It can be useful to the interpreter to know which flags are in use.

For instance, knowing if the preserve-argv[0] is in use would
allow to skip the pathname argument.

This patch uses an unused auxiliary vector, AT_FLAGS, to add a
flag to inform interpreter if the preserve-argv[0] is enabled.

Note by Helge Deller:
The real-world user of this patch is qemu-user, which needs to know
if it has to preserve the argv[0]. See Debian bug #970460.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: YunQiang Su <ysu@wavecomp.com>
URL: http://bugs.debian.org/970460


Signed-off-by: Helge Deller <deller@gmx.de>

On parisc a spinlock is stored in the next page behind the pgd which
protects against parallel accesses to the pgd. That's why one additional
page (PGD_ALLOC_ORDER) is allocated for the pgd.

Matthew Wilcox suggested that we instead should use a pointer in the
struct page table for this spinlock and noted, that the comments for the
PGD_ORDER and PMD_ORDER defines were wrong.

Both suggestions are addressed with this patch. Instead of having an own
spinlock to protect the pgd, we now switch to use the existing
page_table_lock.  Additionally, beside loading the pgd into cr25 in
switch_mm_irqs_off(), the physical address of this lock is loaded into
cr28 (tr4), so that we can avoid implementing a complicated lookup in
assembly for this lock in the TLB fault handlers.

The existing Hybrid L2/L3 page table scheme (where the pmd is adjacent
to the pgd) has been dropped with this patch.

Remove the locking in set_pte() and the huge-page pte functions too.
They trigger a spinlock recursion on 32bit machines and seem unnecessary.

Suggested-by: Matthew Wilcox <willy@infradead.org>
Fixes: b37d1c18 ("parisc: Use per-pagetable spinlock")
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

Use test_tsk_thread_flag() directly instead of test_ti_thread_flag() to
improve readability when the argument type is struct task_struct, it is
similar with commit 5afc7855 ("arm64: Use test_tsk_thread_flag() for
checking TIF_SINGLESTEP").

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Helge Deller <deller@gmx.de>

Bump 64-bit IRQ stack size to 64 KB.

I had a kernel IRQ stack overflow on the mx3210 debian buildd machine.  This patch increases the
64-bit IRQ stack size to 64 KB.  The 64-bit stack size needs to be larger than the 32-bit stack
size since registers are twice as big.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

On my C8000 a HPMC was triggered, but the HPMC handler wasn't called.
I got the following chassis codes:

<Cpu2> e800009802e00000  0000000000000000  CC_ERR_CHECK_HPMC
<Cpu3> e800009803e00000  00000000001b28a3  CC_ERR_CHECK_HPMC
<Cpu2> 37000f7302e00000  8400000000800000  CC_ERR_CPU_CHECK_SUMMARY
<Cpu3> 37000f7303e00000  8400000000800000  CC_ERR_CPU_CHECK_SUMMARY
<Cpu2> f600105e02e00000  fffffff0f0c00000  CC_MC_HPMC_MONARCH_SELECTED
<Cpu3> 5600100b03e00000  00000000000001a0  CC_MC_OS_HPMC_LEN_ERR
<Cpu2> 140003b202e00000  000000000000000b  CC_ERR_HPMC_STATE_ENTRY
<Cpu3> 5600106403e00000  fffffff0f043ad20  CC_MC_BR_TO_OS_HPMC_FAILED
<Cpu3> 160012cf03e00000  030001001e000007  CC_MPS_CPU_WAITING
<Cpu2> 5600100b02e00000  00000000000001a0  CC_MC_OS_HPMC_LEN_ERR
<Cpu2> 5600106402e00000  fffffff0f0438e70  CC_MC_BR_TO_OS_HPMC_FAILED
<Cpu2> e800009802e00000  0000000000000000  CC_ERR_CHECK_HPMC
<Cpu2> 37000f7302e00000  8400000000800000  CC_ERR_CPU_CHECK_SUMMARY
<Cpu2> 4000109f02e00000  0000000000000000  CC_MC_HPMC_INITIATED
<Cpu2> 4000101902e00000  0000000000000000  CC_MC_MULTIPLE_HPMCS
<Cpu2> 030010d502e00000  0000000000000000  CC_CPU_STOP

