linux-stable.git/arch/powerpc/include, branch v5.13.2 Linux kernel stable tree powerpc/64s/interrupt: preserve regs->softe for NMI interrupts 2021-07-14T15:07:46+00:00 Nicholas Piggin npiggin@gmail.com 2021-06-30T07:46:17+00:00 13a4d6ea398e74cd858d90ec7ca5a08bc4b6c3cd [ Upstream commit 1b0482229c302a3c6afd00d6b3bf0169cf279b44 ] If an NMI interrupt hits in an implicit soft-masked region, regs->softe is modified to reflect that. This may not be necessary for correctness at the moment, but it is less surprising and it's unhelpful when debugging or adding checks. Make sure this is changed back to how it was found before returning. Fixes: 4ec5feec1ad0 ("powerpc/64s: Make NMI record implicitly soft-masked code as irqs disabled") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210630074621.2109197-6-npiggin@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 1b0482229c302a3c6afd00d6b3bf0169cf279b44 ]

If an NMI interrupt hits in an implicit soft-masked region, regs->softe
is modified to reflect that. This may not be necessary for correctness
at the moment, but it is less surprising and it's unhelpful when
debugging or adding checks.

Make sure this is changed back to how it was found before returning.

Fixes: 4ec5feec1ad0 ("powerpc/64s: Make NMI record implicitly soft-masked code as irqs disabled")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210630074621.2109197-6-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
powerpc: Fix is_kvm_guest() / kvm_para_available() 2021-07-14T15:07:45+00:00 Michael Ellerman mpe@ellerman.id.au 2021-06-23T13:05:14+00:00 1a09a37887720ddb41303c8c408c1d8e65d5c9c5 [ Upstream commit 95839225639ba7c3d8d7231b542728dcf222bf2d ] Commit a21d1becaa3f ("powerpc: Reintroduce is_kvm_guest() as a fast-path check") added is_kvm_guest() and changed kvm_para_available() to use it. is_kvm_guest() checks a static key, kvm_guest, and that static key is set in check_kvm_guest(). The problem is check_kvm_guest() is only called on pseries, and even then only in some configurations. That means is_kvm_guest() always returns false on all non-pseries and some pseries depending on configuration. That's a bug. For PR KVM guests this is noticable because they no longer do live patching of themselves, which can be detected by the omission of a message in dmesg such as: KVM: Live patching for a fast VM worked To fix it make check_kvm_guest() an initcall, to ensure it's always called at boot. It needs to be core so that it runs before kvm_guest_init() which is postcore. To be an initcall it needs to return int, where 0 means success, so update that. We still call it manually in pSeries_smp_probe(), because that runs before init calls are run. Fixes: a21d1becaa3f ("powerpc: Reintroduce is_kvm_guest() as a fast-path check") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210623130514.2543232-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 95839225639ba7c3d8d7231b542728dcf222bf2d ]

Commit a21d1becaa3f ("powerpc: Reintroduce is_kvm_guest() as a fast-path
check") added is_kvm_guest() and changed kvm_para_available() to use it.

is_kvm_guest() checks a static key, kvm_guest, and that static key is
set in check_kvm_guest().

The problem is check_kvm_guest() is only called on pseries, and even
then only in some configurations. That means is_kvm_guest() always
returns false on all non-pseries and some pseries depending on
configuration. That's a bug.

For PR KVM guests this is noticable because they no longer do live
patching of themselves, which can be detected by the omission of a
message in dmesg such as:

  KVM: Live patching for a fast VM worked

To fix it make check_kvm_guest() an initcall, to ensure it's always
called at boot. It needs to be core so that it runs before
kvm_guest_init() which is postcore. To be an initcall it needs to return
int, where 0 means success, so update that.

We still call it manually in pSeries_smp_probe(), because that runs
before init calls are run.

