linux-kernel - [PATCH] Documentation: x86: fix thread

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Message-Id: <1605018060-11571-1-git-send-email-cainiao666999@gmail.com>
Date:   Tue, 10 Nov 2020 22:21:00 +0800
From:   Yang Mingzhe <cainiao666999@...il.com>
To:     tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, hpa@...or.com,
        corbet@....net
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org,
        linux-doc@...r.kernel.org, Yang Mingzhe <cainiao666999@...il.com>
Subject: [PATCH] Documentation: x86: fix thread_info's position

The bottom of the stack is where the first item was added to the stack,
usually at the zero offset. Actually, the thread_info structure at the
end of the stack.

Please see attached picture:
https://github.com/Mutated1994/kernel-beginner/blob/master/kernel-stack.md

See commits c65eacb ("sched/core: Allow putting thread_info into
task_struct"), 15f4eae ("x86: Move thread_info into task_struct")
and 883d50f ("scripts/gdb: fix get_thread_info").

Signed-off-by: Yang Mingzhe <cainiao666999@...il.com>
---
 Documentation/x86/kernel-stacks.rst | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Documentation/x86/kernel-stacks.rst b/Documentation/x86/kernel-stacks.rst
index 6b0bcf0..b88b9e12 100644
--- a/Documentation/x86/kernel-stacks.rst
+++ b/Documentation/x86/kernel-stacks.rst
@@ -15,7 +15,9 @@ Like all other architectures, x86_64 has a kernel stack for every
 active thread.  These thread stacks are THREAD_SIZE (2*PAGE_SIZE) big.
 These stacks contain useful data as long as a thread is alive or a
 zombie. While the thread is in user space the kernel stack is empty
-except for the thread_info structure at the bottom.
+except for the thread_info structure at the end (since kernel 4.9, the
+thread_info has been moved into task_struct, no longer locates at the
+end of kernel stack).
 
 In addition to the per thread stacks, there are specialized stacks
 associated with each CPU.  These stacks are only used while the kernel
-- 
1.8.3.1