RE: [PATCH v2 1/4] usb: renesas_usbhs: fix spinlock suspected in a gadget complete function
Hi,
Hi,
On Fri, Mar 13, 2015 at 01:14:01AM +, yoshihiro shimoda wrote:
diff --git a/drivers/usb/renesas_usbhs/mod_gadget.c
b/drivers/usb/renesas_usbhs/mod_gadget.c
index e0384af77e56..e9d75d85be59 100644
--- a/drivers/usb/renesas_usbhs/mod_gadget.c
+++ b/drivers/usb/renesas_usbhs/mod_gadget.c
@@ -119,7 +119,7 @@ struct usbhsg_recip_handle {
/*
* queue push/pop
*/
-static void usbhsg_queue_pop(struct usbhsg_uep *uep,
+static void __usbhsg_queue_pop(struct usbhsg_uep *uep,
struct usbhsg_request *ureq,
int status)
{
@@ -133,6 +133,15 @@ static void usbhsg_queue_pop(struct usbhsg_uep
*uep,
usb_gadget_giveback_request(uep-ep, ureq-req);
}
+static void usbhsg_queue_pop(struct usbhsg_uep *uep,
+ struct usbhsg_request *ureq,
+ int status)
+{
+ usbhs_lock(priv, flags);
+ __usbhsg_queue_pop(uep, ureq, status);
+ usbhs_unlock(priv, flags);
+}
+
static void usbhsg_queue_done(struct usbhs_priv *priv, struct
usbhs_pkt *pkt)
{
struct usbhs_pipe *pipe = pkt-pipe;
then, for cases where lock is already held you call
__usbhsg_queue_pop()
and for all other cases, call usbhsg_queue_pop().
Thank you for the suggestion. However, we cannot use this
usbhsg_queue_pop() because a gadget driver might call usb_ep_queue()
in the complete function and this driver calls usbhs_lock() in the
usb_ep_queue().
right, in that case just call __usbhs_queue_pop() directly.
Yes. So, my understanding is that this driver always calls
__usbhs_queue_pop()
because this driver cannot know that a gadget driver calls usb_ep_queue()
or not
in the complete function.
but you don't need to know that. All you have to do is spin_unlock()
before calling usb_gadget_giveback_request(), look at
drivers/usb/dwc3/gadget.c::dwc3_gadget_giveback()
Thank you for the suggestion. I understood it.
Perhaps my explanation was bad, but this issue was caused by the
following conditions:
- I use the renesas_usbhs driver as udc.
- I use an old usb-dmac driver that the callback runs on a kthread.
- I use the ncm driver. In this environment, the ncm driver might
cause a spinlock suspected.
As an old solution, I fixed the renesas_usbhs driver by this patch.
However, if I use a new usb-dmac driver that the callback runs on a
tasklet, I don't need this patch. (This is a new solution.)
then differentiate based on some revision register or something like
that ?
Sorry for the lack information. I am submitting this usb-dmac driver that
the callback runs on a tasklet now. This means that the driver is not
merged yet. So, I think that we don't need to differentiate.
But as soon as your driver gets merged, you will need to differentiate,
right ?
Right. So, I will submit v3 patch soon.
Best regards,
Yoshihiro Shimoda
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Re: [PATCH v2 1/4] usb: renesas_usbhs: fix spinlock suspected in a gadget complete function
Hi,
On Fri, Mar 13, 2015 at 01:14:01AM +, yoshihiro shimoda wrote:
diff --git a/drivers/usb/renesas_usbhs/mod_gadget.c
b/drivers/usb/renesas_usbhs/mod_gadget.c
index e0384af77e56..e9d75d85be59 100644
--- a/drivers/usb/renesas_usbhs/mod_gadget.c
+++ b/drivers/usb/renesas_usbhs/mod_gadget.c
@@ -119,7 +119,7 @@ struct usbhsg_recip_handle {
/*
* queue push/pop
*/
-static void usbhsg_queue_pop(struct usbhsg_uep *uep,
+static void __usbhsg_queue_pop(struct usbhsg_uep *uep,
struct usbhsg_request *ureq,
int status)
{
@@ -133,6 +133,15 @@ static void usbhsg_queue_pop(struct usbhsg_uep
*uep,
usb_gadget_giveback_request(uep-ep, ureq-req);
}
+static void usbhsg_queue_pop(struct usbhsg_uep *uep,
+struct usbhsg_request *ureq,
+int status)
+{
+ usbhs_lock(priv, flags);
+ __usbhsg_queue_pop(uep, ureq, status);
+ usbhs_unlock(priv, flags);
+}
+
static void usbhsg_queue_done(struct usbhs_priv *priv, struct
usbhs_pkt *pkt)
{
struct usbhs_pipe *pipe = pkt-pipe;
then, for cases where lock is already held you call __usbhsg_queue_pop()
and for all other cases, call usbhsg_queue_pop().
Thank you for the suggestion. However, we cannot use this
usbhsg_queue_pop() because a gadget driver might call usb_ep_queue()
in the complete function and this driver calls usbhs_lock() in the
usb_ep_queue().
right, in that case just call __usbhs_queue_pop() directly.
Yes. So, my understanding is that this driver always calls __usbhs_queue_pop()
because this driver cannot know that a gadget driver calls usb_ep_queue() or
not
in the complete function.
but you don't need to know that. All you have to do is spin_unlock()
before calling usb_gadget_giveback_request(), look at
drivers/usb/dwc3/gadget.c::dwc3_gadget_giveback()
Perhaps my explanation was bad, but this issue was caused by the
following conditions:
- I use the renesas_usbhs driver as udc.
