See the SDM, volume 3, section 4.4.1:

If PAE paging would be in use following an execution of MOV to CR0 or
MOV to CR4 (see Section 4.1.1) and the instruction is modifying any of
CR0.CD, CR0.NW, CR0.PG, CR4.PAE, CR4.PGE, CR4.PSE, or CR4.SMEP; then
the PDPTEs are loaded from the address in CR3.

Fixes: b9baba86 ("KVM, pkeys: expose CPUID/CR4 to guest")
Cc: Huaitong Han <huaitong.han@intel.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Oliver Upton <oupton@google.com>
Message-Id: <20200817181655.3716509-1-jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

See the SDM, volume 3, section 4.4.1:

If PAE paging would be in use following an execution of MOV to CR0 or
MOV to CR4 (see Section 4.1.1) and the instruction is modifying any of
CR0.CD, CR0.NW, CR0.PG, CR4.PAE, CR4.PGE, CR4.PSE, or CR4.SMEP; then
the PDPTEs are loaded from the address in CR3.

Fixes: 0be0226f ("KVM: MMU: fix SMAP virtualization")
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Oliver Upton <oupton@google.com>
Message-Id: <20200817181655.3716509-2-jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The PK bit of the error code is computed dynamically in permission_fault
and therefore need not be passed to gva_to_gpa: only the access bits
(fetch, user, write) need to be passed down.

Not doing so causes a splat in the pku test:

   WARNING: CPU: 25 PID: 5465 at arch/x86/kvm/mmu.h:197 paging64_walk_addr_generic+0x594/0x750 [kvm]
   Hardware name: Intel Corporation WilsonCity/WilsonCity, BIOS WLYDCRB1.SYS.0014.D62.2001092233 01/09/2020
   RIP: 0010:paging64_walk_addr_generic+0x594/0x750 [kvm]
   Code: <0f> 0b e9 db fe ff ff 44 8b 43 04 4c 89 6c 24 30 8b 13 41 39 d0 89
   RSP: 0018:ff53778fc623fb60 EFLAGS: 00010202
   RAX: 0000000000000001 RBX: ff53778fc623fbf0 RCX: 0000000000000007
   RDX: 0000000000000001 RSI: 0000000000000002 RDI: ff4501efba818000
   RBP: 0000000000000020 R08: 0000000000000005 R09: 00000000004000e7
   R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000007
   R13: ff4501efba818388 R14: 10000000004000e7 R15: 0000000000000000
   FS:  00007f2dcf31a700(0000) GS:ff4501f1c8040000(0000) knlGS:0000000000000000
   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   CR2: 0000000000000000 CR3: 0000001dea475005 CR4: 0000000000763ee0
   DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
   DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
   PKRU: 55555554
   Call Trace:
    paging64_gva_to_gpa+0x3f/0xb0 [kvm]
    kvm_fixup_and_inject_pf_error+0x48/0xa0 [kvm]
    handle_exception_nmi+0x4fc/0x5b0 [kvm_intel]
    kvm_arch_vcpu_ioctl_run+0x911/0x1c10 [kvm]
    kvm_vcpu_ioctl+0x23e/0x5d0 [kvm]
    ksys_ioctl+0x92/0xb0
    __x64_sys_ioctl+0x16/0x20
    do_syscall_64+0x3e/0xb0
    entry_SYSCALL_64_after_hwframe+0x44/0xa9
   ---[ end trace d17eb998aee991da ]---
Reported-by: Sean Christopherson <sean.j.christopherson@intel.com>
Fixes: 89786147 ("KVM: x86: Add helper functions for illegal GPA checking and page fault injection")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

If debug_regs.c is built with newer binutils, the resulting binary is "optimized"
by the assembler:

asm volatile("ss_start: "
             "xor %%rax,%%rax\n\t"
             "cpuid\n\t"
             "movl $0x1a0,%%ecx\n\t"
             "rdmsr\n\t"
             : : : "rax", "ecx");

is translated to :

  000000000040194e <ss_start>:
  40194e:       31 c0                   xor    %eax,%eax     <----- rax->eax?
  401950:       0f a2                   cpuid
  401952:       b9 a0 01 00 00          mov    $0x1a0,%ecx
  401957:       0f 32                   rdmsr

As you can see rax is replaced with eax in target binary code.
This causes a difference is the length of xor instruction (2 Byte vs 3 Byte),
and makes the hard-coded instruction length check fail:

        /* Instruction lengths starting at ss_start */
        int ss_size[4] = {
                3,              /* xor */   <-------- 2 or 3?
                2,              /* cpuid */
                5,              /* mov */
                2,              /* rdmsr */
        };

Encode the shorter version directly and, while at it, fix the "clobbers"
of the asm.

Cc: stable@vger.kernel.org
Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Commit c34b26b9 ("KVM: MIPS: clean up redundant 'kvm_run'
parameters") remove the 'kvm_run' parameter in kvm_vz_gpsi_lwc2.

The following build error:

arch/mips/kvm/vz.c: In function 'kvm_trap_vz_handle_gpsi':
arch/mips/kvm/vz.c:1243:43: error: 'run' undeclared (first use in this function)
   er = kvm_vz_gpsi_lwc2(inst, opc, cause, run, vcpu);
                                           ^~~
arch/mips/kvm/vz.c:1243:43: note: each undeclared identifier is reported only
once for each function it appears in
scripts/Makefile.build:283: recipe for target 'arch/mips/kvm/vz.o' failed
make[2]: *** [arch/mips/kvm/vz.o] Error 1
scripts/Makefile.build:500: recipe for target 'arch/mips/kvm' failed
make[1]: *** [arch/mips/kvm] Error 2
Makefile:1785: recipe for target 'arch/mips' failed
make: *** [arch/mips] Error 2
Signed-off-by: Xingxing Su <suxingxing@loongson.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Based on an analysis of the HyperV firmwares (Gen1 and Gen2) it seems
like the SCONTROL is not being set to the ENABLED state as like we have
thought.

