larger
> height. Obviously, this will cause an out-of-bounds read, because we can
> access a smaller vc_font.data with a larger vc_font.height.

Further there was only one user ever.
- Android's loadfont, busybox and console-tools only ever use OP_GET
  and OP_SET
- fbset documentation only mentions the kernel cmdline font: option,
  not anything else.
- systemd used OP_COPY before release 232 published in Nov 2016

Now unfortunately the crucial report seems to have gone down with
gmane, and the commit message doesn't say much. But the pull request
hints at OP_COPY being broken

https://github.com/systemd/systemd/pull/3651

So in other words, this never worked, and the only project which
foolishly every tried to use it, realized that rather quickly too.

Instead of trying to fix security issues here on dead code by adding
missing checks, fix the entire thing by removing the functionality.

Note that systemd code using the OP_COPY function ignored the return
value, so it doesn't matter what we're doing here really - just in
case a lone server somewhere happens to be extremely unlucky and
running an affected old version of systemd. The relevant code from
font_copy_to_all_vcs() in systemd was:

	/* copy font from active VT, where the font was uploaded to */
	cfo.op = KD_FONT_OP_COPY;
	cfo.height = vcs.v_active-1; /* tty1 == index 0 */
	(void) ioctl(vcfd, KDFONTOP, &cfo);

Note this just disables the ioctl, garbage collecting the now unused
callbacks is left for -next.

v2: Tetsuo found the old mail, which allowed me to find it on another
archive. Add the link too.
Acked-by: Peilin Ye <yepeilin.cs@gmail.com>
Reported-by: Minh Yuan <yuanmingbuaa@gmail.com>
References: https://lists.freedesktop.org/archives/systemd-devel/2016-June/036935.html
References: https://github.com/systemd/systemd/pull/3651
Cc: Greg KH <greg@kroah.com>
Cc: Peilin Ye <yepeilin.cs@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://lore.kernel.org/r/20201108153806.3140315-1-daniel.vetter@ffwll.chSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull xfs fixes from Darrick Wong:

 - Fix an uninitialized struct problem

 - Fix an iomap problem zeroing unwritten EOF blocks

 - Fix some clumsy error handling when writeback fails on filesystems
   with blocksize < pagesize

 - Fix a retry loop not resetting loop variables properly

 - Fix scrub flagging rtinherit inodes on a non-rt fs, since the kernel
   actually does permit that combination

 - Fix excessive page cache flushing when unsharing part of a file

* tag 'xfs-5.10-fixes-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: only flush the unshared range in xfs_reflink_unshare
  xfs: fix scrub flagging rtinherit even if there is no rt device
  xfs: fix missing CoW blocks writeback conversion retry
  iomap: clean up writeback state logic on writepage error
  iomap: support partial page discard on writeback block mapping failure
  xfs: flush new eof page on truncate to avoid post-eof corruption
  xfs: set xefi_discard when creating a deferred agfl free log intent item

Merge procfs splice read fixes from Christoph Hellwig:
 "Greg reported a problem due to the fact that Android tests use procfs
  files to test splice, which stopped working with the changes for
  set_fs() removal.

  This series adds read_iter support for seq_file, and uses those for
  various proc files using seq_file to restore splice read support"

[ Side note: Christoph initially had a scripted "move everything over"
  patch, which looks fine, but I personally would prefer us to actively
  discourage splice() on random files.  So this does just the minimal
  basic core set of proc file op conversions.

  For completeness, and in case people care, that script was

     sed -i -e 's/\.proc_read\(\s*=\s*\)seq_read/\.proc_read_iter\1seq_read_iter/g'

  but I'll wait and see if somebody has a strong argument for using
  splice on random small /proc files before I'd run it on the whole
  kernel.   - Linus ]

* emailed patches from Christoph Hellwig <hch@lst.de>:
  proc "seq files": switch to ->read_iter
  proc "single files": switch to ->read_iter
  proc/stat: switch to ->read_iter
  proc/cpuinfo: switch to ->read_iter
  proc: wire up generic_file_splice_read for iter ops
  seq_file: add seq_read_iter

Pull x86 fixes from Thomas Gleixner:
 "A set of x86 fixes:

   - Use SYM_FUNC_START_WEAK in the mem* ASM functions instead of a
     combination of .weak and SYM_FUNC_START_LOCAL which makes LLVMs
     integrated assembler upset

   - Correct the mitigation selection logic which prevented the related
     prctl to work correctly

   - Make the UV5 hubless system work correctly by fixing up the
     malformed table entries and adding the missing ones"