Fixes: a21d1becaa3f ("powerpc: Reintroduce is_kvm_guest() as a fast-path check")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210623130514.2543232-1-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
KVM: PPC: Book3S HV: Fix TLB management on SMT8 POWER9 and POWER10 processors 2021-07-14T15:06:27+00:00 Suraj Jitindar Singh sjitindarsingh@gmail.com 2021-06-02T04:04:41+00:00 3c9cb03aa19f51d4d0f9c59e3ced86080faeaa24 [ Upstream commit 77bbbc0cf84834ed130838f7ac1988567f4d0288 ] The POWER9 vCPU TLB management code assumes all threads in a core share a TLB, and that TLBIEL execued by one thread will invalidate TLBs for all threads. This is not the case for SMT8 capable POWER9 and POWER10 (big core) processors, where the TLB is split between groups of threads. This results in TLB multi-hits, random data corruption, etc. Fix this by introducing cpu_first_tlb_thread_sibling etc., to determine which siblings share TLBs, and use that in the guest TLB flushing code. [npiggin@gmail.com: add changelog and comment] Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210602040441.3984352-1-npiggin@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 77bbbc0cf84834ed130838f7ac1988567f4d0288 ]

The POWER9 vCPU TLB management code assumes all threads in a core share
a TLB, and that TLBIEL execued by one thread will invalidate TLBs for
all threads. This is not the case for SMT8 capable POWER9 and POWER10
(big core) processors, where the TLB is split between groups of threads.
This results in TLB multi-hits, random data corruption, etc.

Fix this by introducing cpu_first_tlb_thread_sibling etc., to determine
which siblings share TLBs, and use that in the guest TLB flushing code.

[npiggin@gmail.com: add changelog and comment]

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210602040441.3984352-1-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Merge tag 'powerpc-5.13-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux 2021-06-19T23:50:23+00:00 Linus Torvalds torvalds@linux-foundation.org 2021-06-19T23:50:23+00:00 b84a7c286cecf0604a5f8bd5dfcd5e1ca7233e15 Pull powerpc fixes from Michael Ellerman: "Fix initrd corruption caused by our recent change to use relative jump labels. Fix a crash using perf record on systems without a hardware PMU backend. Rework our 64-bit signal handling slighty to make it more closely match the old behaviour, after the recent change to use unsafe user accessors. Thanks to Anastasia Kovaleva, Athira Rajeev, Christophe Leroy, Daniel Axtens, Greg Kurz, and Roman Bolshakov" * tag 'powerpc-5.13-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/perf: Fix crash in perf_instruction_pointer() when ppmu is not set powerpc: Fix initrd corruption with relative jump labels powerpc/signal64: Copy siginfo before changing regs->nip powerpc/mem: Add back missing header to fix 'no previous prototype' error 
Pull powerpc fixes from Michael Ellerman:
 "Fix initrd corruption caused by our recent change to use relative jump
  labels.

  Fix a crash using perf record on systems without a hardware PMU
  backend.

  Rework our 64-bit signal handling slighty to make it more closely
  match the old behaviour, after the recent change to use unsafe user
  accessors.

  Thanks to Anastasia Kovaleva, Athira Rajeev, Christophe Leroy, Daniel
  Axtens, Greg Kurz, and Roman Bolshakov"

* tag 'powerpc-5.13-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/perf: Fix crash in perf_instruction_pointer() when ppmu is not set
  powerpc: Fix initrd corruption with relative jump labels
  powerpc/signal64: Copy siginfo before changing regs->nip
  powerpc/mem: Add back missing header to fix 'no previous prototype' error
powerpc: Fix initrd corruption with relative jump labels 2021-06-15T13:35:57+00:00 Michael Ellerman mpe@ellerman.id.au 2021-06-14T13:14:40+00:00 478036c4cd1a16e613a2f883d79c03cf187faacb Commit b0b3b2c78ec0 ("powerpc: Switch to relative jump labels") switched us to using relative jump labels. That involves changing the code, target and key members in struct jump_entry to be relative to the address of the jump_entry, rather than absolute addresses. We have two static inlines that create a struct jump_entry, arch_static_branch() and arch_static_branch_jump(), as well as an asm macro ARCH_STATIC_BRANCH, which is used by the pseries-only hypervisor tracing code. Unfortunately we missed updating the key to be a relative reference in ARCH_STATIC_BRANCH. That causes a pseries kernel to have a handful of jump_entry structs with bad key values. Instead of being a relative reference they instead hold the full address of the key. However the code doesn't expect that, it still adds the key value to the address of the jump_entry (see jump_entry_key()) expecting to get a pointer to a key somewhere in kernel data. The table of jump_entry structs sits in rodata, which comes after the kernel text. In a typical build this will be somewhere around 15MB. The address of the key will be somewhere in data, typically around 20MB. Adding the two values together gets us a pointer somewhere around 45MB. We then call static_key_set_entries() with that bad pointer and modify some members of the struct static_key we think we are pointing at. A pseries kernel is typically ~30MB in size, so writing to ~45MB won't corrupt the kernel itself. However if we're booting with an initrd, depending on the size and exact location of the initrd, we can corrupt the initrd. Depending on how exactly we corrupt the initrd it can either cause the system to not boot, or just corrupt one of the files in the initrd. The fix is simply to make the key value relative to the jump_entry struct in the ARCH_STATIC_BRANCH macro. Fixes: b0b3b2c78ec0 ("powerpc: Switch to relative jump labels") Reported-by: Anastasia Kovaleva <a.kovaleva@yadro.com> Reported-by: Roman Bolshakov <r.bolshakov@yadro.com> Reported-by: Greg Kurz <groug@kaod.org> Reported-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Tested-by: Daniel Axtens <dja@axtens.net> Tested-by: Greg Kurz <groug@kaod.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210614131440.312360-1-mpe@ellerman.id.au 
Commit b0b3b2c78ec0 ("powerpc: Switch to relative jump labels") switched
us to using relative jump labels. That involves changing the code,
target and key members in struct jump_entry to be relative to the
address of the jump_entry, rather than absolute addresses.