Also from a test done by Vitaly Kuznetsov, running a nested HyperV it
was concluded that the first access to the SCONTROL MSR with a read
resulted with the value of 0x1, aka HV_SYNIC_CONTROL_ENABLE.

It's important to note that this diverges from the value states in the
HyperV TLFS of 0.
Signed-off-by: Jon Doron <arilou@gmail.com>
Message-Id: <20200717125238.1103096-2-arilou@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

There is a fallthrough comment being forgotten,
GCC complains about it:

arch/mips/kvm/emulate.c: In function kvm_mips_emulate_load:
arch/mips/kvm/emulate.c:1936:21: error: this statement may fall through
 1936 |   vcpu->mmio_needed = 1; /* unsigned */
      |   ~~~~~~~~~~~~~~~~~~^~~
arch/mips/kvm/emulate.c:1939:2: note: here
 1939 |  case lw_op:

Just fix it.
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Huacai Chen <chenhc@lemote.com>
Message-Id: <20200810011749.3211128-1-jiaxun.yang@flygoat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Only Loongson64 platform has and needs loongson_regs.h, including it
unconditionally will cause build errors.

Fixes: 7f2a83f1 ("KVM: MIPS: Add CPUCFG emulation for Loongson-3")
Cc: stable@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Message-Id: <1596891052-24052-1-git-send-email-chenhc@lemote.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Merge tag 'kvm-ppc-next-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into kvm-next-5.6

PPC KVM update for 5.9

- Improvements and bug-fixes for secure VM support, giving reduced startup
  time and memory hotplug support.
- Locking fixes in nested KVM code
- Increase number of guests supported by HV KVM to 4094
- Preliminary POWER10 support

The SERIALIZE instruction is supported by Tntel processors, like
Sapphire Rapids.  SERIALIZE is a faster serializing instruction which
does not modify registers, arithmetic flags or memory, will not cause VM
exit. It's availability is indicated by CPUID.(EAX=7,ECX=0):ECX[bit 14].

Expose it in KVM supported CPUID.  This way, KVM could pass this
information to guests and they can make use of these features accordingly.
Signed-off-by: Cathy Zhang <cathy.zhang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Merge tag 'kvmarm-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-next-5.6

KVM/arm64 updates for Linux 5.9:

- Split the VHE and nVHE hypervisor code bases, build the EL2 code
  separately, allowing for the VHE code to now be built with instrumentation

- Level-based TLB invalidation support

- Restructure of the vcpu register storage to accomodate the NV code

- Pointer Authentication available for guests on nVHE hosts

- Simplification of the system register table parsing

- MMU cleanups and fixes

- A number of post-32bit cleanups and other fixes

Don't attempt to load PDPTRs if EFER.LME=1, i.e. if 64-bit mode is
enabled.  A recent change to reload the PDTPRs when CR0.CD or CR0.NW is
toggled botched the EFER.LME handling and sends KVM down the PDTPR path
when is_paging() is true, i.e. when the guest toggles CD/NW in 64-bit
mode.

Split the CR0 checks for 64-bit vs. 32-bit PAE into separate paths.  The
64-bit path is specifically checking state when paging is toggled on,
i.e. CR0.PG transititions from 0->1.  The PDPTR path now needs to run if
the new CR0 state has paging enabled, irrespective of whether paging was
already enabled.  Trying to shave a few cycles to make the PDPTR path an
"else if" case is a mess.

Fixes: d42e3fae ("kvm: x86: Read PDPTEs on CR0.CD and CR0.NW changes")
Cc: Jim Mattson <jmattson@google.com>
Cc: Oliver Upton <oupton@google.com>
Cc: Peter Shier <pshier@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20200714015732.32426-1-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Pull arm64 fixes from Catalin Marinas:

 - Fix tegra194-cpufreq module build failure caused by __cpu_logical_map
   not being exported.

 - Improve fixed_addresses comment regarding the fixmap buffer sizes.

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: Fix __cpu_logical_map undefined issue
  arm64/fixmap: make notes of fixed_addresses more precisely

The __cpu_logical_map undefined issue occued when the new
tegra194-cpufreq drvier building as a module.

ERROR: modpost: "__cpu_logical_map" [drivers/cpufreq/tegra194-cpufreq.ko] undefined!

The driver using cpu_logical_map() macro which will expand to
__cpu_logical_map, we can't access it in a drvier. Let's turn
cpu_logical_map() into a C wrapper and export it to fix the
build issue.

Also create a function set_cpu_logical_map(cpu, hwid) when assign
a value to cpu_logical_map(cpu).
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

These 'compile-time allocated' memory buffers can occupy more than one
page and each enum increment is page-sized. So improve the note about it.
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/1596460720-19243-1-git-send-email-kernelfans@gmail.com
To: linux-arm-kernel@lists.infradead.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Pull IPMI updates from Corey Minyard:
 "Minor cleanups to the IPMI driver for 5.9

  Nothing of any major consequence. Duplicate code, some missing \n's in
  sysfs files, some documentation and comment changes"

* tag 'for-linus-5.9-1' of git://github.com/cminyard/linux-ipmi:
  ipmi/watchdog: add missing newlines when printing parameters by sysfs
  ipmi: remve duplicate code in __ipmi_bmc_register()
  ipmi: ssif: Remove finished TODO comment about SMBus alert
  Doc: driver-api: ipmi: Add description of alerts_broken module param

Pull power supply and reset updates from Sebastian Reichel:
 "Power-supply core:
   - add COOL/WARM/HOT state from JEITA JISC8712:2015 specification
   - convert simple-battery DT binding to YAML
   - add long-life charging mode

 Battery/charger drivers:
   - bq25150: new charger driver
   - bq27xxx: add support for BQ27z561 and BQ28z610
   - max17040: support CAPACITY_ALERT_MIN
   - sbs-battery: add PEC support
   - wilco-ec: support long-life charging mode
   - bq25890: fix DT binding
   - misc. fixes and cleanups