C8000 PDC is complaining about our HPMC handler length, which is 1a0 (second
part of the chassis code). Changing that to 0 makes the error go away:

<Cpu0> e800009800e00000  0000000000000000  CC_ERR_CHECK_HPMC
<Cpu3> e800009803e00000  0000000000000000  CC_ERR_CHECK_HPMC
<Cpu1> e800009801e00000  0000000000000000  CC_ERR_CHECK_HPMC
<Cpu2> e800009802e00000  0000000000000000  CC_ERR_CHECK_HPMC
<Cpu0> 37000f7300e00000  8060004000000000  CC_ERR_CPU_CHECK_SUMMARY
<Cpu3> 37000f7303e00000  8060004000000000  CC_ERR_CPU_CHECK_SUMMARY
<Cpu1> 37000f7301e00000  8060004000000000  CC_ERR_CPU_CHECK_SUMMARY
<Cpu2> 37000f7302e00000  8060004000000000  CC_ERR_CPU_CHECK_SUMMARY
<Cpu0> f600105e00e00000  fffffff0f0c00000  CC_MC_HPMC_MONARCH_SELECTED
<Cpu3> 5600109b03e00000  00000000001eb024  CC_MC_BR_TO_OS_HPMC
<Cpu1> 5600109b01e00000  00000000001eb024  CC_MC_BR_TO_OS_HPMC
<Cpu2> 5600109b02e00000  00000000001eb024  CC_MC_BR_TO_OS_HPMC
<Cpu0> 140003b200e00000  000000000000000b  CC_ERR_HPMC_STATE_ENTRY
<Cpu3> 0000000003000000  0000000000000000
<Cpu1> 0000000001000000  0000000000000000
<Cpu2> 0000000002000000  0000000000000000
<Cpu0> 5600109b00e00000  00000000001eb024  CC_MC_BR_TO_OS_HPMC
<Cpu0> 0000000000000000  0000000000000000

So at least the HPMC handler is now called, but it hangs. Which isn't really
suprising, as the code has at least one comment saying it can't handle multiple
CPUs, and here the handler is called on all CPUs. And i'm not sure whether it
can handle 64 Bit.

So despite what the PDC spec says, C8000 and RP34xx/RP44xx don't want the
OS_HPMC length in the vector set, which is odd. I disassembled the firmware and
it actually looks like a Bug in PDC.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

Pull libnvdimm fixes from Dan Williams:
 "A fix for a crash scenario that has been present since the initial
  merge, a minor regression in sysfs attribute visibility, and a fix for
  some flexible array warnings.

  The bulk of this pull is an update to the libnvdimm unit test
  infrastructure to test non-ACPI platforms. Given there is zero
  regression risk for test updates, and the tests enable validation of
  bits headed towards the next merge window, I saw no reason to hold the
  new tests back. Santosh originally submitted this before the v5.11
  window opened.

  Summary:

   - Fix a crash when sysfs accesses race 'dimm' driver probe/remove.

   - Fix a regression in 'resource' attribute visibility necessary for
     mapping badblocks and other physical address interrogations.

   - Fix some flexible array warnings

   - Expand the unit test infrastructure for non-ACPI platforms"

* tag 'libnvdimm-fixes-5.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  libnvdimm/dimm: Avoid race between probe and available_slots_show()
  ndtest: Add papr health related flags
  ndtest: Add nvdimm control functions
  ndtest: Add regions and mappings to the test buses
  ndtest: Add dimm attributes
  ndtest: Add dimms to the two buses
  ndtest: Add compatability string to treat it as PAPR family
  testing/nvdimm: Add test module for non-nfit platforms
  libnvdimm/namespace: Fix visibility of namespace resource attribute
  libnvdimm/pmem: Remove unused header
  ACPI: NFIT: Fix flexible_array.cocci warnings

Pull dma-mapping fix from Christoph Hellwig:
 "Fix a 32 vs 64-bit padding issue in the new benchmark code (Barry
  Song)"

* tag 'dma-mapping-5.11-2' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: benchmark: use u8 for reserved field in uAPI structure

Pull irq fixes from Borislav Petkov:

 - Prevent device managed IRQ allocation helpers from returning IRQ 0

 - A fix for MSI activation of PCI endpoints with multiple MSIs

* tag 'irq_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Prevent [devm_]irq_alloc_desc from returning irq 0
  genirq/msi: Activate Multi-MSI early when MSI_FLAG_ACTIVATE_EARLY is set

Pull syscall entry fixes from Borislav Petkov:

 - For syscall user dispatch, separate prctl operation from syscall
   redirection range specification before the API has been made official
   in 5.11.

