This is a note to let you know that I've just added the patch titled usb: dwc3: debugfs: Add and remove endpoint dirs dynamically to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: usb-dwc3-debugfs-add-and-remove-endpoint-dirs-dynamically.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 8d396bb0a5b62b326f6be7594d8bd46b088296bd Mon Sep 17 00:00:00 2001 From: Jack Pham <jackp@xxxxxxxxxxxxxx> Date: Sat, 29 May 2021 12:29:32 -0700 Subject: usb: dwc3: debugfs: Add and remove endpoint dirs dynamically From: Jack Pham <jackp@xxxxxxxxxxxxxx> commit 8d396bb0a5b62b326f6be7594d8bd46b088296bd upstream. The DWC3 DebugFS directory and files are currently created once during probe. This includes creation of subdirectories for each of the gadget's endpoints. This works fine for peripheral-only controllers, as dwc3_core_init_mode() calls dwc3_gadget_init() just prior to calling dwc3_debugfs_init(). However, for dual-role controllers, dwc3_core_init_mode() will instead call dwc3_drd_init() which is problematic in a few ways. First, the initial state must be determined, then dwc3_set_mode() will have to schedule drd_work and by then dwc3_debugfs_init() could have already been invoked. Even if the initial mode is peripheral, dwc3_gadget_init() happens after the DebugFS files are created, and worse so if the initial state is host and the controller switches to peripheral much later. And secondly, even if the gadget endpoints' debug entries were successfully created, if the controller exits peripheral mode, its dwc3_eps are freed so the debug files would now hold stale references. So it is best if the DebugFS endpoint entries are created and removed dynamically at the same time the underlying dwc3_eps are. Do this by calling dwc3_debugfs_create_endpoint_dir() as each endpoint is created, and conversely remove the DebugFS entry when the endpoint is freed. Fixes: 41ce1456e1db ("usb: dwc3: core: make dwc3_set_mode() work properly") Cc: stable <stable@xxxxxxxxxxxxxxx> Reviewed-by: Peter Chen <peter.chen@xxxxxxxxxx> Signed-off-by: Jack Pham <jackp@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210529192932.22912-1-jackp@xxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/dwc3/debug.h | 3 +++ drivers/usb/dwc3/debugfs.c | 21 ++------------------- drivers/usb/dwc3/gadget.c | 3 +++ 3 files changed, 8 insertions(+), 19 deletions(-) --- a/drivers/usb/dwc3/debug.h +++ b/drivers/usb/dwc3/debug.h @@ -653,9 +653,12 @@ 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_init(struct dwc3 *); extern void dwc3_debugfs_exit(struct dwc3 *); #else +static inline void dwc3_debugfs_create_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 @@ -725,30 +725,14 @@ static void dwc3_debugfs_create_endpoint } } -static void dwc3_debugfs_create_endpoint_dir(struct dwc3_ep *dep, - struct dentry *parent) +void dwc3_debugfs_create_endpoint_dir(struct dwc3_ep *dep) { struct dentry *dir; - dir = debugfs_create_dir(dep->name, parent); + dir = debugfs_create_dir(dep->name, dep->dwc->root); dwc3_debugfs_create_endpoint_files(dep, dir); } -static void dwc3_debugfs_create_endpoint_dirs(struct dwc3 *dwc, - struct dentry *parent) -{ - int i; - - for (i = 0; i < dwc->num_eps; i++) { - struct dwc3_ep *dep = dwc->eps[i]; - - if (!dep) - continue; - - dwc3_debugfs_create_endpoint_dir(dep, parent); - } -} - void dwc3_debugfs_init(struct dwc3 *dwc) { struct dentry *root; @@ -777,7 +761,6 @@ void dwc3_debugfs_init(struct dwc3 *dwc) &dwc3_testmode_fops); debugfs_create_file("link_state", S_IRUGO | S_IWUSR, root, dwc, &dwc3_link_state_fops); - dwc3_debugfs_create_endpoint_dirs(dwc, root); } } --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -2255,6 +2255,8 @@ static int dwc3_gadget_init_endpoint(str INIT_LIST_HEAD(&dep->started_list); INIT_LIST_HEAD(&dep->cancelled_list); + dwc3_debugfs_create_endpoint_dir(dep); + return 0; } @@ -2298,6 +2300,7 @@ static void dwc3_gadget_free_endpoints(s list_del(&dep->endpoint.ep_list); } + debugfs_remove_recursive(debugfs_lookup(dep->name, dwc->root)); kfree(dep); } } Patches currently in stable-queue which might be from jackp@xxxxxxxxxxxxxx are queue-4.19/usb-dwc3-debugfs-add-and-remove-endpoint-dirs-dynamically.patch queue-4.19/usb-dwc3-core-fix-kernel-panic-when-do-reboot.patch