This is a note to let you know that I've just added the patch titled
xhci: avoid race between disable slot command and host runtime suspend
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xhci-avoid-race-between-disable-slot-command-and-host-runtime-suspend.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7faac1953ed1f658f719cdf7bb7303fa5eef822c Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Date: Fri, 10 Dec 2021 16:17:35 +0200
Subject: xhci: avoid race between disable slot command and host runtime suspend
From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
commit 7faac1953ed1f658f719cdf7bb7303fa5eef822c upstream.
Make xhci_disable_slot() synchronous, thus ensuring it, and
xhci_free_dev() calling it return after xHC controller completes
the disable slot command.
Otherwise the roothub and xHC host may runtime suspend, and clear the
command ring while the disable slot command is being processed.
This causes a command completion mismatch as the completion event can't
be mapped to the correct command.
Command ring gets out of sync and commands time out.
Driver finally assumes host is unresponsive and bails out.
usb 2-4: USB disconnect, device number 10
xhci_hcd 0000:00:0d.0: ERROR mismatched command completion event
...
xhci_hcd 0000:00:0d.0: xHCI host controller not responding, assume dead
xhci_hcd 0000:00:0d.0: HC died; cleaning up
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20211210141735.1384209-3-mathias.nyman@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/host/xhci-hub.c | 1 +
drivers/usb/host/xhci-ring.c | 1 -
drivers/usb/host/xhci.c | 22 +++++++++++++++-------
3 files changed, 16 insertions(+), 8 deletions(-)
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -717,6 +717,7 @@ static int xhci_enter_test_mode(struct x
continue;
retval = xhci_disable_slot(xhci, i);
+ xhci_free_virt_device(xhci, i);
if (retval)
xhci_err(xhci, "Failed to disable slot %d, %d. Enter test mode anyway\n",
i, retval);
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1525,7 +1525,6 @@ static void xhci_handle_cmd_disable_slot
if (xhci->quirks & XHCI_EP_LIMIT_QUIRK)
/* Delete default control endpoint resources */
xhci_free_device_endpoint_resources(xhci, virt_dev, true);
- xhci_free_virt_device(xhci, slot_id);
}
static void xhci_handle_cmd_config_ep(struct xhci_hcd *xhci, int slot_id,
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3959,9 +3959,8 @@ static void xhci_free_dev(struct usb_hcd
del_timer_sync(&virt_dev->eps[i].stop_cmd_timer);
}
virt_dev->udev = NULL;
- ret = xhci_disable_slot(xhci, udev->slot_id);
- if (ret)
- xhci_free_virt_device(xhci, udev->slot_id);
+ xhci_disable_slot(xhci, udev->slot_id);
+ xhci_free_virt_device(xhci, udev->slot_id);
}
int xhci_disable_slot(struct xhci_hcd *xhci, u32 slot_id)
@@ -3971,7 +3970,7 @@ int xhci_disable_slot(struct xhci_hcd *x
u32 state;
int ret = 0;
- command = xhci_alloc_command(xhci, false, GFP_KERNEL);
+ command = xhci_alloc_command(xhci, true, GFP_KERNEL);
if (!command)
return -ENOMEM;
@@ -3996,6 +3995,15 @@ int xhci_disable_slot(struct xhci_hcd *x
}
xhci_ring_cmd_db(xhci);
spin_unlock_irqrestore(&xhci->lock, flags);
+
+ wait_for_completion(command->completion);
+
+ if (command->status != COMP_SUCCESS)
+ xhci_warn(xhci, "Unsuccessful disable slot %u command, status %d\n",
+ slot_id, command->status);
+
+ xhci_free_command(xhci, command);
+
return ret;
}
@@ -4104,9 +4112,8 @@ int xhci_alloc_dev(struct usb_hcd *hcd,
return 1;
disable_slot:
- ret = xhci_disable_slot(xhci, udev->slot_id);
- if (ret)
- xhci_free_virt_device(xhci, udev->slot_id);
+ xhci_disable_slot(xhci, udev->slot_id);
+ xhci_free_virt_device(xhci, udev->slot_id);
return 0;
}
@@ -4236,6 +4243,7 @@ static int xhci_setup_device(struct usb_
mutex_unlock(&xhci->mutex);
ret = xhci_disable_slot(xhci, udev->slot_id);
+ xhci_free_virt_device(xhci, udev->slot_id);
if (!ret)
xhci_alloc_dev(hcd, udev);
kfree(command->completion);
Patches currently in stable-queue which might be from mathias.nyman@xxxxxxxxxxxxxxx are
queue-5.15/xhci-avoid-race-between-disable-slot-command-and-host-runtime-suspend.patch
queue-5.15/xhci-remove-config_usb_default_persist-to-prevent-xhci-from-runtime-suspending.patch