 - Ensure tasks using the generic syscall code do trap after returning
   from a syscall when single-stepping is requested.

* tag 'core_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  entry: Use different define for selector variable in SUD
  entry: Ensure trap after single-step on system call return

Pull scheduler fix from Borislav Petkov:
 "Revert an attempt to not spread IRQ threads on isolated CPUs which has
  a bunch of problems"

* tag 'sched_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "lib: Restrict cpumask_local_spread to houskeeping CPUs"

Pull timer fixes from Borislav Petkov:
 "Two more timers-related fixes for v5.11:

   - Use a freezable workqueue for RTC sync because the sync can happen
     at any time and trigger suspend assertion checks in the i2c
     subsystem.

   - Correct a previous RTC validation change to check only bit 6 in
     register D because some Intel machines use bits 0-5"

* tag 'timers_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  ntp: Use freezable workqueue for RTC synchronization
  rtc: mc146818: Dont test for bit 0-5 in Register D

Pull x86 fixes from Borislav Petkov:
 "I hope this is the last batch of x86/urgent updates for this round:

   - Remove superfluous EFI PGD range checks which lead to those
     assertions failing with certain kernel configs and LLVM.

   - Disable setting breakpoints on facilities involved in #DB exception
     handling to avoid infinite loops.

   - Add extra serialization to non-serializing MSRs (IA32_TSC_DEADLINE
     and x2 APIC MSRs) to adhere to SDM's recommendation and avoid any
     theoretical issues.

   - Re-add the EPB MSR reading on turbostat so that it works on older
     kernels which don't have the corresponding EPB sysfs file.

   - Add Alder Lake to the list of CPUs which support split lock.

   - Fix %dr6 register handling in order to be able to set watchpoints
     with gdb again.

   - Disable CET instrumentation in the kernel so that gcc doesn't add
     ENDBR64 to kernel code and thus confuse tracing"

* tag 'x86_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/efi: Remove EFI PGD build time checks
  x86/debug: Prevent data breakpoints on cpu_dr7
  x86/debug: Prevent data breakpoints on __per_cpu_offset
  x86/apic: Add extra serialization for non-serializing MSRs
  tools/power/turbostat: Fallback to an MSR read for EPB
  x86/split_lock: Enable the split lock feature on another Alder Lake CPU
  x86/debug: Fix DR6 handling
  x86/build: Disable CET instrumentation in the kernel

Merge tag 'kbuild-fixes-v5.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - Use the 'python3' command to invoke python scripts because some
   distributions do not provide the 'python' command any more.

 - Clean-up and update documents

 - Use pkg-config to search libcrypto

 - Fix duplicated debug flags

 - Ignore some more stubs in scripts/kallsyms.c

* tag 'kbuild-fixes-v5.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kallsyms: fix nonconverging kallsyms table with lld
  kbuild: fix duplicated flags in DEBUG_CFLAGS
  scripts/clang-tools: switch explicitly to Python 3
  kbuild: remove PYTHON variable
  Documentation/llvm: Add a section about supported architectures
  Revert "checkpatch: add check for keyword 'boolean' in Kconfig definitions"
  scripts: use pkg-config to locate libcrypto
  kconfig: mconf: fix HOSTCC call
  doc: gcc-plugins: update gcc-plugins.rst
  kbuild: simplify GCC_PLUGINS enablement in dummy-tools/gcc
  Documentation/Kbuild: Remove references to gcc-plugin.sh
  scripts: switch explicitly to Python 3

Pull cifs fixes from Steve French:
 "Three small smb3 fixes for stable"

* tag '5.11-rc6-smb3' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: report error instead of invalid when revalidating a dentry fails
  smb3: fix crediting for compounding when only one request in flight
  smb3: Fix out-of-bounds bug in SMB2_negotiate()

Pull RISC-V fixes from Palmer Dabbelt:
 "A handful of fixes for this week:

   - A fix to avoid evalating the VA twice in virt_addr_valid, which
     fixes some WARNs under DEBUG_VIRTUAL.