* tag 'x86-urgent-2020-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/platform/uv: Recognize UV5 hubless system identifier
  x86/platform/uv: Remove spaces from OEM IDs
  x86/platform/uv: Fix missing OEM_TABLE_ID
  x86/speculation: Allow IBPB to be conditionally enabled on CPUs with always-on STIBP
  x86/lib: Change .weak to SYM_FUNC_START_WEAK for arch/x86/lib/mem*_64.S

Pull perf fix from Thomas Gleixner:
 "A single fix for the perf core plugging a memory leak in the address
  filter parser"

* tag 'perf-urgent-2020-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Fix a memory leak in perf_event_parse_addr_filter()

Pull futex fix from Thomas Gleixner:
 "A single fix for the futex code where an intermediate state in the
  underlying RT mutex was not handled correctly and triggering a BUG()
  instead of treating it as another variant of retry condition"

* tag 'locking-urgent-2020-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Handle transient "ownerless" rtmutex state correctly

Pull irq fixes from Thomas Gleixner:
 "A set of fixes for interrupt chip drivers:

   - Fix the fallout of the IPI as interrupt conversion in Kconfig and
     the BCM2836 interrupt chip driver

   - Fixes for interrupt affinity setting and the handling of
     hierarchical irq domains in the SiFive PLIC driver

   - Make the unmapped event handling in the TI SCI driver work
     correctly

   - A few minor fixes and cleanups in various chip drivers and Kconfig"

* tag 'irq-urgent-2020-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  dt-bindings: irqchip: ti, sci-inta: Fix diagram indentation for unmapped events
  irqchip/ti-sci-inta: Add support for unmapped event handling
  dt-bindings: irqchip: ti, sci-inta: Update for unmapped event handling
  irqchip/renesas-intc-irqpin: Merge irlm_bit and needs_irlm
  irqchip/sifive-plic: Fix chip_data access within a hierarchy
  irqchip/sifive-plic: Fix broken irq_set_affinity() callback
  irqchip/stm32-exti: Add all LP timer exti direct events support
  irqchip/bcm2836: Fix missing __init annotation
  irqchip/mips: Drop selection of IRQ_DOMAIN_HIERARCHY
  irqchip/mst: Make mst_intc_of_init static
  irqchip/mst: MST_IRQ should depend on ARCH_MEDIATEK or ARCH_MSTARV7
  genirq: Let GENERIC_IRQ_IPI select IRQ_DOMAIN_HIERARCHY

Pull entry code fix from Thomas Gleixner:
 "A single fix for the generic entry code to correct the wrong
  assumption that the lockdep interrupt state needs not to be
  established before calling the RCU check"

* tag 'core-urgent-2020-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  entry: Fix the incorrect ordering of lockdep and RCU check

Pull powerpc fixes from Michael Ellerman:

 - fix miscompilation with GCC 4.9 by using asm_goto_volatile for put_user()

 - fix for an RCU splat at boot caused by a recent lockdep change

 - fix for a possible deadlock in our EEH debugfs code

 - several fixes for handling of _PAGE_ACCESSED on 32-bit platforms

 - build fix when CONFIG_NUMA=n

Thanks to Andreas Schwab, Christophe Leroy, Oliver O'Halloran, Qian Cai,
and Scott Cheloha.

* tag 'powerpc-5.10-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/numa: Fix build when CONFIG_NUMA=n
  powerpc/8xx: Manage _PAGE_ACCESSED through APG bits in L1 entry
  powerpc/8xx: Always fault when _PAGE_ACCESSED is not set
  powerpc/40x: Always fault when _PAGE_ACCESSED is not set
  powerpc/603: Always fault when _PAGE_ACCESSED is not set
  powerpc: Use asm_goto_volatile for put_user()
  powerpc/smp: Call rcu_cpu_starting() earlier
  powerpc/eeh_cache: Fix a possible debugfs deadlock

Pull block fixes from Jens Axboe:

 - NVMe pull request from Christoph:
    - revert a nvme_queue size optimization (Keith Bush)
    - fabrics timeout races fixes (Chao Leng and Sagi Grimberg)"

 - null_blk zone locking fix (Damien)

* tag 'block-5.10-2020-11-07' of git://git.kernel.dk/linux-block:
  null_blk: Fix scheduling in atomic with zoned mode
  nvme-tcp: avoid repeated request completion
  nvme-rdma: avoid repeated request completion
  nvme-tcp: avoid race between time out and tear down
  nvme-rdma: avoid race between time out and tear down
  nvme: introduce nvme_sync_io_queues
  Revert "nvme-pci: remove last_sq_tail"

Pull io_uring fixes from Jens Axboe:
 "A set of fixes for io_uring:

   - SQPOLL cancelation fixes

   - Two fixes for the io_identity COW

   - Cancelation overflow fix (Pavel)

   - Drain request cancelation fix (Pavel)