 Reset drivers:
   - linkstation: new reset driver"

* tag 'for-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply: (32 commits)
  power: supply: wilco_ec: Add long life charging mode
  power: supply: bq27xxx_battery: Add the BQ28z610 Battery monitor
  dt-bindings: power: Add BQ28z610 compatible
  power: supply: bq27xxx_battery: Add the BQ27Z561 Battery monitor
  dt-bindings: power: Add BQ27Z561 compatible
  power: supply: test_power: Fix battery_current initial value
  power: supply: Fix kerneldoc of power_supply_temp2resist_simple()
  power: supply: cpcap-battery: Fix kerneldoc of cpcap_battery_read_accumulated()
  dt-bindings: power: Convert battery.txt to battery.yaml
  power: supply: rt5033_battery: Fix error code in rt5033_battery_probe()
  power: supply: max17040: Add POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN
  power: supply: check if calc_soc succeeded in pm860x_init_battery
  power: supply: bq2xxxx: Replace HTTP links with HTTPS ones
  power: reset: add driver for LinkStation power off
  power: supply: sc27xx: prevent adc * 1000 from overflow
  math64: New DIV_S64_ROUND_CLOSEST helper
  power: fix duplicated words in bq2415x_charger.h
  power: Convert to DEFINE_SHOW_ATTRIBUTE
  power: reset: keystone-reset: Replace HTTP links with HTTPS ones
  power: supply: bq25150 introduce the bq25150
  ...

Pull misc vfs updates from Al Viro:
 "No common topic whatsoever in those, sorry"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: define inode flags using bit numbers
  iov_iter: Move unnecessary inclusion of crypto/hash.h
  dlmfs: clean up dlmfs_file_{read,write}() a bit

Pull mount leak fix from Al Viro:
 "Regression fix for the syscalls-for-init series - fix a leak of a 'struct path'"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: fix a struct path leak in path_umount

Pull PCI updates from Bjorn Helgaas:
 "Enumeration:
   - Fix pci_cfg_wait queue locking problem (Bjorn Helgaas)
   - Convert PCIe capability PCIBIOS errors to errno (Bolarinwa Olayemi
     Saheed)
   - Align PCIe capability and PCI accessor return values (Bolarinwa
     Olayemi Saheed)
   - Fix pci_create_slot() reference count leak (Qiushi Wu)
   - Announce device after early fixups (Tiezhu Yang)

  PCI device hotplug:
   - Make rpadlpar functions static (Wei Yongjun)

  Driver binding:
   - Add device even if driver attach failed (Rajat Jain)

  Virtualization:
   - xen: Remove redundant initialization of irq (Colin Ian King)

  IOMMU:
   - Add pci_pri_supported() to check device or associated PF (Ashok Raj)
   - Release IVRS table in AMD ACS quirk (Hanjun Guo)
   - Mark AMD Navi10 GPU rev 0x00 ATS as broken (Kai-Heng Feng)
   - Treat "external-facing" devices themselves as internal (Rajat Jain)

  MSI:
   - Forward MSI-X error code in pci_alloc_irq_vectors_affinity() (Piotr
     Stankiewicz)

  Error handling:
   - Clear PCIe Device Status errors only if OS owns AER (Jonathan
     Cameron)
   - Log correctable errors as warning, not error (Matt Jolly)
   - Use 'pci_channel_state_t' instead of 'enum pci_channel_state' (Luc
     Van Oostenryck)

  Peer-to-peer DMA:
   - Allow P2PDMA on AMD Zen and newer CPUs (Logan Gunthorpe)

  ASPM:
   - Add missing newline in sysfs 'policy' (Xiongfeng Wang)

  Native PCIe controllers:
   - Convert to devm_platform_ioremap_resource_byname() (Dejin Zheng)
   - Convert to devm_platform_ioremap_resource() (Dejin Zheng)
   - Remove duplicate error message from devm_pci_remap_cfg_resource()
     callers (Dejin Zheng)
   - Fix runtime PM imbalance on error (Dinghao Liu)
   - Remove dev_err() when handing an error from platform_get_irq()
     (Krzysztof Wilczyński)
   - Use pci_host_bridge.windows list directly instead of splicing in a
     temporary list for cadence, mvebu, host-common (Rob Herring)
   - Use pci_host_probe() instead of open-coding all the pieces for
     altera, brcmstb, iproc, mobiveil, rcar, rockchip, tegra, v3,
     versatile, xgene, xilinx, xilinx-nwl (Rob Herring)
   - Default host bridge parent device to the platform device (Rob
     Herring)
   - Use pci_is_root_bus() instead of tracking root bus number
     separately in aardvark, designware (imx6, keystone,
     designware-host), mobiveil, xilinx-nwl, xilinx, rockchip, rcar (Rob
     Herring)
   - Set host bridge bus number in pci_scan_root_bus_bridge() instead of
     each driver for aardvark, designware-host, host-common, mediatek,
     rcar, tegra, v3-semi (Rob Herring)
   - Move DT resource setup into devm_pci_alloc_host_bridge() (Rob
     Herring)
   - Set bridge map_irq and swizzle_irq to default functions; drivers
     that don't support legacy IRQs (iproc) need to undo this (Rob
     Herring)

  ARM Versatile PCIe controller driver:
   - Drop flag PCI_ENABLE_PROC_DOMAINS (Rob Herring)

  Cadence PCIe controller driver:
   - Use "dma-ranges" instead of "cdns,no-bar-match-nbits" property
     (Kishon Vijay Abraham I)
   - Remove "mem" from reg binding (Kishon Vijay Abraham I)
   - Fix cdns_pcie_{host|ep}_setup() error path (Kishon Vijay Abraham I)
   - Convert all r/w accessors to perform only 32-bit accesses (Kishon
     Vijay Abraham I)
   - Add support to start link and verify link status (Kishon Vijay
     Abraham I)
   - Allow pci_host_bridge to have custom pci_ops (Kishon Vijay Abraham I)
   - Add new *ops* for CPU addr fixup (Kishon Vijay Abraham I)
   - Fix updating Vendor ID and Subsystem Vendor ID register (Kishon
     Vijay Abraham I)
   - Use bridge resources for outbound window setup (Rob Herring)
   - Remove private bus number and range storage (Rob Herring)