   - Two fixes related to STRICT_KERNEL_RWX: one that fixes some
     permissions when strict is disabled, and one to fix some alignment
     issues when strict is enabled.

   - A fix to disallow the selection of MAXPHYSMEM_2GB on RV32, which
     isn't valid any more but may still show up in some oldconfigs.

  We still have the HiFive Unleashed ethernet phy reset regression, so
  there will likely be something coming next week"

* tag 'riscv-for-linus-5.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  RISC-V: Define MAXPHYSMEM_1GB only for RV32
  riscv: Align on L1_CACHE_BYTES when STRICT_KERNEL_RWX
  RISC-V: Fix .init section permission update
  riscv: virt_addr_valid must check the address belongs to linear mapping

Pull powerpc fixes from Michael Ellerman:

 - A fix for a change we made to __kernel_sigtramp_rt64() which confused
   glibc's backtrace logic, and also changed the semantics of that
   symbol, which was arguably an ABI break.

 - A fix for a stack overwrite in our VSX instruction emulation.

 - A couple of fixes for the Makefile logic in the new C VDSO.

Thanks to Masahiro Yamada, Naveen N.  Rao, Raoni Fassina Firmino, and
Ravi Bangoria.

* tag 'powerpc-5.11-7' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64/signal: Fix regression in __kernel_sigtramp_rt64() semantics
  powerpc/vdso64: remove meaningless vgettimeofday.o build rule
  powerpc/vdso: fix unnecessary rebuilds of vgettimeofday.o
  powerpc/sstep: Fix array out of bound warning

Pull ARM fixes from Russell King:

 - Fix latent bug with DC21285 (Footbridge PCI bridge) configuration
   accessors that affects GCC >= 4.9.2

 - Fix misplaced tegra_uart_config in decompressor

 - Ensure signal page contents are initialised

 - Fix kexec oops

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: kexec: fix oops after TLB are invalidated
  ARM: ensure the signal page contains defined contents
  ARM: 9043/1: tegra: Fix misplaced tegra_uart_config in decompressor
  ARM: footbridge: fix dc21285 PCI configuration accessors

Pull USB fixes from Greg KH:
 "Here are some small, last-minute, USB driver fixes for 5.11-rc7

  They all resolve issues reported, or are a few new device ids for some
  drivers. They include:

   - new device ids for some usb-serial drivers

   - xhci fixes for a variety of reported problems

   - dwc3 driver bugfixes

   - dwc2 driver bugfixes

   - usblp driver bugfix

   - thunderbolt bugfix

   - few other tiny fixes

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

* tag 'usb-5.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: dwc2: Fix endpoint direction check in ep_from_windex
  usb: dwc3: fix clock issue during resume in OTG mode
  xhci: fix bounce buffer usage for non-sg list case
  usb: host: xhci: mvebu: make USB 3.0 PHY optional for Armada 3720
  usb: xhci-mtk: break loop when find the endpoint to drop
  usb: xhci-mtk: skip dropping bandwidth of unchecked endpoints
  usb: renesas_usbhs: Clear pipe running flag in usbhs_pkt_pop()
  USB: gadget: legacy: fix an error code in eth_bind()
  thunderbolt: Fix possible NULL pointer dereference in tb_acpi_add_link()
  USB: serial: option: Adding support for Cinterion MV31
  usb: xhci-mtk: fix unreleased bandwidth data
  usb: gadget: aspeed: add missing of_node_put
  USB: usblp: don't call usb_set_interface if there's a single alt
  USB: serial: cp210x: add pid/vid for WSDA-200-USB
  USB: serial: cp210x: add new VID/PID for supporting Teraoka AD2000

Pull input fixes from Dmitry Torokhov:
 "Nothing terribly interesting, just a few fixups"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: xpad - sync supported devices with fork on GitHub
  Input: ariel-pwrbutton - remove unused variable ariel_pwrbutton_id_table
  Input: goodix - add support for Goodix GT9286 chip
  dt-bindings: input: touchscreen: goodix: Add binding for GT9286 IC
  dt-bindings: input: adc-keys: clarify description
  Input: ili210x - implement pressure reporting for ILI251x
  Input: i8042 - unbreak Pegatron C15B
  Input: st1232 - wait until device is ready before reading resolution
  Input: st1232 - do not read more bytes than needed
  Input: st1232 - fix off-by-one error in resolution handling

