[PATCH] xhci: Keep interrupt disabled in initialization until host is running.

[PATCH] xhci: Keep interrupt disabled in initialization until host is running.

[Prashanth K]

From: Hongyu Xie <xy521521@gmail.com>

[ Upstream commit 808925075fb750804a60ff0710614466c396db4 ]

irq is disabled in xhci_quiesce(called by xhci_halt, with bit:2 cleared
in USBCMD register), but xhci_run(called by usb_add_hcd) re-enable it.
It's possible that you will receive thousands of interrupt requests
after initialization for 2.0 roothub. And you will get a lot of
warning like, "xHCI dying, ignoring interrupt. Shouldn't IRQs be
disabled?". This amount of interrupt requests will cause the entire
system to freeze.
This problem was first found on a device with ASM2142 host controller
on it.

[tidy up old code while moving it, reword header -Mathias]

Cc: stable@kernel.org
Signed-off-by: Hongyu Xie <xiehongyu1@kylinos.cn>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20220623111945.1557702-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/host/xhci.c | 34 +++++++++++++++++++++-------------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 541fe4d..7ee747e 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -607,8 +607,27 @@ static int xhci_init(struct usb_hcd *hcd)
 
 static int xhci_run_finished(struct xhci_hcd *xhci)
 {
+	unsigned long	flags;
+	u32		temp;
+
+	/*
+	 * Enable interrupts before starting the host (xhci 4.2 and 5.5.2).
+	 * Protect the short window before host is running with a lock
+	 */
+	spin_lock_irqsave(&xhci->lock, flags);
+
+	xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Enable interrupts");
+	temp = readl(&xhci->op_regs->command);
+	temp |= (CMD_EIE);
+	writel(temp, &xhci->op_regs->command);
+
+	xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Enable primary interrupter");
+	temp = readl(&xhci->ir_set->irq_pending);
+	writel(ER_IRQ_ENABLE(temp), &xhci->ir_set->irq_pending);
+
 	if (xhci_start(xhci)) {
 		xhci_halt(xhci);
+		spin_unlock_irqrestore(&xhci->lock, flags);
 		return -ENODEV;
 	}
 	xhci->shared_hcd->state = HC_STATE_RUNNING;
@@ -619,6 +638,8 @@ static int xhci_run_finished(struct xhci_hcd *xhci)
 
 	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
 			"Finished xhci_run for USB3 roothub");
+
+	spin_unlock_irqrestore(&xhci->lock, flags);
 	return 0;
 }
 
@@ -667,19 +688,6 @@ int xhci_run(struct usb_hcd *hcd)
 	temp |= (xhci->imod_interval / 250) & ER_IRQ_INTERVAL_MASK;
 	writel(temp, &xhci->ir_set->irq_control);
 
-	/* Set the HCD state before we enable the irqs */
-	temp = readl(&xhci->op_regs->command);
-	temp |= (CMD_EIE);
-	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
-			"// Enable interrupts, cmd = 0x%x.", temp);
-	writel(temp, &xhci->op_regs->command);
-
-	temp = readl(&xhci->ir_set->irq_pending);
-	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
-			"// Enabling event ring interrupter %p by writing 0x%x to irq_pending",
-			xhci->ir_set, (unsigned int) ER_IRQ_ENABLE(temp));
-	writel(ER_IRQ_ENABLE(temp), &xhci->ir_set->irq_pending);
-
 	if (xhci->quirks & XHCI_NEC_HOST) {
 		struct xhci_command *command;
 
-- 
2.7.4

Re: [PATCH] xhci: Keep interrupt disabled in initialization until host is running.

[Greg Kroah-Hartman]

On Fri, Sep 22, 2023 at 02:51:41PM +0530, Prashanth K wrote:
> From: Hongyu Xie <xy521521@gmail.com>
> 
> [ Upstream commit 808925075fb750804a60ff0710614466c396db4 ]
> 
> irq is disabled in xhci_quiesce(called by xhci_halt, with bit:2 cleared
> in USBCMD register), but xhci_run(called by usb_add_hcd) re-enable it.
> It's possible that you will receive thousands of interrupt requests
> after initialization for 2.0 roothub. And you will get a lot of
> warning like, "xHCI dying, ignoring interrupt. Shouldn't IRQs be
> disabled?". This amount of interrupt requests will cause the entire
> system to freeze.
> This problem was first found on a device with ASM2142 host controller
> on it.
> 
> [tidy up old code while moving it, reword header -Mathias]
> 
> Cc: stable@kernel.org
> Signed-off-by: Hongyu Xie <xiehongyu1@kylinos.cn>
> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
> Link: https://lore.kernel.org/r/20220623111945.1557702-2-mathias.nyman@linux.intel.com
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  drivers/usb/host/xhci.c | 34 +++++++++++++++++++++-------------
>  1 file changed, 21 insertions(+), 13 deletions(-)

