From a2b992c828f7651db369ba8f0eb0818d70232636 Mon Sep 17 00:00:00 2001
From: Jakub Kicinski <kuba@kernel.org>
Date: Thu, 9 Jul 2020 17:42:44 -0700
Subject: debugfs: make sure we can remove u32_array files cleanly
debugfs_create_u32_array() allocates a small structure to wrap
the data and size information about the array. If users ever
try to remove the file this leads to a leak since nothing ever
frees this wrapper.
That said there are no upstream users of debugfs_create_u32_array()
that'd remove a u32 array file (we only have one u32 array user in
CMA), so there is no real bug here.
Make callers pass a wrapper they allocated. This way the lifetime
management of the wrapper is on the caller, and we can avoid the
potential leak in debugfs.
CC: Chucheng Luo <luochucheng@vivo.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
Documentation/filesystems/debugfs.rst | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
(limited to 'Documentation')
diff --git a/Documentation/filesystems/debugfs.rst b/Documentation/filesystems/debugfs.rst
index 1da7a4b7383d..728ab57a611a 100644
--- a/Documentation/filesystems/debugfs.rst
+++ b/Documentation/filesystems/debugfs.rst
@@ -185,13 +185,17 @@ byte offsets over a base for the register block.
If you want to dump an u32 array in debugfs, you can create file with::
+ struct debugfs_u32_array {
+ u32 *array;
+ u32 n_elements;
+ };
+
void debugfs_create_u32_array(const char *name, umode_t mode,
struct dentry *parent,
- u32 *array, u32 elements);
+ struct debugfs_u32_array *array);
-The "array" argument provides data, and the "elements" argument is
-the number of elements in the array. Note: Once array is created its
-size can not be changed.
+The "array" argument wraps a pointer to the array's data and the number
+of its elements. Note: Once array is created its size can not be changed.
There is a helper function to create device related seq_file::
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