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SubjectRe: [PATCH] usb: dwc3: Fix dentry leak in dwc3_gadget_free_endpoints
On Fri, Oct 28, 2022 at 04:49:19PM +0800, Cixi Geng wrote:
> From: Bruce Chen <bruce.chen@unisoc.com>
>
> When using debugfs_remove_recursive leaks a dentry with
> a hotplug stress test, the phone runs out of memory.
>
> Thus fix the issue by using the newly created debugfs_lookup_and_remove().
>
> Signed-off-by: Bruce Chen <bruce.chen@unisoc.com>
> Signed-off-by: Cixi Geng <cixi.geng1@unisoc.com>
> ---
> drivers/usb/dwc3/core.h | 1 +
> drivers/usb/dwc3/debugfs.c | 3 ++-
> drivers/usb/dwc3/gadget.c | 4 +---
> 3 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 8f9959ba9fd4..ba3ecaa7f06c 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -1261,6 +1261,7 @@ struct dwc3 {
> u8 num_eps;
>
> struct dwc3_hwparams hwparams;
> + struct dentry *root;

You forgot to document this new variable.

And name it a bit better?

> struct debugfs_regset32 *regset;
>
> u32 dbg_lsp_select;
> diff --git a/drivers/usb/dwc3/debugfs.c b/drivers/usb/dwc3/debugfs.c
> index f2b7675c7f62..b9af4a81f51d 100644
> --- a/drivers/usb/dwc3/debugfs.c
> +++ b/drivers/usb/dwc3/debugfs.c
> @@ -911,6 +911,7 @@ 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->root = root;
> debugfs_create_regset32("regdump", 0444, root, dwc->regset);
> debugfs_create_file("lsp_dump", 0644, root, dwc, &dwc3_lsp_fops);
>
> @@ -929,6 +930,6 @@ 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_remove(dwc->root);
> kfree(dwc->regset);
> }
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 079cd333632e..6d6c188fcbea 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -3172,9 +3172,7 @@ 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)));
> + debugfs_lookup_and_remove(dep->name, dwc->root);
> kfree(dep);
> }
> }
> --
> 2.34.1
>

I don't think this is the full fix.

Below is a patch that I've had in a tree that I need to push out (along
with the other 33 debugfs_lookup patches) that should resolve this for
this driver in a more complete way.

Can you try this version instead?

thanks,

greg k-h

---------------------


From 49b893792579af1bea46c5004759cb35475c4fca Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Fri, 2 Sep 2022 16:41:39 +0200
Subject: [PATCH 06/34] USB: dwc3: debugfs_lookup() fix

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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 079cd333632e..404bb7ee61a8 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -3172,9 +3172,7 @@ 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);
}
}
--
2.38.1
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