Re: [PATCH] arm64: mm: pass original fault address to handle_mm_fault() in PER_VMA_LOCK block
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2023-05-25 17:04:09
Also in:
lkml
On Wed, May 24, 2023 at 09:13:05PM +0800, Jisheng Zhang wrote:
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>Acked-by: Catalin Marinas <catalin.marinas@arm.com> _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel