From be308d68785b205e483b3a0c61ba3a82da468f2c Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Thu, 2 Feb 2023 16:28:20 +0100
Subject: [PATCH] USB: dwc3: fix memory leak with using debugfs_lookup()
Git-commit: be308d68785b205e483b3a0c61ba3a82da468f2c
References: git-fixes
Patch-mainline: v6.3-rc1

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@unisoc.com>
Reported-by: Cixi Geng <cixi.geng1@unisoc.com>
Tested-by: Cixi Geng <gengcixi@gmail.com>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/20230202152820.2409908-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/usb/dwc3/core.h    |    1 +
 drivers/usb/dwc3/debug.h   |    3 +++
 drivers/usb/dwc3/debugfs.c |   19 ++++++++-----------
 drivers/usb/dwc3/gadget.c  |    4 +---
 4 files changed, 13 insertions(+), 14 deletions(-)

--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1290,6 +1290,7 @@ struct dwc3 {
 	unsigned		async_callbacks:1;
 
 	u16			imod_interval;
+	struct dentry		*debug_root;
 };
 
 #define INCRX_BURST_MODE 0
--- a/drivers/usb/dwc3/debug.h
+++ b/drivers/usb/dwc3/debug.h
@@ -414,11 +414,14 @@ static inline const char *dwc3_gadget_ge
 
 #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)
--- a/drivers/usb/dwc3/debugfs.c
+++ b/drivers/usb/dwc3/debugfs.c
@@ -873,27 +873,23 @@ static const struct dwc3_ep_file_map dwc
 	{ "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);
 }
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2896,9 +2896,7 @@ static void dwc3_gadget_free_endpoints(s
 			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);
 	}
 }