Pull SCSI fix from James Bottomley:
 "One fix in drivers (lpfc) that stops an oops on resource exhaustion"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: lpfc: Fix EEH encountering oops with NVMe traffic

Pull block fixes from Jens Axboe:
 "A few small regression fixes:

   - NVMe pull request from Christoph:
       - more quirks for buggy devices (Thorsten Leemhuis, Claus Stovgaard)
       - update the email address for Keith (Keith Busch)
       - fix an out of bounds access in nvmet-tcp (Sagi Grimberg)

   - Regression fix for BFQ shallow depth calculations introduced in
     this merge window (Lin)"

* tag 'block-5.11-2021-02-05' of git://git.kernel.dk/linux-block:
  nvmet-tcp: fix out-of-bounds access when receiving multiple h2cdata PDUs
  bfq-iosched: Revert "bfq: Fix computation of shallow depth"
  update the email address for Keith Bush
  nvme-pci: ignore the subsysem NQN on Phison E16
  nvme-pci: avoid the deepest sleep state on Kingston A2000 SSDs

Pull io_uring fixes from Jens Axboe:
 "Two small fixes that should go into 5.11:

   - task_work resource drop fix (Pavel)

   - identity COW fix (Xiaoguang)"

* tag 'io_uring-5.11-2021-02-05' of git://git.kernel.dk/linux-block:
  io_uring: drop mm/files between task_work_submit
  io_uring: don't modify identity's files uncess identity is cowed

With CONFIG_X86_5LEVEL, CONFIG_UBSAN and CONFIG_UBSAN_UNSIGNED_OVERFLOW
enabled, clang fails the build with

  x86_64-linux-ld: arch/x86/platform/efi/efi_64.o: in function `efi_sync_low_kernel_mappings':
  efi_64.c:(.text+0x22c): undefined reference to `__compiletime_assert_354'

which happens due to -fsanitize=unsigned-integer-overflow being enabled:

  -fsanitize=unsigned-integer-overflow: Unsigned integer overflow, where
  the result of an unsigned integer computation cannot be represented
  in its type. Unlike signed integer overflow, this is not undefined
  behavior, but it is often unintentional. This sanitizer does not check
  for lossy implicit conversions performed before such a computation
  (see -fsanitize=implicit-conversion).

and that fires when the (intentional) EFI_VA_START/END defines overflow
an unsigned long, leading to the assertion expressions not getting
optimized away (on GCC they do)...

However, those checks are superfluous: the runtime services mapping
code already makes sure the ranges don't overshoot EFI_VA_END as the
EFI mapping range is hardcoded. On each runtime services call, it is
switched to the EFI-specific PGD and even if mappings manage to escape
that last PGD, this won't remain unnoticed for long.

So rip them out.

See https://github.com/ClangBuiltLinux/linux/issues/256

 for more info.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: http://lkml.kernel.org/r/20210107223424.4135538-1-arnd@kernel.org

Michael Kerrisk suggested that, from an API perspective, it is a bad
idea to share the PR_SYS_DISPATCH_ defines between the prctl operation
and the selector variable.

Therefore, define two new constants to be used by SUD's selector variable
and update the corresponding documentation and test cases.

While this changes the API syscall user dispatch has never been part of a
Linux release, it will show up for the first time in 5.11.

Suggested-by: Michael Kerrisk (man-pages) <mtk.manpages@gmail.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210205184321.2062251-1-krisman@collabora.com

Commit 29915524 ("entry: Drop usage of TIF flags in the generic syscall
code") introduced a bug on architectures using the generic syscall entry
code, in which processes stopped by PTRACE_SYSCALL do not trap on syscall
return after receiving a TIF_SINGLESTEP.

The reason is that the meaning of TIF_SINGLESTEP flag is overloaded to
cause the trap after a system call is executed, but since the above commit,
the syscall call handler only checks for the SYSCALL_WORK flags on the exit
work.

Split the meaning of TIF_SINGLESTEP such that it only means single-step
mode, and create a new type of SYSCALL_WORK to request a trap immediately
after a syscall in single-step mode.  In the current implementation, the
SYSCALL_WORK flag shadows the TIF_SINGLESTEP flag for simplicity.

