From: Mathias Nyman Date: Thu, 15 Jan 2026 23:37:58 +0000 (+0200) Subject: xhci: sideband: don't dereference freed ring when removing sideband endpoint X-Git-Tag: v6.18.7~81 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=34f6634dba87ef72b3c3a3a524be663adef7ab42;p=thirdparty%2Fkernel%2Fstable.git xhci: sideband: don't dereference freed ring when removing sideband endpoint commit dd83dc1249737b837ac5d57c81f2b0977c613d9f upstream. xhci_sideband_remove_endpoint() incorrecly assumes that the endpoint is running and has a valid transfer ring. Lianqin reported a crash during suspend/wake-up stress testing, and found the cause to be dereferencing a non-existing transfer ring 'ep->ring' during xhci_sideband_remove_endpoint(). The endpoint and its ring may be in unknown state if this function is called after xHCI was reinitialized in resume (lost power), or if device is being re-enumerated, disconnected or endpoint already dropped. Fix this by both removing unnecessary ring access, and by checking ep->ring exists before dereferencing it. Also make sure endpoint is running before attempting to stop it. Remove the xhci_initialize_ring_info() call during sideband endpoint removal as is it only initializes ring structure enqueue, dequeue and cycle state values to their starting values without changing actual hardware enqueue, dequeue and cycle state. Leaving them out of sync is worse than leaving it as it is. The endpoint will get freed in after this in most usecases. If the (audio) class driver want's to reuse the endpoint after offload then it is up to the class driver to ensure endpoint is properly set up. Reported-by: 胡连勤 Closes: https://lore.kernel.org/linux-usb/TYUPR06MB6217B105B059A7730C4F6EC8D2B9A@TYUPR06MB6217.apcprd06.prod.outlook.com/ Tested-by: 胡连勤 Fixes: de66754e9f80 ("xhci: sideband: add initial api to register a secondary interrupter entity") Cc: stable@vger.kernel.org Signed-off-by: Mathias Nyman Link: https://patch.msgid.link/20260115233758.364097-2-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/host/xhci-sideband.c b/drivers/usb/host/xhci-sideband.c index a85f62a73313..2bd77255032b 100644 --- a/drivers/usb/host/xhci-sideband.c +++ b/drivers/usb/host/xhci-sideband.c @@ -210,7 +210,6 @@ xhci_sideband_remove_endpoint(struct xhci_sideband *sb, return -ENODEV; __xhci_sideband_remove_endpoint(sb, ep); - xhci_initialize_ring_info(ep->ring); return 0; } diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index a148a1280126..4161c8c7721d 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -2891,16 +2891,25 @@ int xhci_stop_endpoint_sync(struct xhci_hcd *xhci, struct xhci_virt_ep *ep, int gfp_t gfp_flags) { struct xhci_command *command; + struct xhci_ep_ctx *ep_ctx; unsigned long flags; - int ret; + int ret = -ENODEV; command = xhci_alloc_command(xhci, true, gfp_flags); if (!command) return -ENOMEM; spin_lock_irqsave(&xhci->lock, flags); - ret = xhci_queue_stop_endpoint(xhci, command, ep->vdev->slot_id, - ep->ep_index, suspend); + + /* make sure endpoint exists and is running before stopping it */ + if (ep->ring) { + ep_ctx = xhci_get_ep_ctx(xhci, ep->vdev->out_ctx, ep->ep_index); + if (GET_EP_CTX_STATE(ep_ctx) == EP_STATE_RUNNING) + ret = xhci_queue_stop_endpoint(xhci, command, + ep->vdev->slot_id, + ep->ep_index, suspend); + } + if (ret < 0) { spin_unlock_irqrestore(&xhci->lock, flags); goto out;