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

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Message-Id: <20180322052336.1001-1-joel@jms.id.au>
Date:   Thu, 22 Mar 2018 15:53:36 +1030
From:   Joel Stanley <joel@....id.au>
To:     Jonathan Corbet <corbet@....net>, "Tobin C . Harding" <me@...in.cc>
Cc:     Michael Ellerman <mpe@...erman.id.au>, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] Documentation: Mention why %p prints ptrval

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.
 
 Symbols/Function Pointers
 -------------------------
-- 
2.15.1