Update x86 to flip this bit when a tracer enables single stepping.

Fixes: 29915524 ("entry: Drop usage of TIF flags in the generic syscall code")
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Kyle Huey <me@kylehuey.com>
Link: https://lore.kernel.org/r/87h7mtc9pr.fsf_-_@collabora.com

This reverts commit 1abdfe70.

This change is broken and not solving any problem it claims to solve.

Robin reported that cpumask_local_spread() now returns any cpu out of
cpu_possible_mask in case that NOHZ_FULL is disabled (runtime or compile
time). It can also return any offline or not-present CPU in the
housekeeping mask. Before that it was returning a CPU out of
online_cpu_mask.

While the function is racy against CPU hotplug if the caller does not
protect against it, the actual use cases are not caring much about it as
they use it mostly as hint for:

 - the user space affinity hint which is unused by the kernel
 - memory node selection which is just suboptimal
 - network queue affinity which might fail but is handled gracefully

But the occasional fail vs. hotplug is very different from returning
anything from possible_cpu_mask which can have a large amount of offline
CPUs obviously.

The changelog of th...

Merge misc fixes from Andrew Morton:
 "18 patches.

  Subsystems affected by this patch series: mm (hugetlb, compaction,
  vmalloc, shmem, memblock, pagecache, kasan, and hugetlb), mailmap,
  gcov, ubsan, and MAINTAINERS"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  MAINTAINERS/.mailmap: use my @kernel.org address
  mm: hugetlb: fix missing put_page in gather_surplus_pages()
  ubsan: implement __ubsan_handle_alignment_assumption
  kasan: make addr_has_metadata() return true for valid addresses
  kasan: add explicit preconditions to kasan_report()
  mm/filemap: add missing mem_cgroup_uncharge() to __add_to_page_cache_locked()
  mailmap: add entries for Manivannan Sadhasivam
  mailmap: fix name/email for Viresh Kumar
  memblock: do not start bottom-up allocations with kernel_end
  mm: thp: fix MADV_REMOVE deadlock on shmem THP
  init/gcov: allow CONFIG_CONSTRUCTORS on UML to fix module gcov
  mm/vmalloc: separate put pages and flush VM flags
  mm, compaction: move high_pfn to the for loop scope
  mm: migrate: do not migrate HugeTLB page whose refcount is one
  mm: hugetlb: remove VM_BUG_ON_PAGE from page_huge_active
  mm: hugetlb: fix a race between isolating and freeing page
  mm: hugetlb: fix a race between freeing and dissolving the page
  mm: hugetlbfs: fix cannot migrate the fallocated HugeTLB page

Since commit a85a6c86 ("driver core: platform: Clarify that IRQ 0
is invalid"), having a linux-irq with number 0 will trigger a WARN()
when calling platform_get_irq*() to retrieve that linux-irq.

Since [devm_]irq_alloc_desc allocs a single irq and since irq 0 is not used
on some systems, it can return 0, triggering that WARN(). This happens
e.g. on Intel Bay Trail and Cherry Trail devices using the LPE audio engine
for HDMI audio:

 0 is an invalid IRQ number
 WARNING: CPU: 3 PID: 472 at drivers/base/platform.c:238 platform_get_irq_optional+0x108/0x180
 Modules linked in: snd_hdmi_lpe_audio(+) ...

 Call Trace:
  platform_get_irq+0x17/0x30
  hdmi_lpe_audio_probe+0x4a/0x6c0 [snd_hdmi_lpe_audio]

 ---[ end trace ceece38854223a0b ]---

Change the 'from' parameter passed to __[devm_]irq_alloc_descs() by the
[devm_]irq_alloc_desc macros from 0 to 1, so that these macros will no
longer return 0.

Fixes: a85a6c86 ("driver core: platform: Clarify that IRQ 0 is invalid")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20201221185647.226146-1-hdegoede@redhat.com

Assuming
- //HOST/a is mounted on /mnt
- //HOST/b is mounted on /mnt/b

On a slow connection, running 'df' and killing it while it's
processing /mnt/b can make cifs_get_inode_info() returns -ERESTARTSYS.