We have two static inlines that create a struct jump_entry,
arch_static_branch() and arch_static_branch_jump(), as well as an asm
macro ARCH_STATIC_BRANCH, which is used by the pseries-only hypervisor
tracing code.

Unfortunately we missed updating the key to be a relative reference in
ARCH_STATIC_BRANCH.

That causes a pseries kernel to have a handful of jump_entry structs
with bad key values. Instead of being a relative reference they instead
hold the full address of the key.

However the code doesn't expect that, it still adds the key value to the
address of the jump_entry (see jump_entry_key()) expecting to get a
pointer to a key somewhere in kernel data.

The table of jump_entry structs sits in rodata, which comes after the
kernel text. In a typical build this will be somewhere around 15MB. The
address of the key will be somewhere in data, typically around 20MB.
Adding the two values together gets us a pointer somewhere around 45MB.

We then call static_key_set_entries() with that bad pointer and modify
some members of the struct static_key we think we are pointing at.

A pseries kernel is typically ~30MB in size, so writing to ~45MB won't
corrupt the kernel itself. However if we're booting with an initrd,
depending on the size and exact location of the initrd, we can corrupt
the initrd. Depending on how exactly we corrupt the initrd it can either
cause the system to not boot, or just corrupt one of the files in the
initrd.

The fix is simply to make the key value relative to the jump_entry
struct in the ARCH_STATIC_BRANCH macro.

Fixes: b0b3b2c78ec0 ("powerpc: Switch to relative jump labels")
Reported-by: Anastasia Kovaleva <a.kovaleva@yadro.com>
Reported-by: Roman Bolshakov <r.bolshakov@yadro.com>
Reported-by: Greg Kurz <groug@kaod.org>
Reported-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Daniel Axtens <dja@axtens.net>
Tested-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210614131440.312360-1-mpe@ellerman.id.au
Merge tag 'powerpc-5.13-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux 2021-06-06T19:39:36+00:00 Linus Torvalds torvalds@linux-foundation.org 2021-06-06T19:39:36+00:00 bd7b12aa6081c3755b693755d608f58e13798a60 Pull powerpc fixes from Michael Ellerman: "Fix our KVM reverse map real-mode handling since we enabled huge vmalloc (in some configurations). Revert a recent change to our IOMMU code which broke some devices. Fix KVM handling of FSCR on P7/P8, which could have possibly let a guest crash it's Qemu. Fix kprobes validation of prefixed instructions across page boundary. Thanks to Alexey Kardashevskiy, Christophe Leroy, Fabiano Rosas, Frederic Barrat, Naveen N. Rao, and Nicholas Piggin" * tag 'powerpc-5.13-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: Revert "powerpc/kernel/iommu: Align size for IOMMU_PAGE_SIZE() to save TCEs" KVM: PPC: Book3S HV: Save host FSCR in the P7/8 path powerpc: Fix reverse map real-mode address lookup with huge vmalloc powerpc/kprobes: Fix validation of prefixed instructions across page boundary 
Pull powerpc fixes from Michael Ellerman:
 "Fix our KVM reverse map real-mode handling since we enabled huge
  vmalloc (in some configurations).

