[PATCH] Documentation: update kernel stack for x86_64

["晏艳(采苓)" <yanyan.yan@antgroup.com>]

Commit 6538b8ea886e ("x86_64: expand kernel stack to 16K")
expanded kernel stack for x86_64 but left the wrong documentation,
update it.

Signed-off-by: Yan Yan <yanyan.yan@antgroup.com>
---
 Documentation/x86/kernel-stacks.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/x86/kernel-stacks.rst b/Documentation/x86/kernel-stacks.rst
index 6b0bcf027ff1..738671a4070b 100644
--- a/Documentation/x86/kernel-stacks.rst
+++ b/Documentation/x86/kernel-stacks.rst
@@ -12,7 +12,7 @@ Most of the text from Keith Owens, hacked by AK
 x86_64 page size (PAGE_SIZE) is 4K.
 
 Like all other architectures, x86_64 has a kernel stack for every
-active thread.  These thread stacks are THREAD_SIZE (2*PAGE_SIZE) big.
+active thread.  These thread stacks are THREAD_SIZE (4*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.
-- 
2.32.0.3.g01195cf9f