This triggers the following chain of events:
=> the dentry revalidation fail
=> dentry is put and released
=> superblock associated with the dentry is put
=> /mnt/b is unmounted

This patch makes cifs_d_revalidate() return the error instead of 0
(invalid) when cifs_revalidate_dentry() fails, except for ENOENT (file
deleted) and ESTALE (file recreated).

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Suggested-by: Shyam Prasad N <nspmangalore@gmail.com>
Reviewed-by: Shyam Prasad N <nspmangalore@gmail.com>
CC: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>

local_db_save() is called at the start of exc_debug_kernel(), reads DR7 and
disables breakpoints to prevent recursion.

When running in a guest (X86_FEATURE_HYPERVISOR), local_db_save() reads the
per-cpu variable cpu_dr7 to check whether a breakpoint is active or not
before it accesses DR7.

A data breakpoint on cpu_dr7 therefore results in infinite #DB recursion.

Disallow data breakpoints on cpu_dr7 to prevent that.

Fixes: 84b6a349("x86/entry: Optimize local_db_save() for virt")
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210204152708.21308-2-jiangshanlai@gmail.com

When FSGSBASE is enabled, paranoid_entry() fetches the per-CPU GSBASE value
via __per_cpu_offset or pcpu_unit_offsets.

When a data breakpoint is set on __per_cpu_offset[cpu] (read-write
operation), the specific CPU will be stuck in an infinite #DB loop.

RCU will try to send an NMI to the specific CPU, but it is not working
either since NMI also relies on paranoid_entry(). Which means it's
undebuggable.

Fixes: eaad9812("x86/entry/64: Introduce the FIND_PERCPU_BASE macro")
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210204152708.21308-1-jiangshanlai@gmail.com

Use my @kernel.org for all points of contact so that I am always
accessible.

Link: https://lkml.kernel.org/r/20210126212730.2097108-1-nathan@kernel.org


Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The VM_BUG_ON_PAGE avoids the generation of any code, even if that
expression has side-effects when !CONFIG_DEBUG_VM.

Link: https://lkml.kernel.org/r/20210126031009.96266-1-songmuchun@bytedance.com


Fixes: e5dfaceb ("mm/hugetlb.c: just use put_page_testzero() instead of page_count()")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When building ARCH=mips 32r2el_defconfig with CONFIG_UBSAN_ALIGNMENT:

  ld.lld: error: undefined symbol: __ubsan_handle_alignment_assumption
     referenced by slab.h:557 (include/linux/slab.h:557)
                   main.o:(do_initcalls) in archive init/built-in.a
     referenced by slab.h:448 (include/linux/slab.h:448)
                   do_mounts_rd.o:(rd_load_image) in archive init/built-in.a
     referenced by slab.h:448 (include/linux/slab.h:448)
                   do_mounts_rd.o:(identify_ramdisk_image) in archive init/built-in.a
     referenced 1579 more times

Implement this for the kernel based on LLVM's
handleAlignmentAssumptionImpl because the kernel is not linked against
the compiler runtime.

Link: https://github.com/ClangBuiltLinux/linux/issues/1245
Link: https://github.com/llvm/llvm-project/blob/llvmorg-11.0.1/compiler-rt/lib/ubsan/ubsan_handlers.cpp#L151-L190
Link: https://lkml.kernel.org/r/20210127224451.2587372-1-nathan@kernel.org


Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Currently, addr_has_metadata() returns true for every address.  An
invalid address (e.g.  NULL) passed to the function when, KASAN_HW_TAGS
is enabled, leads to a kernel panic.

Make addr_has_metadata() return true for valid addresses only.

Note: KASAN_HW_TAGS support for vmalloc will be added with a future
patch.

Link: https://lkml.kernel.org/r/20210126134409.47894-3-vincenzo.frascino@arm.com


Fixes: 2e903b91 ("kasan, arm64: implement HW_TAGS runtime")
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Leon Romanovsky <leonro@mellanox.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "kasan: Fix metadata detection for KASAN_HW_TAGS", v5.

With the introduction of KASAN_HW_TAGS, kasan_report() currently assumes
that every location in memory has valid metadata associated.  This is
due to the fact that addr_has_metadata() returns always true.

As a consequence of this, an invalid address (e.g.  NULL pointer
address) passed to kasan_report() when KASAN_HW_TAGS is enabled, leads
to a kernel panic.