   - Link timeout race fix (Pavel)"

* tag 'io_uring-5.10-2020-11-07' of git://git.kernel.dk/linux-block:
  io_uring: fix link lookup racing with link timeout
  io_uring: use correct pointer for io_uring_show_cred()
  io_uring: don't forget to task-cancel drained reqs
  io_uring: fix overflowed cancel w/ linked ->files
  io_uring: drop req/tctx io_identity separately
  io_uring: ensure consistent view of original task ->mm from SQPOLL
  io_uring: properly handle SQPOLL request cancelations
  io-wq: cancel request if it's asking for files and we don't have them

Gratian managed to trigger the BUG_ON(!newowner) in fixup_pi_state_owner().
This is one possible chain of events leading to this:

Task Prio       Operation
T1   120	lock(F)
T2   120	lock(F)   -> blocks (top waiter)
T3   50 (RT)	lock(F)   -> boosts T1 and blocks (new top waiter)
XX   		timeout/  -> wakes T2
		signal
T1   50		unlock(F) -> wakes T3 (rtmutex->owner == NULL, waiter bit is set)
T2   120	cleanup   -> try_to_take_mutex() fails because T3 is the top waiter
     			     and the lower priority T2 cannot steal the lock.
     			  -> fixup_pi_state_owner() sees newowner == NULL -> BUG_ON()

The comment states that this is invalid and rt_mutex_real_owner() must
return a non NULL owner when the trylock failed, but in case of a queued
and woken up waiter rt_mutex_real_owner() == NULL is a valid transient
state. The higher priority waiter has simply not yet managed to take over
the rtmutex.

The BUG_ON() is therefore wrong and this is just another retry condition in
fixup_pi_state_owner().

Drop the locks, so that T3 can make progress, and then try the fixup again.

Gratian provided a great analysis, traces and a reproducer. The analysis is
to the point, but it confused the hell out of that tglx dude who had to
page in all the futex horrors again. Condensed version is above.

[ tglx: Wrote comment and changelog ]

Fixes: c1e2f0ea ("futex: Avoid violating the 10th rule of futex")
Reported-by: Gratian Crisan <gratian.crisan@ni.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87a6w6x7bb.fsf@ni.com
Link: https://lore.kernel.org/r/87sg9pkvf7.fsf@nanos.tec.linutronix.de

Pull i2c fixes from Wolfram Sang:
 "Driver bugfixes for I2C.

  Most of them are for the new mlxbf driver which got more exposure
  after rc1. The sh_mobile patch should already have reached you during
  the merge window, but I accidently dropped it. However, since it fixes
  a problem with rebooting, it is still fine for rc3"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: designware: slave should do WRITE_REQUESTED before WRITE_RECEIVED
  i2c: designware: call i2c_dw_read_clear_intrbits_slave() once
  i2c: mlxbf: I2C_MLXBF should depend on MELLANOX_PLATFORM
  i2c: mlxbf: Update author and maintainer email info
  i2c: mlxbf: Update reference clock frequency
  i2c: mlxbf: Remove unecessary wrapper functions
  i2c: mlxbf: Fix resrticted cast warning of sparse
  i2c: mlxbf: Add CONFIG_ACPI to guard ACPI function call
  i2c: sh_mobile: implement atomic transfers
  i2c: mediatek: move dma reset before i2c reset

Pull RISC-V fixes from Palmer Dabbelt:

 - SPDX comment style fix

 - ignore memory that is unusable

 - avoid setting a kernel text offset for the !MMU kernels, where
   skipping the first page of memory is both unnecessary and costly

 - avoid passing the flag bits in satp to pfn_to_virt()

 - fix __put_kernel_nofault, where we had the arguments to
   __put_user_nocheck reversed

 - workaround for a bug in the FU540 to avoid triggering PMP issues
   during early boot

 - change to how we pull symbols out of the vDSO. The old mechanism was
   removed from binutils-2.35 (and has been backported to Debian's 2.34)

* tag 'riscv-for-linus-5.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  RISC-V: Fix the VDSO symbol generaton for binutils-2.35+
  RISC-V: Use non-PGD mappings for early DTB access
  riscv: uaccess: fix __put_kernel_nofault()
  riscv: fix pfn_to_virt err in do_page_fault().
  riscv: Set text_offset correctly for M-Mode
  RISC-V: Remove any memblock representing unusable memory area
  risc-v: kernel: ftrace: Fixes improper SPDX comment style

Merge tag 'usb-serial-5.10-rc3' of https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial into usb-linus

Johan writes:

USB-serial fixes for 5.10-rc3

Here's a fix for a long-standing issue with the cyberjack driver and
some new device ids.