  Cadence PCIe endpoint driver:
   - Add MSI-X support (Alan Douglas)

  HiSilicon PCIe controller driver:
   - Remove non-ECAM HiSilicon hip05/hip06 driver (Rob Herring)

  Intel VMD host bridge driver:
   - Use Shadow MEMBAR registers for QEMU/KVM guests (Jon Derrick)

  Loongson PCIe controller driver:
   - Use DECLARE_PCI_FIXUP_EARLY for bridge_class_quirk() (Tiezhu Yang)

  Marvell Aardvark PCIe controller driver:
   - Indicate error in 'val' when config read fails (Pali Rohár)
   - Don't touch PCIe registers if no card connected (Pali Rohár)

  Marvell MVEBU PCIe controller driver:
   - Setup BAR0 in order to fix MSI (Shmuel Hazan)

  Microsoft Hyper-V host bridge driver:
   - Fix a timing issue which causes kdump to fail occasionally (Wei Hu)
   - Make some functions static (Wei Yongjun)

  NVIDIA Tegra PCIe controller driver:
   - Revert tegra124 raw_violation_fixup (Nicolas Chauvet)
   - Remove PLL power supplies (Thierry Reding)

  Qualcomm PCIe controller driver:
   - Change duplicate PCI reset to phy reset (Abhishek Sahu)
   - Add missing ipq806x clocks in PCIe driver (Ansuel Smith)
   - Add missing reset for ipq806x (Ansuel Smith)
   - Add ext reset (Ansuel Smith)
   - Use bulk clk API and assert on error (Ansuel Smith)
   - Add support for tx term offset for rev 2.1.0 (Ansuel Smith)
   - Define some PARF params needed for ipq8064 SoC (Ansuel Smith)
   - Add ipq8064 rev2 variant (Ansuel Smith)
   - Support PCI speed set for ipq806x (Sham Muthayyan)

  Renesas R-Car PCIe controller driver:
   - Use devm_pci_alloc_host_bridge() (Rob Herring)
   - Use struct pci_host_bridge.windows list directly (Rob Herring)
   - Convert rcar-gen2 to use modern host bridge probe functions (Rob
     Herring)

  TI J721E PCIe driver:
   - Add TI J721E PCIe host and endpoint driver (Kishon Vijay Abraham I)

  Xilinx Versal CPM PCIe controller driver:
   - Add Versal CPM Root Port driver and YAML schema (Bharat Kumar
     Gogada)

  MicroSemi Switchtec management driver:
   - Add missing __iomem and __user tags to fix sparse warnings (Logan
     Gunthorpe)

  Miscellaneous:
   - Replace http:// links with https:// (Alexander A. Klimov)
   - Replace lkml.org, spinics, gmane with lore.kernel.org (Bjorn
     Helgaas)
   - Remove unused pci_lost_interrupt() (Heiner Kallweit)
   - Move PCI_VENDOR_ID_REDHAT definition to pci_ids.h (Huacai Chen)
   - Fix kerneldoc warnings (Krzysztof Kozlowski)"

* tag 'pci-v5.9-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (113 commits)
  PCI: Fix kerneldoc warnings
  PCI: xilinx-cpm: Add Versal CPM Root Port driver
  PCI: xilinx-cpm: Add YAML schemas for Versal CPM Root Port
  PCI: Set bridge map_irq and swizzle_irq to default functions
  PCI: Move DT resource setup into devm_pci_alloc_host_bridge()
  PCI: rcar-gen2: Convert to use modern host bridge probe functions
  PCI: Remove dev_err() when handing an error from platform_get_irq()
  MAINTAINERS: Add Kishon Vijay Abraham I for TI J721E SoC PCIe
  misc: pci_endpoint_test: Add J721E in pci_device_id table
  PCI: j721e: Add TI J721E PCIe driver
  PCI: switchtec: Add missing __iomem tag to fix sparse warnings
  PCI: switchtec: Add missing __iomem and __user tags to fix sparse warnings
  PCI: rpadlpar: Make functions static
  PCI/P2PDMA: Allow P2PDMA on AMD Zen and newer CPUs
  PCI: Release IVRS table in AMD ACS quirk
  PCI: Announce device after early fixups
  PCI: Mark AMD Navi10 GPU rev 0x00 ATS as broken
  PCI: Remove unused pci_lost_interrupt()
  dt-bindings: PCI: Add EP mode dt-bindings for TI's J721E SoC
  dt-bindings: PCI: Add host mode dt-bindings for TI's J721E SoC
  ...

Pull tracing updates from Steven Rostedt:

 - The biggest news in that the tracing ring buffer can now time events
   that interrupted other ring buffer events.

   Before this change, if an interrupt came in while recording another
   event, and that interrupt also had an event, those events would all
   have the same time stamp as the event it interrupted.

   Now, with the new design, those events will have a unique time stamp
   and rightfully display the time for those events that were recorded
   while interrupting another event.

 - Bootconfig how has an "override" operator that lets the users have a
   default config, but then add options to override the default.

 - A fix was made to properly filter function graph tracing to the
   ftrace PIDs. This came in at the end of the -rc cycle, and needs to
   be backported.

 - Several clean ups, performance updates, and minor fixes as well.

