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authorJakub Kicinski <kuba@kernel.org>2020-07-10 03:42:44 +0300
committerDavid S. Miller <davem@davemloft.net>2020-07-10 23:54:00 +0300
commita2b992c828f7651db369ba8f0eb0818d70232636 (patch)
treef66e1c6eeb40d7acf38ad802e80df4efdde2e2f3 /Documentation/filesystems
parent8fb49c0109f47e4a25e8ba36abd8381afbfa7a08 (diff)
downloadlinux-a2b992c828f7651db369ba8f0eb0818d70232636.tar.xz
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>
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/debugfs.rst12
1 files changed, 8 insertions, 4 deletions
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::