Messages in this thread | | | Date | Tue, 3 Oct 2023 17:43:10 +0200 | Subject | Re: [PATCH -fixes 0/2] Fix set_huge_pte_at() | From | Alexandre Ghiti <> |
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+cc Andrew: Would you mind taking this patchset in your tree for the next rc? This patchset depends on a previous fix for arm64 that you merged in rc4 which is not in the riscv -fixes branch yet.
I saw with Palmer and he should ack this shortly.
If I can do anything else to help, let me know.
Thanks,
Alex
On 28/09/2023 17:18, Alexandre Ghiti wrote: > A recent report [1] from Ryan for arm64 revealed that we do not handle > swap entries when setting a hugepage backed by a NAPOT region (the > contpte riscv equivalent). > > As explained in [1], the issue was discovered by a new test in kselftest > which uses poison entries, but the symptoms are different from arm64 though: > > - the riscv kernel bugs because we do not handle VM_FAULT_HWPOISON*, > this is fixed by patch 1, > - after that, the test passes because the first pte_napot() fails (the > poison entry does not have the N bit set), and then we only set the > first page table entry covering the NAPOT hugepage, which is enough > for hugetlb_fault() to correctly raise a VM_FAULT_HWPOISON wherever we > write in this mapping since only this first page table entry is > checked > (see https://elixir.bootlin.com/linux/v6.6-rc3/source/mm/hugetlb.c#L6071). > But this seems fragile so patch 2 sets all page table entries of a > NAPOT mapping. > > [1]: https://lore.kernel.org/linux-arm-kernel/20230922115804.2043771-1-ryan.roberts@arm.com/ > > > Alexandre Ghiti (2): > riscv: Handle VM_FAULT_[HWPOISON|HWPOISON_LARGE] faults instead of > panicking > riscv: Fix set_huge_pte_at() for NAPOT mappings when a swap entry is > set > > arch/riscv/mm/fault.c | 2 +- > arch/riscv/mm/hugetlbpage.c | 19 +++++++++++++------ > 2 files changed, 14 insertions(+), 7 deletions(-) >
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