* tag 'trace-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (39 commits)
  tracing: Add trace_array_init_printk() to initialize instance trace_printk() buffers
  kprobes: Fix compiler warning for !CONFIG_KPROBES_ON_FTRACE
  tracing: Use trace_sched_process_free() instead of exit() for pid tracing
  bootconfig: Fix to find the initargs correctly
  Documentation: bootconfig: Add bootconfig override operator
  tools/bootconfig: Add testcases for value override operator
  lib/bootconfig: Add override operator support
  kprobes: Remove show_registers() function prototype
  tracing/uprobe: Remove dead code in trace_uprobe_register()
  kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler
  ftrace: Fix ftrace_trace_task return value
  tracepoint: Use __used attribute definitions from compiler_attributes.h
  tracepoint: Mark __tracepoint_string's __used
  trace : Have tracing buffer info use kvzalloc instead of kzalloc
  tracing: Remove outdated comment in stack handling
  ftrace: Do not let direct or IPMODIFY ftrace_ops be added to module and set trampolines
  ftrace: Setup correct FTRACE_FL_REGS flags for module
  tracing/hwlat: Honor the tracing_cpumask
  tracing/hwlat: Drop the duplicate assignment in start_kthread()
  tracing: Save one trace_event->type by using __TRACE_LAST_TYPE
  ...

The merge resolution in commit 25d8d4ee left ret no longer used,
leading to:

  arch/powerpc/kernel/ptrace/ptrace-view.c: In function ‘pkey_get’:
  arch/powerpc/kernel/ptrace/ptrace-view.c:473:6: error: unused variable ‘ret’
    473 |  int ret;

Fix it by removing ret.

Fixes: 25d8d4ee ("Merge tag 'powerpc-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Make sure we also put the dentry and vfsmnt in the illegal flags
and !may_umount cases.

Fixes: 41525f56 ("fs: refactor ksys_umount")
Reported-by: Vikas Kumar <vikas.kumar2@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

As trace_array_printk() used with not global instances will not add noise to
the main buffer, they are OK to have in the kernel (unlike trace_printk()).
This require the subsystem to create their own tracing instance, and the
trace_array_printk() only writes into those instances.

Add trace_array_init_printk() to initialize the trace_printk() buffers
without printing out the WARNING message.
Reported-by: Sean Paul <sean@poorly.run>
Reviewed-by: Sean Paul <sean@poorly.run>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull clk updates from Stephen Boyd:
 "It looks like a smaller batch of clk updates this time around.

  In the core framework we just have some minor tweaks and a debugfs
  feature, so not much to see there. The driver updates are fairly well
  split between AT91 and Qualcomm clk support. Adding those two drivers
  together equals about 50% of the diffstat.

  Otherwise, the big amount of work this time was on supporting
  Broadcom's Raspberry Pi firmware clks.

  Highlights:

  Core:
   - Document clk_hw_round_rate() so it gets some more use
   - Remove unused __clk_get_flags()
   - Add a prepare/enable debugfs feature similar to rate setting

  New Drivers:
   - Add support for SAMA7G5 SoC clks
   - Enable CPU clks on Qualcomm IPQ6018 SoCs
   - Enable CPU clks on Qualcomm MSM8996 SoCs
   - GPU clk support for Qualcomm SM8150 and SM8250 SoCs
   - Audio clks on Qualcomm SC7180 SoCs
   - Microchip Sparx5 DPLL clk
   - Add support for the new Renesas RZ/G2H (R8A774E1) SoC

  Updates:
   - Make defines for bcm63xx-gate clks to use in DT
   - Support BCM2711 SoC firmware clks
   - Add HDMI clks for BCM2711 SoCs
   - Add RTC related clks on Ingenic SoCs
   - Support USB PHY clks on Ingenic SoCs
   - Support gate clks on BCM6318 SoCs
   - RMU and DMAC/GPIO clock support for Actions Semi S500 SoCs
   - Use poll_timeout functions in Rockchip clk driver
   - Support Rockchip rk3288w SoC variant
   - Mark mac_lbtest critical on Rockchip rk3188
   - Add CAAM clock support for i.MX vf610 driver
   - Add MU root clock support for i.MX imx8mp driver
   - Amlogic g12: add neural network accelerator clock sources
   - Amlogic meson8: remove critical flag for main PLL divider
   - Amlogic meson8: add video decoder clock gates
   - Convert one more Renesas DT binding to json-schema
   - Enhance critical clock handling on Renesas platforms to only
     consider clocks that were enabled at boot time"

* tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux: (79 commits)
  clk: qcom: gcc: Make disp gpll0 branch aon for sc7180/sdm845
  ipq806x: gcc: add support for child probe
  clk: qcom: msm8996: Make symbol 'cpu_msm8996_clks' static
  clk: qcom: ipq8074: Add correct index for PCIe clocks
  clk: <linux/clk-provider.h>: drop a duplicated word
  clk: renesas: cpg-mssr: Add r8a774e1 support
  dt-bindings: clock: renesas,cpg-mssr: Document r8a774e1
  clk: Drop duplicate selection in Kconfig
  clk: qcom: smd: Add support for MSM8992/4 rpm clocks
  clk: qcom: ipq8074: Add missing clocks for pcie
  dt-bindings: clock: qcom: ipq8074: Add missing bindings for PCIe
  Replace HTTP links with HTTPS ones: Common CLK framework
  clk: qcom: Add CPU clock driver for msm8996
  dt-bindings: clk: qcom: Add bindings for CPU clock for msm8996
  soc: qcom: Separate kryo l2 accessors from PMU driver
  clk: meson: meson8b: add the vclk2_en gate clock
  clk: meson: meson8b: add the vclk_en gate clock
  clk: qcom: Fix return value check in apss_ipq6018_probe()
  clk: bcm: dvp: Add missing module informations
  clk: meson: meson8b: Drop CLK_IS_CRITICAL from fclk_div2
  ...

Pull fdpick coredump update from Al Viro:
 "Switches fdpic coredumps away from original aout dumping primitives to
  the same kind of regset use as regular elf coredumps do"

* 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  [elf-fdpic] switch coredump to regsets
  [elf-fdpic] use elf_dump_thread_status() for the dumper thread as well
  [elf-fdpic] move allocation of elf_thread_status into elf_dump_thread_status()
  [elf-fdpic] coredump: don't bother with cyclic list for per-thread objects
  kill elf_fpxregs_t
  take fdpic-related parts of elf_prstatus out
  unexport linux/elfcore.h

Merge tag 'kallsyms_show_value-fix-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull sysfs module section fix from Kees Cook:
 "Fix sysfs module section output overflow.

