This is a note to let you know that I've just added the patch titled
usb: host: xhci-plat: fix possible kernel oops while resuming
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-host-xhci-plat-fix-possible-kernel-oops-while-re.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c3913021c3bf1840e01e4f8819814265e5f36289
Author: Sergey Shtylyov <s.shtylyov@xxxxxx>
Date: Thu Oct 19 13:29:23 2023 +0300
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 <s.shtylyov@xxxxxx>
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20231019102924.2797346-19-mathias.nyman@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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)
