From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- drivers/usb/gadget/epautoconf.c | 214 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 214 insertions(+) create mode 100644 drivers/usb/gadget/epautoconf.c (limited to 'drivers/usb/gadget/epautoconf.c') diff --git a/drivers/usb/gadget/epautoconf.c b/drivers/usb/gadget/epautoconf.c new file mode 100644 index 000000000..30016b805 --- /dev/null +++ b/drivers/usb/gadget/epautoconf.c @@ -0,0 +1,214 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * epautoconf.c -- endpoint autoconfiguration for usb gadget drivers + * + * Copyright (C) 2004 David Brownell + */ + +#include +#include +#include +#include + +#include +#include + +#include +#include + +/** + * usb_ep_autoconfig_ss() - choose an endpoint matching the ep + * descriptor and ep companion descriptor + * @gadget: The device to which the endpoint must belong. + * @desc: Endpoint descriptor, with endpoint direction and transfer mode + * initialized. For periodic transfers, the maximum packet + * size must also be initialized. This is modified on + * success. + * @ep_comp: Endpoint companion descriptor, with the required + * number of streams. Will be modified when the chosen EP + * supports a different number of streams. + * + * This routine replaces the usb_ep_autoconfig when needed + * superspeed enhancments. If such enhancemnets are required, + * the FD should call usb_ep_autoconfig_ss directly and provide + * the additional ep_comp parameter. + * + * By choosing an endpoint to use with the specified descriptor, + * this routine simplifies writing gadget drivers that work with + * multiple USB device controllers. The endpoint would be + * passed later to usb_ep_enable(), along with some descriptor. + * + * That second descriptor won't always be the same as the first one. + * For example, isochronous endpoints can be autoconfigured for high + * bandwidth, and then used in several lower bandwidth altsettings. + * Also, high and full speed descriptors will be different. + * + * Be sure to examine and test the results of autoconfiguration + * on your hardware. This code may not make the best choices + * about how to use the USB controller, and it can't know all + * the restrictions that may apply. Some combinations of driver + * and hardware won't be able to autoconfigure. + * + * On success, this returns an claimed usb_ep, and modifies the endpoint + * descriptor bEndpointAddress. For bulk endpoints, the wMaxPacket value + * is initialized as if the endpoint were used at full speed and + * the bmAttribute field in the ep companion descriptor is + * updated with the assigned number of streams if it is + * different from the original value. To prevent the endpoint + * from being returned by a later autoconfig call, claims it by + * assigning ep->claimed to true. + * + * On failure, this returns a null endpoint descriptor. + */ +struct usb_ep *usb_ep_autoconfig_ss( + struct usb_gadget *gadget, + struct usb_endpoint_descriptor *desc, + struct usb_ss_ep_comp_descriptor *ep_comp +) +{ + struct usb_ep *ep; + + if (gadget->ops->match_ep) { + ep = gadget->ops->match_ep(gadget, desc, ep_comp); + if (ep) + goto found_ep; + } + + /* Second, look at endpoints until an unclaimed one looks usable */ + list_for_each_entry (ep, &gadget->ep_list, ep_list) { + if (usb_gadget_ep_match_desc(gadget, ep, desc, ep_comp)) + goto found_ep; + } + + /* Fail */ + return NULL; +found_ep: + + /* + * If the protocol driver hasn't yet decided on wMaxPacketSize + * and wants to know the maximum possible, provide the info. + */ + if (desc->wMaxPacketSize == 0) + desc->wMaxPacketSize = cpu_to_le16(ep->maxpacket_limit); + + /* report address */ + desc->bEndpointAddress &= USB_DIR_IN; + if (isdigit(ep->name[2])) { + u8 num = simple_strtoul(&ep->name[2], NULL, 10); + desc->bEndpointAddress |= num; + } else if (desc->bEndpointAddress & USB_DIR_IN) { + if (++gadget->in_epnum > 15) + return NULL; + desc->bEndpointAddress = USB_DIR_IN | gadget->in_epnum; + } else { + if (++gadget->out_epnum > 15) + return NULL; + desc->bEndpointAddress |= gadget->out_epnum; + } + + ep->address = desc->bEndpointAddress; + ep->desc = NULL; + ep->comp_desc = NULL; + ep->claimed = true; + return ep; +} +EXPORT_SYMBOL_GPL(usb_ep_autoconfig_ss); + +/** + * usb_ep_autoconfig() - choose an endpoint matching the + * descriptor + * @gadget: The device to which the endpoint must belong. + * @desc: Endpoint descriptor, with endpoint direction and transfer mode + * initialized. For periodic transfers, the maximum packet + * size must also be initialized. This is modified on success. + * + * By choosing an endpoint to use with the specified descriptor, this + * routine simplifies writing gadget drivers that work with multiple + * USB device controllers. The endpoint would be passed later to + * usb_ep_enable(), along with some descriptor. + * + * That second descriptor won't always be the same as the first one. + * For example, isochronous endpoints can be autoconfigured for high + * bandwidth, and then used in several lower bandwidth altsettings. + * Also, high and full speed descriptors will be different. + * + * Be sure to examine and test the results of autoconfiguration on your + * hardware. This code may not make the best choices about how to use the + * USB controller, and it can't know all the restrictions that may apply. + * Some combinations of driver and hardware won't be able to autoconfigure. + * + * On success, this returns an claimed usb_ep, and modifies the endpoint + * descriptor bEndpointAddress. For bulk endpoints, the wMaxPacket value + * is initialized as if the endpoint were used at full speed. Because of + * that the users must consider adjusting the autoconfigured descriptor. + * To prevent the endpoint from being returned by a later autoconfig call, + * claims it by assigning ep->claimed to true. + * + * On failure, this returns a null endpoint descriptor. + */ +struct usb_ep *usb_ep_autoconfig( + struct usb_gadget *gadget, + struct usb_endpoint_descriptor *desc +) +{ + struct usb_ep *ep; + u8 type; + + ep = usb_ep_autoconfig_ss(gadget, desc, NULL); + if (!ep) + return NULL; + + type = usb_endpoint_type(desc); + + /* report (variable) full speed bulk maxpacket */ + if (type == USB_ENDPOINT_XFER_BULK) { + int size = ep->maxpacket_limit; + + /* min() doesn't work on bitfields with gcc-3.5 */ + if (size > 64) + size = 64; + desc->wMaxPacketSize = cpu_to_le16(size); + } + + return ep; +} +EXPORT_SYMBOL_GPL(usb_ep_autoconfig); + +/** + * usb_ep_autoconfig_release - releases endpoint and set it to initial state + * @ep: endpoint which should be released + * + * This function can be used during function bind for endpoints obtained + * from usb_ep_autoconfig(). It unclaims endpoint claimed by + * usb_ep_autoconfig() to make it available for other functions. Endpoint + * which was released is no longer valid and shouldn't be used in + * context of function which released it. + */ +void usb_ep_autoconfig_release(struct usb_ep *ep) +{ + ep->claimed = false; + ep->driver_data = NULL; +} +EXPORT_SYMBOL_GPL(usb_ep_autoconfig_release); + +/** + * usb_ep_autoconfig_reset - reset endpoint autoconfig state + * @gadget: device for which autoconfig state will be reset + * + * Use this for devices where one configuration may need to assign + * endpoint resources very differently from the next one. It clears + * state such as ep->claimed and the record of assigned endpoints + * used by usb_ep_autoconfig(). + */ +void usb_ep_autoconfig_reset (struct usb_gadget *gadget) +{ + struct usb_ep *ep; + + list_for_each_entry (ep, &gadget->ep_list, ep_list) { + ep->claimed = false; + ep->driver_data = NULL; + } + gadget->in_epnum = 0; + gadget->out_epnum = 0; +} +EXPORT_SYMBOL_GPL(usb_ep_autoconfig_reset); -- cgit v1.3.1