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    SubjectRe: [PATCH 1/2] ramoops: use pstore interface
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    On Wed, Nov 16, 2011 at 9:35 PM, Chen Gong <gong.chen@linux.intel.com> wrote:
    > 于 2011/11/17 5:25, Kees Cook 写道:
    >> Instead of using /dev/mem directly, use the common pstore infrastructure
    >> to handle Oops gathering and extraction.
    >> [...]
    >> +       /* Explicitly only take the first part of any new crash.
    >> +        * If our buffer is larger than kmsg_bytes, this can never happen,
    >> +        * and if our buffer is smaller than kmsg_bytes, we don't want the
    >> +        * report split across multiple records. */
    >> +       if (part != 1)
    >> +               return -ENOSPC;
    >
    > why only one part is accepted? You are afraid about your filename style?

    The logic in ramoops doesn't expect to have a split-up report. Since
    pstore doesn't limit reports to kmsg_bytes in size (it actually splits
    reports on pstore_info.bufsize) this is a non-issue, but in the case
    that a platform defines very small ramoops record sizes, I didn't want
    the extra stuff written to additional records. If ramoops gains real
    record headers ever, this can change, of course. In the meantime, it
    should be defensive.

    >> +       /* Only a single ramoops area allowed at a time, so fail extra
    >> +        * probes.
    >> +        */
    >> +       if (cxt->max_count)
    >> +               goto fail3;
    >
    > Should be fail4
    > [...]
    > In some situations fail4 maybe hits max_count != 0, so here max_count should
    > be cleared. I think you should rearrange the logic in this function
    > carefully.

    Ah, thanks for the catch. All the error targets got messed up. I'll
    fix them and name them instead of using numbers.

    >> +       /* TODO(kees): It shouldn't be possible to remove ramoops since
    >> +        * pstore doesn't support unregistering yet. When it does, remove
    >> +        * this early return and add the unregister where noted below.
    >> +        */
    >> +       return -EBUSY;
    >
    > This style is not reasonable. Maybe it should have a better wrap.

    I'm not sure I understand what you mean. It's wrapped roughly to
    column 75 already. What would be better for this comment? Or did you
    mean I shouldn't have unreachable code?

    > BTW, you need to update Documentation/ramoops.txt

    Ah! Yes, thanks for the reminder.

    -Kees

    --
    Kees Cook
    ChromeOS Security
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