From 1ff77cbefe5a653ea12874c213ea4bd0d72c1067 Mon Sep 17 00:00:00 2001 From: Jiazi Liu Date: Tue, 15 Sep 2026 19:06:37 +0800 Subject: usb: dwc3: gadget: fix IRQ storm on invalid event buffer count When dwc3_check_event_buf() reads a GEVNTCOUNT value exceeding the event buffer length, commit 63ccd26cd1f6 ("usb: dwc3: gadget: check that event count does not exceed event buffer length") returns IRQ_NONE without writing back GEVNTCOUNT. Since the DWC3 interrupt is level-triggered, the uncleared IRQ source keeps the line asserted, causing a tight IRQ storm that accumulates 99,900 unhandled interrupts and triggers spurious.c:184 BUG -> kernel panic. The resulting call stack: __report_bad_irq+0xac/0xc8 note_interrupt+0x340/0x468 handle_irq_event+0xac/0xc0 handle_fasteoi_irq+0x120/0x228 gic_handle_irq+0x68/0x108 ... kernel BUG at kernel/irq/spurious.c:184 To reproduce, write a bogus value exceeding the event buffer length directly to the GEVNTCOUNT register: devmem 4 0x1004 Write the bogus count back to GEVNTCOUNT to clear the IRQ source, consistent with the stale event clearing pattern in dwc3_event_buffers_setup(), and schedule error recovery to reinitialize the controller. Fixes: 63ccd26cd1f6 ("usb: dwc3: gadget: check that event count does not exceed event buffer length") Cc: stable Suggested-by: Thinh Nguyen Signed-off-by: Jiazi Liu Link: https://patch.msgid.link/20260915110637.17658-1-jiazi.liu1984@gmail.com Acked-by: Thinh Nguyen Signed-off-by: Greg Kroah-Hartman --- drivers/usb/dwc3/core.h | 19 ++++++++ drivers/usb/dwc3/ep0.c | 9 ++++ drivers/usb/dwc3/gadget.c | 108 +++++++++++++++++++++++++++++++++++++++++++++- 3 files changed, 134 insertions(+), 2 deletions(-) (limited to 'drivers/usb') diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h index 608daeb7e..f3dabb37f 100644 --- a/drivers/usb/dwc3/core.h +++ b/drivers/usb/dwc3/core.h @@ -49,6 +49,7 @@ #define DWC3_ENDPOINTS_NUM 32 #define DWC3_XHCI_RESOURCES_NUM 2 #define DWC3_ISOC_MAX_RETRIES 5 +#define DWC3_ERR_RECOVERY_MAX 3 #define DWC3_SCRATCHBUF_SIZE 4096 /* each buffer is assumed to be 4KiB */ #define DWC3_EVENT_BUFFERS_SIZE 4096 @@ -841,6 +842,12 @@ enum dwc3_link_state { DWC3_LINK_STATE_MASK = 0x0f, }; +enum dwc3_err_state { + DWC3_ERR_NONE = 0, + DWC3_ERR_RECOVERY, + DWC3_ERR_UNRECOVERABLE, +}; + /* TRB Length, PCM and Status */ #define DWC3_TRB_SIZE_MASK (0x00ffffff) #define DWC3_TRB_SIZE_LENGTH(n) ((n) & DWC3_TRB_SIZE_MASK) @@ -1004,6 +1011,7 @@ struct dwc3_glue_ops { /** * struct dwc3 - representation of our controller * @drd_work: workqueue used for role swapping + * @err_recovery_work: workqueue used for controller error recovery * @ep0_trb: trb which is used for the ctrl_req * @bounce: address of bounce buffer * @setup_buf: used while precessing STD USB requests @@ -1013,6 +1021,7 @@ struct dwc3_glue_ops { * @ep0_in_setup: one control transfer is completed and enter setup phase * @lock: for synchronizing * @mutex: for mode switching + * @connect_mutex: for the pull-up and err_recovery_work * @dev: pointer to our struct device * @sysdev: pointer to the DMA-capable device * @xhci: pointer to our xHCI child @@ -1079,6 +1088,9 @@ struct dwc3_glue_ops { * @ep0_next_event: hold the next expected event * @ep0state: state of endpoint zero * @link_state: link state + * @err_state: current error recovery state. + * @err_recovery_count: number of consecutive error recovery attempts until + * confirmed healthy and reset to 0 on reset event. * @speed: device speed (super, high, full, low) * @hwparams: copy of hwparams registers * @regset: debugfs pointer to regdump file @@ -1189,6 +1201,7 @@ struct dwc3_glue_ops { */ struct dwc3 { struct work_struct drd_work; + struct work_struct err_recovery_work; struct