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patch "xhci: Fix leaking USB3 shared_hcd at xhci removal" added to usb-linus

PATCH [email protected] 1 participant 1 message Nov 10, 2018

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This is a note to let you know that I've just added the patch titled

xhci: Fix leaking USB3 shared_hcd at xhci removal

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

Quoted 1 line

From f068090426ea8d72c408ebd42953a82a88e2282c Mon Sep 17 00:00:00 2001

From: Mathias Nyman <[email protected]>
Date: Fri, 9 Nov 2018 17:21:17 +0200
Subject: xhci: Fix leaking USB3 shared_hcd at xhci removal

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 <[email protected]>
Cc Chunfeng Yun <[email protected]>
Cc Thierry Reding <[email protected]>
Cc Jianguo Sun <[email protected]>
Cc <[email protected]>
Reported-by Jack Pham <[email protected]>
Tested-by Jack Pham <[email protected]>
Tested-by Peter Chen <[email protected]>
Signed-off-by Mathias Nyman <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 drivers/usb/host/xhci-histb.c | 6 ++++--
 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 --
 6 files changed, 14 insertions(+), 8 deletions(-)
drivers/usb/host/xhci-histb.c +4 -2
index 27f00160332e..3c4abb5a1c3f 100644
@@ -325,14 +325,16 @@ static int xhci_histb_remove(struct platform_device *dev)
 	struct xhci_hcd_histb *histb = platform_get_drvdata(dev);
 	struct usb_hcd *hcd = histb->hcd;
 	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
+	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;
 	device_wakeup_disable(&dev->dev);
 
 	usb_remove_hcd(hcd);
-	usb_put_hcd(xhci->shared_hcd);
+	usb_put_hcd(shared_hcd);
 
 	xhci_histb_host_disable(histb);
 	usb_put_hcd(hcd);
drivers/usb/host/xhci-mtk.c +4 -2
index 71d0d33c3286..60987c787e44 100644
@@ -590,12 +590,14 @@ 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;
 	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);
drivers/usb/host/xhci-pci.c +1 -0
index 01c57055c0c5..1fb448cd2667 100644
@@ -380,6 +380,7 @@ 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 */
drivers/usb/host/xhci-plat.c +4 -2
index 32b5574ad5c5..ef09cb06212f 100644
@@ -362,14 +362,16 @@ static int xhci_plat_remove(struct platform_device *dev)
 	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
 	struct clk *clk = xhci->clk;
 	struct clk *reg_clk = xhci->reg_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);
 
 	clk_disable_unprepare(clk);
 	clk_disable_unprepare(reg_clk);
drivers/usb/host/xhci-tegra.c +1 -0
index 6b5db344de30..938ff06c0349 100644
@@ -1303,6 +1303,7 @@ 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);
drivers/usb/host/xhci.c +0 -2
index 0420eefa647a..c928dbbff881 100644
@@ -719,8 +719,6 @@ 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;
 	}
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2.19.1