Re: [RFC 02/11] mm: debug: deal with a new family of MM pointers

From: Kirill A. Shutemov
Date: Thu Apr 30 2015 - 12:17:45 EST


On Tue, Apr 14, 2015 at 04:56:24PM -0400, Sasha Levin wrote:
> This teaches our printing functions about a new family of MM pointer that it
> could now print.
>
> I've picked %pZ because %pm and %pM were already taken, so I figured it
> doesn't really matter what we go with. We also have the option of stealing
> one of those two...
>
> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
> ---
> lib/vsprintf.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index 8243e2f..809d19d 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -1375,6 +1375,16 @@ char *comm_name(char *buf, char *end, struct task_struct *tsk,
> return string(buf, end, name, spec);
> }
>
> +static noinline_for_stack
> +char *mm_pointer(char *buf, char *end, struct task_struct *tsk,
> + struct printf_spec spec, const char *fmt)
> +{
> + switch (fmt[1]) {

shouldn't we printout at least pointer address for unknown suffixes?

> + }
> +
> + return buf;
> +}
> +
> int kptr_restrict __read_mostly;
>
> /*
> @@ -1463,6 +1473,7 @@ int kptr_restrict __read_mostly;
> * (legacy clock framework) of the clock
> * - 'Cr' For a clock, it prints the current rate of the clock
> * - 'T' task_struct->comm
> + * - 'Z' Outputs a readable version of a type of memory management struct.
> *
> * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
> * function pointers are really function descriptors, which contain a
> @@ -1615,6 +1626,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
> spec, fmt);
> case 'T':
> return comm_name(buf, end, ptr, spec, fmt);
> + case 'Z':
> + return mm_pointer(buf, end, ptr, spec, fmt);
> }
> spec.flags |= SMALL;
> if (spec.field_width == -1) {
> --
> 1.7.10.4
>
> --
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--
Kirill A. Shutemov
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