4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Mathias Nyman <[email protected]> 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 <[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: Sudip Mukherjee <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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(-) --- a/drivers/usb/host/xhci-mtk.c +++ b/drivers/usb/host/xhci-mtk.c @@ -724,14 +724,16 @@ static int xhci_mtk_remove(struct platfo 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); --- 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_d 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 */ --- a/drivers/usb/host/xhci-plat.c +++ b/drivers/usb/host/xhci-plat.c @@ -332,14 +332,16 @@ static int xhci_plat_remove(struct platf 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); --- a/drivers/usb/host/xhci-tegra.c +++ b/drivers/usb/host/xhci-tegra.c @@ -1178,6 +1178,7 @@ static int tegra_xusb_remove(struct plat 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); --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -669,8 +669,6 @@ static void xhci_stop(struct usb_hcd *hc /* 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; }