  Revert a recent change to our IOMMU code which broke some devices.

  Fix KVM handling of FSCR on P7/P8, which could have possibly let a
  guest crash it's Qemu.

  Fix kprobes validation of prefixed instructions across page boundary.

  Thanks to Alexey Kardashevskiy, Christophe Leroy, Fabiano Rosas,
  Frederic Barrat, Naveen N. Rao, and Nicholas Piggin"

* tag 'powerpc-5.13-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  Revert "powerpc/kernel/iommu: Align size for IOMMU_PAGE_SIZE() to save TCEs"
  KVM: PPC: Book3S HV: Save host FSCR in the P7/8 path
  powerpc: Fix reverse map real-mode address lookup with huge vmalloc
  powerpc/kprobes: Fix validation of prefixed instructions across page boundary
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2021-05-29T16:02:25+00:00 Linus Torvalds torvalds@linux-foundation.org 2021-05-29T16:02:25+00:00 224478289ca0e7abf06a3bc63b06c42a2bf84c69 Pull KVM fixes from Paolo Bonzini: "ARM fixes: - Another state update on exit to userspace fix - Prevent the creation of mixed 32/64 VMs - Fix regression with irqbypass not restarting the guest on failed connect - Fix regression with debug register decoding resulting in overlapping access - Commit exception state on exit to usrspace - Fix the MMU notifier return values - Add missing 'static' qualifiers in the new host stage-2 code x86 fixes: - fix guest missed wakeup with assigned devices - fix WARN reported by syzkaller - do not use BIT() in UAPI headers - make the kvm_amd.avic parameter bool PPC fixes: - make halt polling heuristics consistent with other architectures selftests: - various fixes - new performance selftest memslot_perf_test - test UFFD minor faults in demand_paging_test" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (44 commits) selftests: kvm: fix overlapping addresses in memslot_perf_test KVM: X86: Kill off ctxt->ud KVM: X86: Fix warning caused by stale emulation context KVM: X86: Use kvm_get_linear_rip() in single-step and #DB/#BP interception KVM: x86/mmu: Fix comment mentioning skip_4k KVM: VMX: update vcpu posted-interrupt descriptor when assigning device KVM: rename KVM_REQ_PENDING_TIMER to KVM_REQ_UNBLOCK KVM: x86: add start_assignment hook to kvm_x86_ops KVM: LAPIC: Narrow the timer latency between wait_lapic_expire and world switch selftests: kvm: do only 1 memslot_perf_test run by default KVM: X86: Use _BITUL() macro in UAPI headers KVM: selftests: add shared hugetlbfs backing source type KVM: selftests: allow using UFFD minor faults for demand paging KVM: selftests: create alias mappings when using shared memory KVM: selftests: add shmem backing source type KVM: selftests: refactor vm_mem_backing_src_type flags KVM: selftests: allow different backing source types KVM: selftests: compute correct demand paging size KVM: selftests: simplify setup_demand_paging error handling KVM: selftests: Print a message if /dev/kvm is missing ... 
Pull KVM fixes from Paolo Bonzini:
 "ARM fixes:

   - Another state update on exit to userspace fix

   - Prevent the creation of mixed 32/64 VMs

   - Fix regression with irqbypass not restarting the guest on failed
     connect

   - Fix regression with debug register decoding resulting in
     overlapping access

   - Commit exception state on exit to usrspace

   - Fix the MMU notifier return values

   - Add missing 'static' qualifiers in the new host stage-2 code

  x86 fixes:

   - fix guest missed wakeup with assigned devices

   - fix WARN reported by syzkaller

   - do not use BIT() in UAPI headers

   - make the kvm_amd.avic parameter bool

  PPC fixes:

   - make halt polling heuristics consistent with other architectures

  selftests:

