Re: FAILED: patch "[PATCH] xhci: Fix leaking USB3 shared_hcd at xhci removal" failed to apply to 4.14-stable tree

[Sudip Mukherjee <sudipm.mukherjee@gmail.com>]

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Hi Greg,

On Wed, Nov 28, 2018 at 10:26:44AM +0100, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 4.14-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.

The attached backported patch should apply to 4.14-stable tree.
The original patch was also changing drivers/usb/host/xhci-histb.c which
is not needed in v4.14.y as that file was created in v4.18 by:
c508f41da078 ("xhci: hisilicon: support HiSilicon STB xHCI host controller")

--
Regards
Sudip

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From 103fd0c5188d19284967e1019588700e2b2a6a67 Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman@linux.intel.com>
Date: Fri, 9 Nov 2018 17:21:17 +0200
Subject: [PATCH] xhci: Fix leaking USB3 shared_hcd at xhci removal

commit f068090426ea8d72c408ebd42953a82a88e2282c upstream

Ensure that the shared_hcd pointer is valid when calling usb_put_hcd()

The shared_hcd is removed and freed in xhci by first calling
usb_remove_hcd(xhci->shared_hcd), and later
usb_put_hcd(xhci->shared_hcd)

Afer commit fe190ed0d602 ("xhci: Do not halt the host until both HCD have
disconnected their devices.") the shared_hcd was never properly put as
xhci->shared_hcd was set to NULL before usb_put_hcd(xhci->shared_hcd) was
called.

shared_hcd (USB3) is removed before primary hcd (USB2).
While removing the primary hcd we might need to handle xhci interrupts
to cleanly remove last USB2 devices, therefore we need to set
xhci->shared_hcd to NULL before removing the primary hcd to let xhci
interrupt handler know shared_hcd is no longer available.

xhci-plat.c, xhci-histb.c and xhci-mtk first create both their hcd's before
adding them. so to keep the correct reverse removal order use a temporary
shared_hcd variable for them.
For more details see commit 4ac53087d6d4 ("usb: xhci: plat: Create both
HCDs before adding them")

Fixes: fe190ed0d602 ("xhci: Do not halt the host until both HCD have disconnected their devices.")
Cc: Joel Stanley <joel@jms.id.au>
Cc: Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Jianguo Sun <sunjianguo1@huawei.com>
Cc: <stable@vger.kernel.org>
Reported-by: Jack Pham <jackp@codeaurora.org>
Tested-by: Jack Pham <jackp@codeaurora.org>
Tested-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
---
 drivers/usb/host/xhci-mtk.c   | 6 ++++--
 drivers/usb/host/xhci-pci.c   | 1 +
 drivers/usb/host/xhci-plat.c  | 6 ++++--
 drivers/usb/host/xhci-tegra.c | 1 +
 drivers/usb/host/xhci.c       | 2 --
 5 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
index 510d28a9d190..35aecbcac6f7 100644
--- a/drivers/usb/host/xhci-mtk.c
+++ b/drivers/usb/host/xhci-mtk.c
@@ -724,14 +724,16 @@ static int xhci_mtk_remove(struct platform_device *dev)
 	struct xhci_hcd_mtk *mtk = platform_get_drvdata(dev);
 	struct usb_hcd	*hcd = mtk->hcd;
 	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
+	struct usb_hcd  *shared_hcd = xhci->shared_hcd;
 
-	usb_remove_hcd(xhci->shared_hcd);
+	usb_remove_hcd(shared_hcd);
+	xhci->shared_hcd = NULL;
 	xhci_mtk_phy_power_off(mtk);
 	xhci_mtk_phy_exit(mtk);
 	device_init_wakeup(&dev->dev, false);
 
 	usb_remove_hcd(hcd);
-	usb_put_hcd(xhci->shared_hcd);
+	usb_put_hcd(shared_hcd);
 	usb_put_hcd(hcd);
 	xhci_mtk_sch_exit(mtk);
 	xhci_mtk_clks_disable(mtk);
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 0fbc549cc55c..1de006aebec5 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -370,6 +370,7 @@ static void xhci_pci_remove(struct pci_dev *dev)
 	if (xhci->shared_hcd) {
 		usb_remove_hcd(xhci->shared_hcd);
 		usb_put_hcd(xhci->shared_hcd);
+		xhci->shared_hcd = NULL;
 	}
 
 	/* Workaround for spurious wakeups at shutdown with HSW */
diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index 830dd0dbbce0..108a212294bf 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -332,14 +332,16 @@ static int xhci_plat_remove(struct platform_device *dev)
 	struct usb_hcd	*hcd = platform_get_drvdata(dev);
 	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
 	struct clk *clk = xhci->clk;
+	struct usb_hcd *shared_hcd = xhci->shared_hcd;
 
 	xhci->xhc_state |= XHCI_STATE_REMOVING;
 
-	usb_remove_hcd(xhci->shared_hcd);
+	usb_remove_hcd(shared_hcd);
+	xhci->shared_hcd = NULL;
 	usb_phy_shutdown(hcd->usb_phy);
 
 	usb_remove_hcd(hcd);
-	usb_put_hcd(xhci->shared_hcd);
+	usb_put_hcd(shared_hcd);
 
 	if (!IS_ERR(clk))
 		clk_disable_unprepare(clk);
diff --git a/drivers/usb/host/xhci-tegra.c b/drivers/usb/host/xhci-tegra.c
index 32ddafe7af87..28df32d85671 100644
--- a/drivers/usb/host/xhci-tegra.c
+++ b/drivers/usb/host/xhci-tegra.c
@@ -1178,6 +1178,7 @@ static int tegra_xusb_remove(struct platform_device *pdev)
 
 	usb_remove_hcd(xhci->shared_hcd);
 	usb_put_hcd(xhci->shared_hcd);
+	xhci->shared_hcd = NULL;
 	usb_remove_hcd(tegra->hcd);
 	usb_put_hcd(tegra->hcd);
 
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 930eecd86429..c78de07c4d00 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -669,8 +669,6 @@ static void xhci_stop(struct usb_hcd *hcd)
 
 	/* Only halt host and free memory after both hcds are removed */
 	if (!usb_hcd_is_primary_hcd(hcd)) {
-		/* usb core will free this hcd shortly, unset pointer */
-		xhci->shared_hcd = NULL;
 		mutex_unlock(&xhci->mutex);
 		return;
 	}
-- 
2.11.0