  About a month after my kallsyms_show_value() refactoring landed, 0day
  noticed that there was a path through the kernfs binattr read handlers
  that did not have PAGE_SIZEd buffers, and the module "sections" read
  handler made a bad assumption about this, resulting in it stomping on
  memory when reached through small-sized splice() calls.

  I've added a set of tests to find these kinds of regressions more
  quickly in the future as well"
Sefltests-acked-by: Shuah Khan <skhan@linuxfoundation.org>

* tag 'kallsyms_show_value-fix-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  selftests: splice: Check behavior of full and short splices
  module: Correctly truncate sysfs sections output

Pull seccomp fix from Kees Cook:
 "This fixes my typo in the SCM_RIGHTS refactoring that broke compat
  handling.

  Thanks to Thadeu Lima de Souza Cascardo for tracking it down, and to
  Christian Zigotzky and Alex Xu for their reports"

* tag 'seccomp-v5.9-rc1-fix1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  net/scm: Fix typo in SCM_RIGHTS compat refactoring

Pull more power management updates from Rafael Wysocki:
 "These are mostly ARM cpufreq driver updates plus a cpufreq core
  cleanup, an ARM-wide change to make schedutil the default scaling
  governor, an intel_pstate driver fix and some runtime PM changes
  regarding kerneldoc comments.

  Specifics:

   - Add adaptive voltage scaling (AVS) support to the brcmstb cpufreq
     driver and clean it up (Florian Fainelli, Markus Mayer).

   - Add a new Tegra cpufreq driver and clean up the existing one (Jon
     Hunter, Sumit Gupta).

   - Add bandwidth level support to the Qcom cpufreq driver along with
     OPP changes (Sibi Sankar).

   - Clean up the sti, cpufreq-dt, ap806, CPPC cpufreq drivers (Viresh
     Kumar, Lee Jones, Ivan Kokshaysky, Sven Auhagen, Xin Hao).

   - Make schedutil the default governor for ARM (Valentin Schneider).

   - Fix dependency issues for the imx cpufreq driver (Walter Lozano).

   - Clean up cached_resolved_idx handlihng in the cpufreq core (Viresh
     Kumar).

   - Fix the intel_pstate driver to use the correct maximum frequency
     value when MSR_TURBO_RATIO_LIMIT is 0 (Srinivas Pandruvada).

   - Provide kenrneldoc comments for multiple runtime PM helpers and
     improve the pm_runtime_get_if_active() kerneldoc (Rafael Wysocki)"

* tag 'pm-5.9-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (22 commits)
  cpufreq: intel_pstate: Fix cpuinfo_max_freq when MSR_TURBO_RATIO_LIMIT is 0
  PM: runtime: Improve kerneldoc of pm_runtime_get_if_active()
  PM: runtime: Add kerneldoc comments to multiple helpers
  cpufreq: make schedutil the default for arm and arm64
  cpufreq: cached_resolved_idx can not be negative
  cpufreq: Add Tegra194 cpufreq driver
  dt-bindings: arm: Add NVIDIA Tegra194 CPU Complex binding
  cpufreq: imx: Select NVMEM_IMX_OCOTP
  cpufreq: sti-cpufreq: Fix some formatting and misspelling issues
  cpufreq: tegra186: Simplify probe return path
  cpufreq: CPPC: Reuse caps variable in few routines
  cpufreq: ap806: fix cpufreq driver needs ap cpu clk
  cpufreq: cppc: Reorder code and remove apply_hisi_workaround variable
  cpufreq: dt: fix oops on armada37xx
  cpufreq: brcmstb-avs-cpufreq: send S2_ENTER / S2_EXIT commands to AVS
  cpufreq: brcmstb-avs-cpufreq: Support polling AVS firmware
  cpufreq: brcmstb-avs-cpufreq: more flexible interface for __issue_avs_command()
  cpufreq: qcom: Disable fast switch when scaling DDR/L3
  cpufreq: qcom: Update the bandwidth levels on frequency change
  OPP: Add and export helper to set bandwidth
  ...

Merge tag 'for-5.9/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - DM multipath locking fixes around m->flags tests and improvements to
   bio-based code so that it follows patterns established by
   request-based code.

 - Request-based DM core improvement to eliminate unnecessary call to
   blk_mq_queue_stopped().

 - Add "panic_on_corruption" error handling mode to DM verity target.

 - DM bufio fix to to perform buffer cleanup from a workqueue rather
   than wait for IO in reclaim context from shrinker.

 - DM crypt improvement to optionally avoid async processing via
   workqueues for reads and/or writes -- via "no_read_workqueue" and
   "no_write_workqueue" features. This more direct IO processing
   improves latency and throughput with faster storage. Avoiding
   workqueue IO submission for writes (DM_CRYPT_NO_WRITE_WORKQUEUE) is a
   requirement for adding zoned block device support to DM crypt.

 - Add zoned block device support to DM crypt. Makes use of
   DM_CRYPT_NO_WRITE_WORKQUEUE and a new optional feature
   (DM_CRYPT_WRITE_INLINE) that allows write completion to wait for
   encryption to complete. This allows write ordering to be preserved,
   which is needed for zoned block devices.

 - Fix DM ebs target's check for REQ_OP_FLUSH.

 - Fix DM core's report zones support to not report more zones than were
   requested.

 - A few small compiler warning fixes.

 - DM dust improvements to return output directly to the user rather
   than require they scrape the system log for output.

