6.6-stable review patch. If anyone has any objections, please let me know.
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From: Sergey Shtylyov s.shtylyov@omp.ru
[ 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 s.shtylyov@omp.ru Signed-off-by: Mathias Nyman mathias.nyman@linux.intel.com Link: https://lore.kernel.org/r/20231019102924.2797346-19-mathias.nyman@linux.inte... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/host/xhci-plat.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c index 28218c8f18376..b93161374293b 100644 --- a/drivers/usb/host/xhci-plat.c +++ b/drivers/usb/host/xhci-plat.c @@ -458,23 +458,38 @@ 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, PMSG_RESUME); 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)