On Thu, Dec 22, 2022 at 07:29:12AM +0000, Jimmy Hu wrote: > When the host controller is not responding, all URBs queued to all > endpoints need to be killed. This can cause a kernel panic if we > dereference an invalid endpoint. > > Fix this by using xhci_get_virt_ep() helper to find the endpoint and > checking if the endpoint is valid before dereferencing it. > > [233311.853271] xhci-hcd xhci-hcd.1.auto: xHCI host controller not responding, assume dead > [233311.853393] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000e8 > > [233311.853964] pc : xhci_hc_died+0x10c/0x270 > [233311.853971] lr : xhci_hc_died+0x1ac/0x270 > > [233311.854077] Call trace: > [233311.854085] xhci_hc_died+0x10c/0x270 > [233311.854093] xhci_stop_endpoint_command_watchdog+0x100/0x1a4 > [233311.854105] call_timer_fn+0x50/0x2d4 > [233311.854112] expire_timers+0xac/0x2e4 > [233311.854118] run_timer_softirq+0x300/0xabc > [233311.854127] __do_softirq+0x148/0x528 > [233311.854135] irq_exit+0x194/0x1a8 > [233311.854143] __handle_domain_irq+0x164/0x1d0 > [233311.854149] gic_handle_irq.22273+0x10c/0x188 > [233311.854156] el1_irq+0xfc/0x1a8 > [233311.854175] lpm_cpuidle_enter+0x25c/0x418 [msm_pm] > [233311.854185] cpuidle_enter_state+0x1f0/0x764 > [233311.854194] do_idle+0x594/0x6ac > [233311.854201] cpu_startup_entry+0x7c/0x80 > [233311.854209] secondary_start_kernel+0x170/0x198 > > Fixes: 50e8725e7c42 ("xhci: Refactor command watchdog and fix split string.") > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Jimmy Hu <hhhuuu@xxxxxxxxxx> > --- > drivers/usb/host/xhci-ring.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c > index ddc30037f9ce..f5b0e1ce22af 100644 > --- a/drivers/usb/host/xhci-ring.c > +++ b/drivers/usb/host/xhci-ring.c > @@ -1169,7 +1169,10 @@ static void xhci_kill_endpoint_urbs(struct xhci_hcd *xhci, > struct xhci_virt_ep *ep; > struct xhci_ring *ring; > > - ep = &xhci->devs[slot_id]->eps[ep_index]; > + ep = xhci_get_virt_ep(xhci, slot_id, ep_index); > + if (!ep) > + return; > + xhci_get_virt_ep also adds check for slot_id == 0. It changes behaviour, do we really want to skip that slot? Original code went from 0 to MAX_HC_SLOTS-1. It seems to be off by one to me. Am I missing anything? Also, what about passing ep directly to xhci_kill_endpoint_urbs and do the check in xhci_hc_died? Not even compile tested: diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index ddc30037f9ce..5dac483c562a 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -1162,14 +1162,12 @@ static void xhci_kill_ring_urbs(struct xhci_hcd *xhci, struct xhci_ring *ring) } static void xhci_kill_endpoint_urbs(struct xhci_hcd *xhci, - int slot_id, int ep_index) + struct xhci_virt_ep *ep) { struct xhci_td *cur_td; struct xhci_td *tmp; - struct xhci_virt_ep *ep; struct xhci_ring *ring; - ep = &xhci->devs[slot_id]->eps[ep_index]; if ((ep->ep_state & EP_HAS_STREAMS) || (ep->ep_state & EP_GETTING_NO_STREAMS)) { int stream_id; @@ -1180,18 +1178,12 @@ static void xhci_kill_endpoint_urbs(struct xhci_hcd *xhci, if (!ring) continue; - xhci_dbg_trace(xhci, trace_xhci_dbg_cancel_urb, - "Killing URBs for slot ID %u, ep index %u, stream %u", - slot_id, ep_index, stream_id); xhci_kill_ring_urbs(xhci, ring); } } else { ring = ep->ring; if (!ring) return; - xhci_dbg_trace(xhci, trace_xhci_dbg_cancel_urb, - "Killing URBs for slot ID %u, ep index %u", - slot_id, ep_index); xhci_kill_ring_urbs(xhci, ring); } @@ -1217,6 +1209,7 @@ static void xhci_kill_endpoint_urbs(struct xhci_hcd *xhci, void xhci_hc_died(struct xhci_hcd *xhci) { int i, j; + struct xhci_virt_ep *ep; if (xhci->xhc_state & XHCI_STATE_DYING) return; @@ -1227,11 +1220,14 @@ void xhci_hc_died(struct xhci_hcd *xhci) xhci_cleanup_command_queue(xhci); /* return any pending urbs, remove may be waiting for them */ - for (i = 0; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) { + for (i = 0; i < HCS_MAX_SLOTS(xhci->hcs_params1); i++) { if (!xhci->devs[i]) continue; - for (j = 0; j < 31; j++) - xhci_kill_endpoint_urbs(xhci, i, j); + for (j = 0; j < EP_CTX_PER_DEV; j++) { + ep = &xhci->devs[i]->eps[j]; + if (ep) + xhci_kill_endpoint_urbs(xhci, ep); + } } /* inform usb core hc died if PCI remove isn't already handling it */ > if ((ep->ep_state & EP_HAS_STREAMS) || > (ep->ep_state & EP_GETTING_NO_STREAMS)) { > int stream_id; > -- > 2.39.0.314.g84b9a713c41-goog