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    SubjectRe: clean up and streamline probe_kernel_* and friends v4
    On Thu, 21 May 2020 17:22:38 +0200
    Christoph Hellwig <hch@lst.de> wrote:

    > Hi all,
    >
    > this series start cleaning up the safe kernel and user memory probing
    > helpers in mm/maccess.c, and then allows architectures to implement
    > the kernel probing without overriding the address space limit and
    > temporarily allowing access to user memory. It then switches x86
    > over to this new mechanism by reusing the unsafe_* uaccess logic.
    >
    > This version also switches to the saner copy_{from,to}_kernel_nofault
    > naming suggested by Linus.
    >
    > I kept the x86 helpers as-is without calling unsage_{get,put}_user as
    > that avoids a number of hard to trace casts, and it will still work
    > with the asm-goto based version easily.
    >
    > Changes since v3:
    > - cleanup how bpf and trace_kprobe perform the TASK_SIZE checks
    > - remove the unused dst argument to probe_kernel_read_allowed
    > - document the -ERANGE return value

    This series looks good to me.

    Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>

    for this series.

    Thank you!

    >
    > Changes since v2:
    > - rebased on 5.7-rc6 with the bpf trace format string changes
    > - rename arch_kernel_read to __get_kernel_nofault and arch_kernel_write
    > to __put_kernel_nofault
    > - clean up the tracers to only allowd "mixed" reads when the kernel
    > has non-overlapping address spaces


    --
    Masami Hiramatsu <mhiramat@kernel.org>

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