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From: Mathias Nyman <mathias.nyman@linux.intel.com>
To: <gregkh@linuxfoundation.org>
Cc: <linux-usb@vger.kernel.org>, Sergey Shtylyov <s.shtylyov@omp.ru>,
	Mathias Nyman <mathias.nyman@linux.intel.com>
Subject: [PATCH 18/19] usb: host: xhci-plat: fix possible kernel oops while resuming
Date: Thu, 19 Oct 2023 13:29:23 +0300	[thread overview]
Message-ID: <20231019102924.2797346-19-mathias.nyman@linux.intel.com> (raw)
In-Reply-To: <20231019102924.2797346-1-mathias.nyman@linux.intel.com>

From: Sergey Shtylyov <s.shtylyov@omp.ru>

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>
---
 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 28218c8f1837..b93161374293 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)
-- 
2.25.1


  parent reply	other threads:[~2023-10-19 10:28 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-19 10:29 [PATCH 00/19] xhci features for usb-next Mathias Nyman
2023-10-19 10:29 ` [PATCH 01/19] xhci: pass port structure to tracing instead of port number Mathias Nyman
2023-10-19 10:29 ` [PATCH 02/19] xhci: Add busnumber to port tracing Mathias Nyman
2023-10-19 10:29 ` [PATCH 03/19] xhci: expand next_trb() helper to support more ring types Mathias Nyman
2023-10-19 10:29 ` [PATCH 04/19] xhci: Set DESI bits in ERDP register correctly Mathias Nyman
2023-10-19 10:29 ` [PATCH 05/19] xhci: Use more than one Event Ring segment Mathias Nyman
2023-10-19 10:29 ` [PATCH 06/19] xhci: Adjust segment numbers after ring expansion Mathias Nyman
2023-10-19 10:29 ` [PATCH 07/19] xhci: Update last segment pointer after Event Ring expansion Mathias Nyman
2023-10-19 10:29 ` [PATCH 08/19] xhci: Expose segment numbers in debugfs Mathias Nyman
2023-10-19 10:29 ` [PATCH 09/19] xhci: Clean up ERST_PTR_MASK inversion Mathias Nyman
2023-10-19 10:29 ` [PATCH 10/19] xhci: Clean up stale comment on ERST_SIZE macro Mathias Nyman
2023-10-19 10:29 ` [PATCH 11/19] xhci: Clean up xhci_{alloc,free}_erst() declarations Mathias Nyman
2023-10-19 10:29 ` [PATCH 12/19] xhci: simplify event ring dequeue tracking for transfer events Mathias Nyman
2023-10-19 10:29 ` [PATCH 13/19] xhci: Simplify event ring dequeue pointer update for port change events Mathias Nyman
2023-10-19 10:29 ` [PATCH 14/19] xhci: Loosen RPM as default policy to cover for AMD xHC 1.1 Mathias Nyman
2023-10-19 10:29 ` [PATCH 15/19] xhci: Enable RPM on controllers that support low-power states Mathias Nyman
2023-10-19 10:29 ` [PATCH 16/19] xhci: split free interrupter into separate remove and free parts Mathias Nyman
2023-10-19 10:29 ` [PATCH 17/19] usb: xhci: Implement xhci_handshake_check_state() helper Mathias Nyman
2023-10-19 10:29 ` Mathias Nyman [this message]
2023-10-19 10:29 ` [PATCH 19/19] usb: host: xhci: Avoid XHCI resume delay if SSUSB device is not present Mathias Nyman

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