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

* tag 'usb-serial-5.10-rc3' of https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial:
  USB: serial: option: add Telit FN980 composition 0x1055
  USB: serial: option: add LE910Cx compositions 0x1203, 0x1230, 0x1231
  USB: serial: cyberjack: fix write-URB completion race
  USB: serial: option: add Quectel EC200T module support

As shown through runtime testing, the "filename" allocation is not
always freed in perf_event_parse_addr_filter().

There are three possible ways that this could happen:

 - It could be allocated twice on subsequent iterations through the loop,
 - or leaked on the success path,
 - or on the failure path.

Clean up the code flow to make it obvious that 'filename' is always
freed in the reallocation path and in the two return paths as well.

We rely on the fact that kfree(NULL) is NOP and filename is initialized
with NULL.

This fixes the leak. No other side effects expected.

[ Dan Carpenter: cleaned up the code flow & added a changelog. ]
[ Ingo Molnar: updated the changelog some more. ]

Fixes: 375637bc ("perf/core: Introduce address range filtering")
Signed-off-by: "kiyin(尹亮)" <kiyin@tencent.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: "Srivatsa S. Bhat" <srivatsa@csail.mit.edu>
Cc: Anthony Liguori <aliguori@amazon.com>
--
 kernel/events/core.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

Testing shows a problem in that UV5 hubless systems were not being
recognized.  Add them to the list of OEM IDs checked.

Fixes: 6c779442 ("Add UV5 direct references")
Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201105222741.157029-4-mike.travis@hpe.com

Testing shows that trailing spaces caused problems with the OEM_ID and
the OEM_TABLE_ID.  One being that the OEM_ID would not string compare
correctly.  Another the OEM_ID and OEM_TABLE_ID would be concatenated
in the printout.  Remove any trailing spaces.

Fixes: 1e61f5a9 ("Add and decode Arch Type in UVsystab")
Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201105222741.157029-3-mike.travis@hpe.com

Testing shows a problem in that the OEM_TABLE_ID was missing for
hubless systems.  This is used to determine the APIC type (legacy or
extended).  Add the OEM_TABLE_ID to the early hubless processing.

Fixes: 1e61f5a9 ("Add and decode Arch Type in UVsystab")
Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201105222741.157029-2-mike.travis@hpe.com

Pull ceph fix from Ilya Dryomov:
 "A fix for a potential stall on umount caused by the MDS dropping our
  REQUEST_CLOSE message. The code that handled this case was
  inadvertently disabled in 5.9, this patch removes it entirely and
  fixes the problem in a way that is consistent with ceph-fuse"

* tag 'ceph-for-5.10-rc3' of git://github.com/ceph/ceph-client:
  ceph: check session state after bumping session->s_seq

Merge tag 'linux-kselftest-fixes-5.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull Kselftest fixes from Shuah Khan:
 "Fixes to the ftrace test and several fixes from Tommi Rantala for
  various other tests"

* tag 'linux-kselftest-fixes-5.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  selftests: binderfs: use SKIP instead of XFAIL
  selftests: clone3: use SKIP instead of XFAIL
  selftests: core: use SKIP instead of XFAIL in close_range_test.c
  selftests: proc: fix warning: _GNU_SOURCE redefined
  selftests: pidfd: drop needless linux/kcmp.h inclusion in pidfd_setns_test.c
  selftests: pidfd: add CONFIG_CHECKPOINT_RESTORE=y to config
  selftests: pidfd: skip test on kcmp() ENOSYS
  selftests: pidfd: use ksft_test_result_skip() when skipping test
  selftests/harness: prettify SKIP message whitespace again
  selftests: pidfd: fix compilation errors due to wait.h
  selftests: filter kselftest headers from command in lib.mk
  selftests/ftrace: check for do_sys_openat2 in user-memory test
  selftests/ftrace: Use $FUNCTION_FORK to reference kernel fork function

Pull SCSI fixes from James Bottomley:
 "Three driver fixes. Two (alua and hpsa) are in hard to trigger
  attach/detach situations but the mp3sas one involves a polled to
  interrupt switch over that could trigger in any high IOPS situation"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: mpt3sas: Fix timeouts observed while reenabling IRQ
  scsi: scsi_dh_alua: Avoid crash during alua_bus_detach()
  scsi: hpsa: Fix memory leak in hpsa_init_one()

Pull mtd fixes from Miquel Raynal.

* 'mtd/fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux:
  mtd: rawnand: stm32_fmc2: fix broken ECC
  mtd: spi-nor: Fix address width on flash chips > 16MB
  mtd: spi-nor: Don't copy self-pointing struct around
  mtd: rawnand: ifc: Move the ECC engine initialization to the right place
  mtd: rawnand: mxc: Move the ECC engine initialization to the right place