* tag 'for-5.9/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm: don't call report zones for more than the user requested
  dm ebs: Fix incorrect checking for REQ_OP_FLUSH
  dm init: Set file local variable static
  dm ioctl: Fix compilation warning
  dm raid: Remove empty if statement
  dm verity: Fix compilation warning
  dm crypt: Enable zoned block device support
  dm crypt: add flags to optionally bypass kcryptd workqueues
  dm bufio: do buffer cleanup from a workqueue
  dm rq: don't call blk_mq_queue_stopped() in dm_stop_queue()
  dm dust: add interface to list all badblocks
  dm dust: report some message results directly back to user
  dm verity: add "panic_on_corruption" error handling mode
  dm mpath: use double checked locking in fast path
  dm mpath: rename current_pgpath to pgpath in multipath_prepare_ioctl
  dm mpath: rework __map_bio()
  dm mpath: factor out multipath_queue_bio
  dm mpath: push locking down to must_push_back_rq()
  dm mpath: take m->lock spinlock when testing QUEUE_IF_NO_PATH
  dm mpath: changes from initial m->flags locking audit

Pull media updates from Mauro Carvalho Chehab:

 - Legacy soc_camera driver was removed from staging

 - New I2C sensor related drivers: dw9768, ch7322, max9271, rdacm20

 - TI vpe driver code was re-organized and had new features added

 - Added Xilinx MIPI CSI-2 Rx Subsystem driver

 - Added support for Infrared Toy and IR Droid devices

 - Lots of random driver fixes, new features and cleanups

* tag 'media/v5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (318 commits)
  media: camss: fix memory leaks on error handling paths in probe
  media: davinci: vpif_capture: fix potential double free
  media: radio: remove redundant assignment to variable retval
  media: allegro: fix potential null dereference on header
  media: mtk-mdp: Fix a refcounting bug on error in init
  media: allegro: fix an error pointer vs NULL check
  media: meye: fix missing pm_mchip_mode field
  media: cafe-driver: use generic power management
  media: saa7164: use generic power management
  media: v4l2-dev/ioctl: Fix document for VIDIOC_QUERYCAP
  media: v4l2: Correct kernel-doc inconsistency
  media: v4l2: Correct kernel-doc inconsistency
  media: dvbdev.h: keep * together with the type
  media: v4l2-subdev.h: keep * together with the type
  media: videobuf2: Print videobuf2 buffer state by name
  media: colorspaces-details.rst: fix V4L2_COLORSPACE_JPEG description
  media: tw68: use generic power management
  media: meye: use generic power management
  media: cx88: use generic power management
  media: cx25821: use generic power management
  ...

Pull mailbox updates from Jassi Brar:
 "mediatek:
   - add support for mt6779 gce
   - shutdown cleanup and address shift support

  qcom:
   - add msm8994 apcs and sdm660 hmss compatibility

  imx:
   - mark PM funcs __maybe

  pcc:
   - put acpi table before bailout

  misc:
   - replace http with https links"

* tag 'mailbox-v5.9' of git://git.linaro.org/landing-teams/working/fujitsu/integration:
  mailbox: mediatek: cmdq: clear task in channel before shutdown
  mailbox: cmdq: support mt6779 gce platform definition
  mailbox: cmdq: variablize address shift in platform
  dt-binding: gce: add gce header file for mt6779
  mailbox: qcom: Add msm8994 apcs compatible
  mailbox: qcom: Add sdm660 hmss compatible
  mailbox: imx: Mark PM functions as __maybe_unused
  mailbox: pcc: Put the PCCT table for error path
  mailbox: Replace HTTP links with HTTPS ones

When refactoring the SCM_RIGHTS code, I accidentally mis-merged my
native/compat diffs, which entirely broke using SCM_RIGHTS in compat
mode. Use the correct helper.
Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Link: https://lists.ozlabs.org/pipermail/linuxppc-dev/2020-August/216156.htmlReported-by: "Alex Xu (Hello71)" <alex_y_xu@yahoo.ca>
Link: https://lore.kernel.org/lkml/1596812929.lz7fuo8r2w.none@localhost/Suggested-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Fixes: c0029de5 ("net/scm: Regularize compat handling of scm_detach_fds()")
Tested-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Kees Cook <keescook@chromium.org>

Pull dmaengine updates from Vinod Koul:
 "Core:
   - Support out of order dma completion
   - Support for repeating transaction

  New controllers:
   - Support for Actions S700 DMA engine
   - Renesas R8A774E1, r8a7742 controller binding
   - New driver for Xilinx DPDMA controller

  Other:
   - Support of out of order dma completion in idxd driver
   - W=1 warning cleanup of subsystem
   - Updates to ti-k3-dma, dw, idxd drivers"

* tag 'dmaengine-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine: (68 commits)
  dmaengine: dw: Don't include unneeded header to platform data header
  dmaengine: Actions: Add support for S700 DMA engine
  dmaengine: Actions: get rid of bit fields from dma descriptor
  dt-bindings: dmaengine: convert Actions Semi Owl SoCs bindings to yaml
  dmaengine: idxd: add missing invalid flags field to completion
  dmaengine: dw: Initialize max_sg_burst capability
  dmaengine: dw: Introduce max burst length hw config
  dmaengine: dw: Initialize min and max burst DMA device capability
  dmaengine: dw: Set DMA device max segment size parameter
  dmaengine: dw: Take HC_LLP flag into account for noLLP auto-config
  dmaengine: Introduce DMA-device device_caps callback
  dmaengine: Introduce max SG burst capability
  dmaengine: Introduce min burst length capability
  dt-bindings: dma: dw: Add max burst transaction length property
  dt-bindings: dma: dw: Convert DW DMAC to DT binding
  dmaengine: ti: k3-udma: Query throughput level information from hardware
  dmaengine: ti: k3-udma: Use defines for capabilities register parsing
  dmaengine: xilinx: dpdma: Fix kerneldoc warning
  dmaengine: xilinx: dpdma: add missing kernel doc
  dmaengine: xilinx: dpdma: remove comparison of unsigned expression
  ...