Example below, based on arm64:

   BUG: KASAN: invalid-access in 0x0
   Read at addr 0000000000000000 by task swapper/0/1
   Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
   Mem abort info:
     ESR = 0x96000004
     EC = 0x25: DABT (current EL), IL = 32 bits
     SET = 0, FnV = 0
     EA = 0, S1PTW = 0
   Data abort info:
     ISV = 0, ISS = 0x00000004
     CM = 0, WnR = 0

  ...

   Call trace:
    mte_get_mem_tag+0x24/0x40
    kasan_report+0x1a4/0x410
    alsa_sound_last_init+0x8c/0xa4
    do_one_initcall+0x50/0x1b0
    kernel_init_freeable+0x1d4/0x23c
    kernel_init+0x14/0x118
    ret_from_fork+0x10/0x34
   Code: d65f03c0 9000f021 f9428021 b6cfff61 (d9600000)
   ---[ end trace 377c8bb45bdd3a1a ]---
   hrtimer: interrupt took 48694256 ns
   note: swapper/0[1] exited with preempt_count 1
   Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
   SMP: stopping secondary CPUs
   Kernel Offset: 0x35abaf140000 from 0xffff800010000000
   PHYS_OFFSET: 0x40000000
   CPU features: 0x0a7e0152,61c0a030
   Memory Limit: none
   ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]---

This series fixes the behavior of addr_has_metadata() that now returns
true only when the address is valid.

This patch (of 2):

With the introduction of KASAN_HW_TAGS, kasan_report() accesses the
metadata only when addr_has_metadata() succeeds.

Add a comment to make sure that the preconditions to the function are
explicitly clarified.

Link: https://lkml.kernel.org/r/20210126134409.47894-1-vincenzo.frascino@arm.com
Link: https://lkml.kernel.org/r/20210126134409.47894-2-vincenzo.frascino@arm.com


Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Leon Romanovsky <leonro@mellanox.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 3fea5a49 ("mm: memcontrol: convert page cache to a new
mem_cgroup_charge() API") introduced a bug in __add_to_page_cache_locked()
causing the following splat:

  page dumped because: VM_BUG_ON_PAGE(page_memcg(page))
  pages's memcg:ffff8889a4116000
  ------------[ cut here ]------------
  kernel BUG at mm/memcontrol.c:2924!
  invalid opcode: 0000 [#1] SMP KASAN PTI
  CPU: 35 PID: 12345 Comm: cat Tainted: G S      W I       5.11.0-rc4-debug+ #1
  Hardware name: HP HP Z8 G4 Workstation/81C7, BIOS P60 v01.25 12/06/2017
  RIP: commit_charge+0xf4/0x130
  Call Trace:
    mem_cgroup_charge+0x175/0x770
    __add_to_page_cache_locked+0x712/0xad0
    add_to_page_cache_lru+0xc5/0x1f0
    cachefiles_read_or_alloc_pages+0x895/0x2e10 [cachefiles]
    __fscache_read_or_alloc_pages+0x6c0/0xa00 [fscache]
    __nfs_readpages_from_fscache+0x16d/0x630 [nfs]
    nfs_readpages+0x24e/0x540 [nfs]
    read_pages+0x5b1/0xc40
    page_cache_ra_unbounded+0x460/0x750
    generic_file_buffered_read_get_pages+0x290/0x1710
    generic_file_buffered_read+0x2a9/0xc30
    nfs_file_read+0x13f/0x230 [nfs]
    new_sync_read+0x3af/0x610
    vfs_read+0x339/0x4b0
    ksys_read+0xf1/0x1c0
    do_syscall_64+0x33/0x40
    entry_SYSCALL_64_after_hwframe+0x44/0xa9

Before that commit, there was a try_charge() and commit_charge() in
__add_to_page_cache_locked().  These two separated charge functions were
replaced by a single mem_cgroup_charge().  However, it forgot to add a
matching mem_cgroup_uncharge() when the xarray insertion failed with the
page released back to the pool.

Fix this by adding a mem_cgroup_uncharge() call when insertion error
happens.

Link: https://lkml.kernel.org/r/20210125042441.20030-1-longman@redhat.com


Fixes: 3fea5a49 ("mm: memcontrol: convert page cache to a new mem_cgroup_charge() API")
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <smuchun@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>