From 209f4a67d8b7d202346d4e45fad3e88a1fa1e3e2 Mon Sep 17 00:00:00 2001 From: Sergey Shtylyov Date: Thu, 19 Oct 2023 13:29:23 +0300 Subject: usb: host: xhci-plat: fix possible kernel oops while resuming [ Upstream commit a5f928db59519a15e82ecba4ae3e7cbf5a44715a ] If this driver enables the xHC clocks while resuming from sleep, it calls clk_prepare_enable() without checking for errors and blithely goes on to read/write the xHC's registers -- which, with the xHC not being clocked, at least on ARM32 usually causes an imprecise external abort exceptions which cause kernel oops. Currently, the chips for which the driver does the clock dance on suspend/resume seem to be the Broadcom STB SoCs, based on ARM32 CPUs, as it seems... Found by Linux Verification Center (linuxtesting.org) with the Svace static analysis tool. Fixes: 8bd954c56197 ("usb: host: xhci-plat: suspend and resume clocks") Signed-off-by: Sergey Shtylyov Signed-off-by: Mathias Nyman Link: https://lore.kernel.org/r/20231019102924.2797346-19-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/host/xhci-plat.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) (limited to 'drivers/usb') diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c index 5fb55bf19493..c9a101f0e8d0 100644 --- a/drivers/usb/host/xhci-plat.c +++ b/drivers/usb/host/xhci-plat.c @@ -456,23 +456,38 @@ static int __maybe_unused xhci_plat_resume(struct device *dev) int ret; if (!device_may_wakeup(dev) && (xhci->quirks & XHCI_SUSPEND_RESUME_CLKS)) { - clk_prepare_enable(xhci->clk); - clk_prepare_enable(xhci->reg_clk); + ret = clk_prepare_enable(xhci->clk); + if (ret) + return ret; + + ret = clk_prepare_enable(xhci->reg_clk); + if (ret) { + clk_disable_unprepare(xhci->clk); + return ret; + } } ret = xhci_priv_resume_quirk(hcd); if (ret) - return ret; + goto disable_clks; ret = xhci_resume(xhci, 0); if (ret) - return ret; + goto disable_clks; pm_runtime_disable(dev); pm_runtime_set_active(dev); pm_runtime_enable(dev); return 0; + +disable_clks: + if (!device_may_wakeup(dev) && (xhci->quirks & XHCI_SUSPEND_RESUME_CLKS)) { + clk_disable_unprepare(xhci->clk); + clk_disable_unprepare(xhci->reg_clk); + } + + return ret; } static int __maybe_unused xhci_plat_runtime_suspend(struct device *dev) -- cgit v1.2.3