linux-kernel - Re: [PATCH] Documentation: Mention why %p prints ptrval

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Message-ID: <20180322201214.GE3305@eros>
Date:   Fri, 23 Mar 2018 07:12:14 +1100
From:   "Tobin C . Harding" <me@...in.cc>
To:     Joel Stanley <joel@....id.au>
Cc:     Jonathan Corbet <corbet@....net>,
        Michael Ellerman <mpe@...erman.id.au>,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Documentation: Mention why %p prints ptrval

On Thu, Mar 22, 2018 at 03:53:36PM +1030, Joel Stanley wrote:
> When debugging recent kernels, people will see '(ptrval)' but there
> isn't much information as to what that means. Briefly describe why it's
> there.
> 
> Signed-off-by: Joel Stanley <joel@....id.au>
> ---
>  Documentation/core-api/printk-formats.rst | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
> index 934559b3c130..eb30efdd2e78 100644
> --- a/Documentation/core-api/printk-formats.rst
> +++ b/Documentation/core-api/printk-formats.rst
> @@ -60,8 +60,8 @@ Plain Pointers
>  Pointers printed without a specifier extension (i.e unadorned %p) are
>  hashed to prevent leaking information about the kernel memory layout. This
>  has the added benefit of providing a unique identifier. On 64-bit machines
> -the first 32 bits are zeroed. If you *really* want the address see %px
> -below.
> +the first 32 bits are zeroed. The kernel will print ``(ptrval)`` until it
> +gathers enough entropy. If you *really* want the address see %px below.

Acked-by: Tobin C. Harding <me@...in.cc>

thanks,
Tobin.