On Thu, Feb 02, 2023, Greg Kroah-Hartman wrote:
> When calling debugfs_lookup() the result must have dput() called on it,
> otherwise the memory will leak over time. To make things simpler, just
> call debugfs_lookup_and_remove() instead which handles all of the logic
> at once.
>
> Note, the root dentry for the debugfs directory for the device needs to
> be saved so we don't have to keep looking it up, which required a bit
> more refactoring to properly create and remove it when needed.
>
> Reported-by: Bruce Chen <bruce.chen@xxxxxxxxxx>
> Reported-by: Cixi Geng <cixi.geng1@xxxxxxxxxx>
> Tested-by: Cixi Geng <gengcixi@xxxxxxxxx>
> Cc: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>
> Cc: linux-usb@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---
> drivers/usb/dwc3/core.h | 2 ++
> drivers/usb/dwc3/debug.h | 3 +++
> drivers/usb/dwc3/debugfs.c | 19 ++++++++-----------
> drivers/usb/dwc3/gadget.c | 4 +---
> 4 files changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 8f9959ba9fd4..582ebd9cf9c2 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -1117,6 +1117,7 @@ struct dwc3_scratchpad_array {
> * address.
> * @num_ep_resized: carries the current number endpoints which have had its tx
> * fifo resized.
> + * @debug_root: root debugfs directory for this device to put its files in.
> */
> struct dwc3 {
> struct work_struct drd_work;
> @@ -1332,6 +1333,7 @@ struct dwc3 {
> int max_cfg_eps;
> int last_fifo_depth;
> int num_ep_resized;
> + struct dentry *debug_root;
> };
>
> #define INCRX_BURST_MODE 0
> diff --git a/drivers/usb/dwc3/debug.h b/drivers/usb/dwc3/debug.h
> index 48b44b88dc25..8bb2c9e3b9ac 100644
> --- a/drivers/usb/dwc3/debug.h
> +++ b/drivers/usb/dwc3/debug.h
> @@ -414,11 +414,14 @@ static inline const char *dwc3_gadget_generic_cmd_status_string(int status)
>
> #ifdef CONFIG_DEBUG_FS
> extern void dwc3_debugfs_create_endpoint_dir(struct dwc3_ep *dep);
> +extern void dwc3_debugfs_remove_endpoint_dir(struct dwc3_ep *dep);
> extern void dwc3_debugfs_init(struct dwc3 *d);
> extern void dwc3_debugfs_exit(struct dwc3 *d);
> #else
> static inline void dwc3_debugfs_create_endpoint_dir(struct dwc3_ep *dep)
> { }
> +static inline void dwc3_debugfs_remove_endpoint_dir(struct dwc3_ep *dep)
> +{ }
> static inline void dwc3_debugfs_init(struct dwc3 *d)
> { }
> static inline void dwc3_debugfs_exit(struct dwc3 *d)
> diff --git a/drivers/usb/dwc3/debugfs.c b/drivers/usb/dwc3/debugfs.c
> index f2b7675c7f62..850df0e6bcab 100644
> --- a/drivers/usb/dwc3/debugfs.c
> +++ b/drivers/usb/dwc3/debugfs.c
> @@ -873,27 +873,23 @@ static const struct dwc3_ep_file_map dwc3_ep_file_map[] = {
> { "GDBGEPINFO", &dwc3_ep_info_register_fops, },
> };
>
> -static void dwc3_debugfs_create_endpoint_files(struct dwc3_ep *dep,
> - struct dentry *parent)
> +void dwc3_debugfs_create_endpoint_dir(struct dwc3_ep *dep)
> {
> + struct dentry *dir;
> int i;
>
> + dir = debugfs_create_dir(dep->name, dep->dwc->debug_root);
> for (i = 0; i < ARRAY_SIZE(dwc3_ep_file_map); i++) {
> const struct file_operations *fops = dwc3_ep_file_map[i].fops;
> const char *name = dwc3_ep_file_map[i].name;
>
> - debugfs_create_file(name, 0444, parent, dep, fops);
> + debugfs_create_file(name, 0444, dir, dep, fops);
> }
> }
>
> -void dwc3_debugfs_create_endpoint_dir(struct dwc3_ep *dep)
> +void dwc3_debugfs_remove_endpoint_dir(struct dwc3_ep *dep)
> {
> - struct dentry *dir;
> - struct dentry *root;
> -
> - root = debugfs_lookup(dev_name(dep->dwc->dev), usb_debug_root);
> - dir = debugfs_create_dir(dep->name, root);
> - dwc3_debugfs_create_endpoint_files(dep, dir);
> + debugfs_lookup_and_remove(dep->name, dep->dwc->debug_root);
> }
>
> void dwc3_debugfs_init(struct dwc3 *dwc)
> @@ -911,6 +907,7 @@ void dwc3_debugfs_init(struct dwc3 *dwc)
> dwc->regset->base = dwc->regs - DWC3_GLOBALS_REGS_START;
>
> root = debugfs_create_dir(dev_name(dwc->dev), usb_debug_root);
> + dwc->debug_root = root;
> debugfs_create_regset32("regdump", 0444, root, dwc->regset);
> debugfs_create_file("lsp_dump", 0644, root, dwc, &dwc3_lsp_fops);
>
> @@ -929,6 +926,6 @@ void dwc3_debugfs_init(struct dwc3 *dwc)
>
> void dwc3_debugfs_exit(struct dwc3 *dwc)
> {
> - debugfs_remove(debugfs_lookup(dev_name(dwc->dev), usb_debug_root));
> + debugfs_lookup_and_remove(dev_name(dwc->dev), usb_debug_root);
> kfree(dwc->regset);
> }
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 89dcfac01235..3c63fa97a680 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -3194,9 +3194,7 @@ static void dwc3_gadget_free_endpoints(struct dwc3 *dwc)
> list_del(&dep->endpoint.ep_list);
> }
>
> - debugfs_remove_recursive(debugfs_lookup(dep->name,
> - debugfs_lookup(dev_name(dep->dwc->dev),
> - usb_debug_root)));
> + dwc3_debugfs_remove_endpoint_dir(dep);
> kfree(dep);
> }
> }
> --
> 2.39.1
>
Acked-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>
Thanks,
Thinh