   - various fixes

   - new performance selftest memslot_perf_test

   - test UFFD minor faults in demand_paging_test"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (44 commits)
  selftests: kvm: fix overlapping addresses in memslot_perf_test
  KVM: X86: Kill off ctxt->ud
  KVM: X86: Fix warning caused by stale emulation context
  KVM: X86: Use kvm_get_linear_rip() in single-step and #DB/#BP interception
  KVM: x86/mmu: Fix comment mentioning skip_4k
  KVM: VMX: update vcpu posted-interrupt descriptor when assigning device
  KVM: rename KVM_REQ_PENDING_TIMER to KVM_REQ_UNBLOCK
  KVM: x86: add start_assignment hook to kvm_x86_ops
  KVM: LAPIC: Narrow the timer latency between wait_lapic_expire and world switch
  selftests: kvm: do only 1 memslot_perf_test run by default
  KVM: X86: Use _BITUL() macro in UAPI headers
  KVM: selftests: add shared hugetlbfs backing source type
  KVM: selftests: allow using UFFD minor faults for demand paging
  KVM: selftests: create alias mappings when using shared memory
  KVM: selftests: add shmem backing source type
  KVM: selftests: refactor vm_mem_backing_src_type flags
  KVM: selftests: allow different backing source types
  KVM: selftests: compute correct demand paging size
  KVM: selftests: simplify setup_demand_paging error handling
  KVM: selftests: Print a message if /dev/kvm is missing
  ...
powerpc: Fix reverse map real-mode address lookup with huge vmalloc 2021-05-28T12:54:27+00:00 Nicholas Piggin npiggin@gmail.com 2021-05-26T12:00:05+00:00 5362a4b6ee6136018558ef6b2c4701aa15ebc602 real_vmalloc_addr() does not currently work for huge vmalloc, which is what the reverse map can be allocated with for radix host, hash guest. Extract the hugepage aware equivalent from eeh code into a helper, and convert existing sites including this one to use it. Fixes: 8abddd968a30 ("powerpc/64s/radix: Enable huge vmalloc mappings") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210526120005.3432222-1-npiggin@gmail.com 
real_vmalloc_addr() does not currently work for huge vmalloc, which is
what the reverse map can be allocated with for radix host, hash guest.

Extract the hugepage aware equivalent from eeh code into a helper, and
convert existing sites including this one to use it.

Fixes: 8abddd968a30 ("powerpc/64s/radix: Enable huge vmalloc mappings")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210526120005.3432222-1-npiggin@gmail.com
KVM: rename KVM_REQ_PENDING_TIMER to KVM_REQ_UNBLOCK 2021-05-27T11:57:38+00:00 Marcelo Tosatti mtosatti@redhat.com 2021-05-25T13:41:17+00:00 084071d5e9226add45a6031928bf10e6afc855fd KVM_REQ_UNBLOCK will be used to exit a vcpu from its inner vcpu halt emulation loop. Rename KVM_REQ_PENDING_TIMER to KVM_REQ_UNBLOCK, switch PowerPC to arch specific request bit. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Message-Id: <20210525134321.303768132@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> 
KVM_REQ_UNBLOCK will be used to exit a vcpu from
its inner vcpu halt emulation loop.

Rename KVM_REQ_PENDING_TIMER to KVM_REQ_UNBLOCK, switch
PowerPC to arch specific request bit.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Message-Id: <20210525134321.303768132@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
powerpc/64s/syscall: Fix ptrace syscall info with scv syscalls 2021-05-20T14:58:56+00:00 Nicholas Piggin npiggin@gmail.com 2021-05-20T11:19:31+00:00 d72500f992849d31ebae8f821a023660ddd0dcc2 The scv implementation missed updating syscall return value and error value get/set functions to deal with the changed register ABI. This broke ptrace PTRACE_GET_SYSCALL_INFO as well as some kernel auditing and tracing functions. Fix. tools/testing/selftests/ptrace/get_syscall_info now passes when scv is used. Fixes: 7fa95f9adaee ("powerpc/64s: system call support for scv/rfscv instructions") Cc: stable@vger.kernel.org # v5.9+ Reported-by: "Dmitry V. Levin" <ldv@altlinux.org> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Dmitry V. Levin <ldv@altlinux.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210520111931.2597127-2-npiggin@gmail.com 
The scv implementation missed updating syscall return value and error
value get/set functions to deal with the changed register ABI. This
broke ptrace PTRACE_GET_SYSCALL_INFO as well as some kernel auditing
and tracing functions.

Fix. tools/testing/selftests/ptrace/get_syscall_info now passes when
scv is used.

Fixes: 7fa95f9adaee ("powerpc/64s: system call support for scv/rfscv instructions")
Cc: stable@vger.kernel.org # v5.9+
Reported-by: "Dmitry V. Levin" <ldv@altlinux.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210520111931.2597127-2-npiggin@gmail.com