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
