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arm64: mm: pass original fault address to handle_mm_fault() in PER_VMA_LOCK block

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When reading the arm64's PER_VMA_LOCK support code, I found a bit
difference between arm64 and other arch when calling handle_mm_fault()
during VMA lock-based page fault handling: the fault address is masked
before passing to handle_mm_fault(). This is also different from the
usage in mmap_lock-based handling. I think we need to pass the
original fault address to handle_mm_fault() as we did in
commit 84c5e23edecd ("arm64: mm: Pass original fault address to
handle_mm_fault()").

If we go through the code path further, we can find that the "masked"
fault address can cause mismatched fault address between perf sw
major/minor page fault sw event and perf page fault sw event:

do_page_fault
  perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, ..., addr)   // orig addr
  handle_mm_fault
    mm_account_fault
      perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, ...) // masked addr

Fixes: cd7f176aea5f ("arm64/mm: try VMA lock-based page fault handling first")
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20230524131305.2808-1-jszhang@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Jisheng Zhang 2023-05-24 21:13:05 +08:00 committed by Will Deacon
parent f3c3762178
commit 0e2aba6948
1 changed files with 1 additions and 2 deletions
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3
arch/arm64/mm/fault.c
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@ -600,8 +600,7 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
vma_end_read(vma);
goto lock_mmap;
}
fault = handle_mm_fault(vma, addr & PAGE_MASK,
mm_flags | FAULT_FLAG_VMA_LOCK, regs);
fault = handle_mm_fault(vma, addr, mm_flags | FAULT_FLAG_VMA_LOCK, regs);
vma_end_read(vma);
if (!(fault & VM_FAULT_RETRY)) {