What stable kernel(s) are you asking this to be applied to?

greg k-h

Re: [PATCH] xhci: Keep interrupt disabled in initialization until host is running.

[Prashanth K]

On 22-09-23 04:00 pm, Greg Kroah-Hartman wrote:
> On Fri, Sep 22, 2023 at 02:51:41PM +0530, Prashanth K wrote:
>> From: Hongyu Xie <xy521521@gmail.com>
>>
>> [ Upstream commit 808925075fb750804a60ff0710614466c396db4 ]
>>
>> irq is disabled in xhci_quiesce(called by xhci_halt, with bit:2 cleared
>> in USBCMD register), but xhci_run(called by usb_add_hcd) re-enable it.
>> It's possible that you will receive thousands of interrupt requests
>> after initialization for 2.0 roothub. And you will get a lot of
>> warning like, "xHCI dying, ignoring interrupt. Shouldn't IRQs be
>> disabled?". This amount of interrupt requests will cause the entire
>> system to freeze.
>> This problem was first found on a device with ASM2142 host controller
>> on it.
>>
>> [tidy up old code while moving it, reword header -Mathias]
>>
>> Cc: stable@kernel.org
>> Signed-off-by: Hongyu Xie <xiehongyu1@kylinos.cn>
>> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
>> Link: https://lore.kernel.org/r/20220623111945.1557702-2-mathias.nyman@linux.intel.com
>> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> ---
>>   drivers/usb/host/xhci.c | 34 +++++++++++++++++++++-------------
>>   1 file changed, 21 insertions(+), 13 deletions(-)
> 
> What stable kernel(s) are you asking this to be applied to?
> 
> greg k-h
Need this patch on v5.15, I had cc'ed "stable@kernel.org # 5.15", but 
looks like it didn't work. Should I resend this with SOB and CC tags?

Thanks,
Prashanth K

Re: [PATCH] xhci: Keep interrupt disabled in initialization until host is running.

[Greg Kroah-Hartman]

On Fri, Sep 22, 2023 at 04:03:26PM +0530, Prashanth K wrote:
> 
> 
> On 22-09-23 04:00 pm, Greg Kroah-Hartman wrote:
> > On Fri, Sep 22, 2023 at 02:51:41PM +0530, Prashanth K wrote:
> > > From: Hongyu Xie <xy521521@gmail.com>
> > > 
> > > [ Upstream commit 808925075fb750804a60ff0710614466c396db4 ]
> > > 
> > > irq is disabled in xhci_quiesce(called by xhci_halt, with bit:2 cleared
> > > in USBCMD register), but xhci_run(called by usb_add_hcd) re-enable it.
> > > It's possible that you will receive thousands of interrupt requests
> > > after initialization for 2.0 roothub. And you will get a lot of
> > > warning like, "xHCI dying, ignoring interrupt. Shouldn't IRQs be
> > > disabled?". This amount of interrupt requests will cause the entire
> > > system to freeze.
> > > This problem was first found on a device with ASM2142 host controller
> > > on it.
> > > 
> > > [tidy up old code while moving it, reword header -Mathias]
> > > 
> > > Cc: stable@kernel.org
> > > Signed-off-by: Hongyu Xie <xiehongyu1@kylinos.cn>
> > > Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
> > > Link: https://lore.kernel.org/r/20220623111945.1557702-2-mathias.nyman@linux.intel.com
> > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > ---
> > >   drivers/usb/host/xhci.c | 34 +++++++++++++++++++++-------------
> > >   1 file changed, 21 insertions(+), 13 deletions(-)
> > 
> > What stable kernel(s) are you asking this to be applied to?
> > 
> > greg k-h
> Need this patch on v5.15, I had cc'ed "stable@kernel.org # 5.15", but looks
> like it didn't work. Should I resend this with SOB and CC tags?

Yes please.

thanks,

greg k-h