Merge misc updates from Andrew Morton:

 - a few MM hotfixes

 - kthread, tools, scripts, ntfs and ocfs2

 - some of MM

Subsystems affected by this patch series: kthread, tools, scripts, ntfs,
ocfs2 and mm (hofixes, pagealloc, slab-generic, slab, slub, kcsan,
debug, pagecache, gup, swap, shmem, memcg, pagemap, mremap, mincore,
sparsemem, vmalloc, kasan, pagealloc, hugetlb and vmscan).

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (162 commits)
  mm: vmscan: consistent update to pgrefill
  mm/vmscan.c: fix typo
  khugepaged: khugepaged_test_exit() check mmget_still_valid()
  khugepaged: retract_page_tables() remember to test exit
  khugepaged: collapse_pte_mapped_thp() protect the pmd lock
  khugepaged: collapse_pte_mapped_thp() flush the right range
  mm/hugetlb: fix calculation of adjust_range_if_pmd_sharing_possible
  mm: thp: replace HTTP links with HTTPS ones
  mm/page_alloc: fix memalloc_nocma_{save/restore} APIs
  mm/page_alloc.c: skip setting nodemask when we are in interrupt
  mm/page_alloc: fallbacks at most has 3 elements
  mm/page_alloc: silence a KASAN false positive
  mm/page_alloc.c: remove unnecessary end_bitidx for [set|get]_pfnblock_flags_mask()
  mm/page_alloc.c: simplify pageblock bitmap access
  mm/page_alloc.c: extract the common part in pfn_to_bitidx()
  mm/page_alloc.c: replace the definition of NR_MIGRATETYPE_BITS with PB_migratetype_bits
  mm/shuffle: remove dynamic reconfiguration
  mm/memory_hotplug: document why shuffle_zone() is relevant
  mm/page_alloc: remove nr_free_pagecache_pages()
  mm: remove vm_total_pages
  ...

The vmstat pgrefill is useful together with pgscan and pgsteal stats to
measure the reclaim efficiency.  However vmstat's pgrefill is not updated
consistently at system level.  It gets updated for both global and memcg
reclaim however pgscan and pgsteal are updated for only global reclaim.
So, update pgrefill only for global reclaim.  If someone is interested in
the stats representing both system level as well as memcg level reclaim,
then consult the root memcg's memory.stat instead of /proc/vmstat.
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Chris Down <chris@chrisdown.name>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Link: http://lkml.kernel.org/r/20200711011459.1159929-1-shakeelb@google.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Change "optizimation" to "optimization".
Signed-off-by: dylan-meiners <spacct.spacct@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: http://lkml.kernel.org/r/20200609185144.10049-1-spacct.spacct@gmail.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Move collapse_huge_page()'s mmget_still_valid() check into
khugepaged_test_exit() itself.  collapse_huge_page() is used for anon THP
only, and earned its mmget_still_valid() check because it inserts a huge
pmd entry in place of the page table's pmd entry; whereas
collapse_file()'s retract_page_tables() or collapse_pte_mapped_thp()
merely clears the page table's pmd entry.  But core dumping without mmap
lock must have been as open to mistaking a racily cleared pmd entry for a
page table at physical page 0, as exit_mmap() was.  And we certainly have
no interest in mapping as a THP once dumping core.

Fixes: 59ea6d06 ("coredump: fix race condition between collapse_huge_page() and core dumping")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>	[4.8+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021217020.27773@eggly.anvilsSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Only once have I seen this scenario (and forgot even to notice what forced
the eventual crash): a sequence of "BUG: Bad page map" alerts from
vm_normal_page(), from zap_pte_range() servicing exit_mmap();
pmd:00000000, pte values corresponding to data in physical page 0.

The pte mappings being zapped in this case were supposed to be from a huge
page of ext4 text (but could as well have been shmem): my belief is that
it was racing with collapse_file()'s retract_page_tables(), found *pmd
pointing to a page table, locked it, but *pmd had become 0 by the time
start_pte was decided.

In most cases, that possibility is excluded by holding mmap lock; but
exit_mmap() proceeds without mmap lock.  Most of what's run by khugepaged
checks khugepaged_test_exit() after acquiring mmap lock:
khugepaged_collapse_pte_mapped_thps() and hugepage_vma_revalidate() do so,
for example.  But retract_page_tables() did not: fix that.

The fix is for retract_page_tables() to check khugepaged_test_exit(),
after acquiring mmap lock, before doing anything to the page table.
Getting the mmap lock serializes with __mmput(), which briefly takes and
drops it in __khugepaged_exit(); then the khugepaged_test_exit() check on
mm_users makes sure we don't touch the page table once exit_mmap() might
reach it, since exit_mmap() will be proceeding without mmap lock, not
expecting anyone to be racing with it.

Fixes: f3f0e1d2 ("khugepaged: add support of collapse for tmpfs/shmem pages")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org>	[4.8+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021215400.27773@eggly.anvilsSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When retract_page_tables() removes a page table to make way for a huge
pmd, it holds huge page lock, i_mmap_lock_write, mmap_write_trylock and
pmd lock; but when collapse_pte_mapped_thp() does the same (to handle the
case when the original mmap_write_trylock had failed), only
mmap_write_trylock and pmd lock are held.

That's not enough.  One machine has twice crashed under load, with "BUG:
spinlock bad magic" and GPF on 6b6b6b6b6b6b6b6b.  Examining the second
crash, page_vma_mapped_walk_done()'s spin_unlock of pvmw->ptl (serving
page_referenced() on a file THP, that had found a page table at *pmd)
discovers that the page table page and its lock have already been freed by
the time it comes to unlock.

Follow the example of retract_page_tables(), but we only need one of huge
page lock or i_mmap_lock_write to secure against this: because it's the
narrower lock, and because it simplifies collapse_pte_mapped_thp() to know
the hpage earlier, choose to rely on huge page lock here.

Fixes: 27e1f827 ("khugepaged: enable collapse pmd for pte-mapped THP")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org>	[5.4+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021213070.27773@eggly.anvilsSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>