dwc3_trb *ep0_trb; void *bounce; u8 *setup_buf; @@ -1203,6 +1216,9 @@ struct dwc3 { /* mode switching lock */ struct mutex mutex; + /* serializes pull-up run/stop vs error recovery */ + struct mutex connect_mutex; + struct device *dev; struct device *sysdev; @@ -1332,6 +1348,9 @@ struct dwc3 { enum dwc3_ep0_next ep0_next_event; enum dwc3_ep0_state ep0state; enum dwc3_link_state link_state; + enum dwc3_err_state err_state; + + u32 err_recovery_count; u16 u2sel; u16 u2pel; diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c index 310b5ffb2..46a34c4a0 100644 --- a/drivers/usb/dwc3/ep0.c +++ b/drivers/usb/dwc3/ep0.c @@ -200,6 +200,11 @@ int dwc3_gadget_ep0_queue(struct usb_ep *ep, struct usb_request *request, int ret; spin_lock_irqsave(&dwc->lock, flags); + if (dwc->err_state != DWC3_ERR_NONE) { + ret = -ESHUTDOWN; + goto out; + } + if (!dep->endpoint.desc || !dwc->pullups_connected || !dwc->connected) { dev_err(dwc->dev, "%s: can't queue to disabled endpoint\n", dep->name); @@ -271,6 +276,10 @@ int dwc3_gadget_ep0_set_halt(struct usb_ep *ep, int value) int ret; spin_lock_irqsave(&dwc->lock, flags); + if (dwc->err_state != DWC3_ERR_NONE) { + spin_unlock_irqrestore(&dwc->lock, flags); + return -ESHUTDOWN; + } ret = __dwc3_gadget_ep0_set_halt(ep, value); spin_unlock_irqrestore(&dwc->lock, flags); diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index f245e66cd..ee8372356 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -1149,6 +1149,10 @@ static int dwc3_gadget_ep_enable(struct usb_ep *ep, return 0; spin_lock_irqsave(&dwc->lock, flags); + if (dwc->err_state != DWC3_ERR_NONE) { + spin_unlock_irqrestore(&dwc->lock, flags); + return -ESHUTDOWN; + } ret = __dwc3_gadget_ep_enable(dep, DWC3_DEPCFG_ACTION_INIT); spin_unlock_irqrestore(&dwc->lock, flags); @@ -2060,6 +2064,10 @@ static int dwc3_gadget_ep_queue(struct usb_ep *ep, struct usb_request *request, int ret; spin_lock_irqsave(&dwc->lock, flags); + if (dwc->err_state != DWC3_ERR_NONE) { + spin_unlock_irqrestore(&dwc->lock, flags); + return -ESHUTDOWN; + } ret = __dwc3_gadget_ep_queue(dep, req); spin_unlock_irqrestore(&dwc->lock, flags); @@ -2292,6 +2300,10 @@ static int dwc3_gadget_ep_set_halt(struct usb_ep *ep, int value) int ret; spin_lock_irqsave(&dwc->lock, flags); + if (dwc->err_state != DWC3_ERR_NONE) { + spin_unlock_irqrestore(&dwc->lock, flags); + return -ESHUTDOWN; + } ret = __dwc3_gadget_ep_set_halt(dep, value, false); spin_unlock_irqrestore(&dwc->lock, flags); @@ -2306,6 +2318,10 @@ static int dwc3_gadget_ep_set_wedge(struct usb_ep *ep) int ret; spin_lock_irqsave(&dwc->lock, flags); + if (dwc->err_state != DWC3_ERR_NONE) { + spin_unlock_irqrestore(&dwc->lock, flags); + return -ESHUTDOWN; + } dep->flags |= DWC3_EP_WEDGE; if (dep->number == 0 || dep->number == 1) @@ -2437,6 +2453,10 @@ static int dwc3_gadget_wakeup(struct usb_gadget *g) } spin_lock_irqsave(&dwc->lock, flags); + if (dwc->err_state != DWC3_ERR_NONE) { + spin_unlock_irqrestore(&dwc->lock, flags); + return -ESHUTDOWN; + } if (!dwc->gadget->wakeup_armed) { dev_err(dwc->dev, "not armed for remote wakeup\n"); spin_unlock_irqrestore(&dwc->lock, flags); @@ -2464,6 +2484,10 @@ static int dwc3_gadget_func_wakeup(struct usb_gadget *g, int intf_id) } spin_lock_irqsave(&dwc->lock, flags); + if (dwc->err_state != DWC3_ERR_NONE) { + spin_unlock_irqrestore(&dwc->lock, flags); + return -ESHUTDOWN; + } /* * If the link is in U3, signal for remote wakeup and wait for the * link to transition to U0 before sending device notification. @@ -2833,10 +2857,13 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on) synchronize_irq(dwc->irq_gadget); + /* Serialize against dwc3_err_recovery_work() */ + mutex_lock(&dwc->connect_mutex); if (!is_on) ret = dwc3_gadget_soft_disconnect(dwc); else ret = dwc3_gadget_soft_connect(dwc); + mutex_unlock(&dwc->connect_mutex); pm_runtime_put(dwc->dev); @@ -4153,6 +4180,10 @@ static void dwc3_gadget_reset_interrupt(struct dwc3 *dwc) dwc->suspended = false; + /* The controller is recovered. */ + if (dwc->err_state == DWC3_ERR_NONE) + dwc->err_recovery_count = 0; + /* * Ideally, dwc3_reset_gadget() would trigger the function * drivers to stop any active transfers through ep disable. @@ -4640,6 +4671,12 @@ static irqreturn_t dwc3_thread_interrupt(int irq, void *_evt) return ret; } +static void dwc3_schedule_err_recovery(struct dwc3 *dwc) +{ + dwc->err_state = DWC3_ERR_RECOVERY; + schedule_work(&dwc->err_recovery_work); +} + static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt) { struct dwc3 *dwc = evt->dwc; @@ -4673,9 +4710,21 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt) return IRQ_NONE; if (count > evt->length) { - dev_err_ratelimited(dwc->dev, "invalid count(%u) > evt->length(%u)\n", + dev_err(dwc->dev, "invalid count(%u) > evt->length(%u)\n", count, evt->length); - return IRQ_NONE; + /* + * This is a fatal error - the driver and controller are out of + * sync on which event has been consumed. Reinitializing the + * controller is required to recover. Write the bogus count back + * to GEVNTCOUNT to clear the IRQ source, consistent with the + * stale event clearing in dwc3_event_buffers_setup(), then + * schedule error recovery. + */ + spin_lock(&dwc->lock); + dwc3_schedule_err_recovery(dwc); + spin_unlock(&dwc->lock); + dwc3_writel(dwc, DWC3_GEVNTCOUNT(0), count); + return IRQ_HANDLED; } evt->count = count; @@ -4735,6 +4784,57 @@ static void dwc_gadget_release(struct device *dev) kfree(gadget); } +static void dwc3_err_recovery_work(struct work_struct *work) +{ + struct dwc3 *dwc = container_of(work, struct dwc3, err_recovery_work); + unsigned long flags; + int ret; + + /* serializes against dwc3_gadget_pullup() */ + mutex_lock(&dwc->connect_mutex); + + ret = dwc3_gadget_soft_disconnect(dwc); + + dwc3_disconnect_gadget_sleepable(dwc); + + if (ret) + goto err_unrecoverable; + + if (dwc->softconnect) { + u32 count; + /* + * Wait irq to finish before soft_connect resets evt->lpos and + * the event buffer registers to avoid racing with + * dwc3_process_event_buf(). + */ + synchronize_irq(dwc->irq_gadget); + + spin_lock_irqsave(&dwc->lock, flags); + count = ++dwc->err_recovery_count; + spin_unlock_irqrestore(&dwc->lock, flags); + + if (count > DWC3_ERR_RECOVERY_MAX) + goto err_unrecoverable; + + ret = dwc3_gadget_soft_connect(dwc); + if (ret) + goto err_unrecoverable; + } + mutex_unlock(&dwc->connect_mutex); + + spin_lock_irqsave(&dwc->lock, flags); + dwc->err_state = DWC3_ERR_NONE; + spin_unlock_irqrestore(&dwc->lock, flags); + return; + +err_unrecoverable: + dev_err(dwc->dev, "Unable to recover the controller\n"); + mutex_unlock(&dwc->connect_mutex); + spin_lock_irqsave(&dwc->lock, flags); + dwc->err_state = DWC3_ERR_UNRECOVERABLE; + spin_unlock_irqrestore(&dwc->lock, flags); +} + /** * dwc3_gadget_init - initializes gadget related registers * @dwc: pointer to our controller context structure @@ -4778,6 +4878,8 @@ int dwc3_gadget_init(struct dwc3 *dwc) } init_completion(&dwc->ep0_in_setup); + INIT_WORK(&dwc->err_recovery_work, dwc3_err_recovery_work); + mutex_init(&dwc->connect_mutex); dwc->gadget = kzalloc_obj(struct usb_gadget); if (!dwc->gadget) { ret = -ENOMEM; @@ -4874,6 +4976,8 @@ void dwc3_gadget_exit(struct dwc3 *dwc) if (!dwc->gadget) return; + cancel_work_sync(&dwc->err_recovery_work); + mutex_destroy(&dwc->connect_mutex); dwc3_enable_susphy(dwc, true); usb_del_gadget(dwc->gadget); dwc3_gadget_free_endpoints(dwc); -- cgit v1.3.1