- I use an old usb-dmac driver that the callback runs on a kthread.
- I use the ncm driver. In this environment, the ncm driver might
cause a spinlock suspected.
As an old solution, I fixed the renesas_usbhs driver by this patch.
However, if I use a new usb-dmac driver that the callback runs on a
tasklet, I don't need this patch. (This is a new solution.)
then differentiate based on some revision register or something like
that ?
Sorry for the lack information. I am submitting this usb-dmac driver that
the callback runs on a tasklet now. This means that the driver is not
merged yet. So, I think that we don't need to differentiate.
But as soon as your driver gets merged, you will need to differentiate,
right ?
--
balbi
signature.asc
Description: Digital signature
Re: [PATCH v2 1/4] usb: renesas_usbhs: fix spinlock suspected in a gadget complete function
Hi,
On Thu, Mar 12, 2015 at 05:40:56AM +, yoshihiro shimoda wrote:
Hi,
On Thu, Mar 12, 2015 at 04:33:41AM +, yoshihiro shimoda wrote:
Hi Geert-san again,
Hi Geert-san,
Thank you for the reply again!
Hi Shimoda-san,
On Mon, Feb 16, 2015 at 2:52 AM, Yoshihiro Shimoda
yoshihiro.shimoda...@renesas.com wrote:
According to the gadget.h, a complete function will always be
called
with interrupts disabled. However, sometimes usbhsg_queue_pop()
function
is called with interrupts enabled. So, this function should calls
local_irq_save() before this calls the
usb_gadget_giveback_request().
Otherwise, there is possible to cause a spinlock suspected in a
gadget
complete function.
I still feel uneasy about adding the call to local_irq_save(), as the
need for
this is usually an indicator of another locking problem.
I also think that I would like to avoid using local_irq_save().
But, I have no idea to resolve this issue for now.
After I modified usb-dmac driver to use a tasklet instead of a kthread,
this issue disappeared.
My understanding is the followings:
- According to the backtrace below, during usbhsf_dma_complete() was
running,
a softirq happened. After ncm_tx_tasklet() was called, the issue
happened.
http://thread.gmane.org/gmane.linux.usb.general/122023/focus=43729
- This means that usbhsf_dma_complete() ran on a kthread. So, ncm driver
is able
to do the ncm_tx_tasklet().
- After the current usb-dmac driver, since usbhsf_dma_complete() runs on
a tasklet,
ncm driver is not able to do the ncm_tx_tasklet during
usbhsf_dma_complete() was running.
So, I would like to recall this patch and I will resubmit this patch
series as v3.
try something like below:
diff --git a/drivers/usb/renesas_usbhs/mod_gadget.c
b/drivers/usb/renesas_usbhs/mod_gadget.c
index e0384af77e56..e9d75d85be59 100644
--- a/drivers/usb/renesas_usbhs/mod_gadget.c
+++ b/drivers/usb/renesas_usbhs/mod_gadget.c
@@ -119,7 +119,7 @@ struct usbhsg_recip_handle {
/*
* queue push/pop
*/
-static void usbhsg_queue_pop(struct usbhsg_uep *uep,
+static void __usbhsg_queue_pop(struct usbhsg_uep *uep,
struct usbhsg_request *ureq,
int status)
{
@@ -133,6 +133,15 @@ static void usbhsg_queue_pop(struct usbhsg_uep *uep,
usb_gadget_giveback_request(uep-ep, ureq-req);
}
+static void usbhsg_queue_pop(struct usbhsg_uep *uep,
+struct usbhsg_request *ureq,
+int status)
+{
+ usbhs_lock(priv, flags);
+ __usbhsg_queue_pop(uep, ureq, status);
+ usbhs_unlock(priv, flags);
+}
+
static void usbhsg_queue_done(struct usbhs_priv *priv, struct usbhs_pkt
*pkt)
{
struct usbhs_pipe *pipe = pkt-pipe;
then, for cases where lock is already held you call __usbhsg_queue_pop()
and for all other cases, call usbhsg_queue_pop().
Thank you for the suggestion. However, we cannot use this
usbhsg_queue_pop() because a gadget driver might call usb_ep_queue()
in the complete function and this driver calls usbhs_lock() in the
usb_ep_queue().
right, in that case just call __usbhs_queue_pop() directly.
Perhaps my explanation was bad, but this issue was caused by the
following conditions:
- I use the renesas_usbhs driver as udc.
- I use an old usb-dmac driver that the callback runs on a kthread.
- I use the ncm driver. In this environment, the ncm driver might
cause a spinlock suspected.
As an old solution, I fixed the renesas_usbhs driver by this patch.
However, if I use a new usb-dmac driver that the callback runs on a
tasklet, I don't need this patch. (This is a new solution.)
then differentiate based on some revision register or something like
that ?
--
balbi
signature.asc
Description: Digital signature
RE: [PATCH v2 1/4] usb: renesas_usbhs: fix spinlock suspected in a gadget complete function
Hi,
Hi,
On Thu, Mar 12, 2015 at 05:40:56AM +, yoshihiro shimoda wrote:
Hi,
snip
try something like below:
diff --git a/drivers/usb/renesas_usbhs/mod_gadget.c
b/drivers/usb/renesas_usbhs/mod_gadget.c
index e0384af77e56..e9d75d85be59 100644
--- a/drivers/usb/renesas_usbhs/mod_gadget.c
+++ b/drivers/usb/renesas_usbhs/mod_gadget.c
@@ -119,7 +119,7 @@ struct usbhsg_recip_handle {
/*
* queue push/pop
*/
-static void usbhsg_queue_pop(struct usbhsg_uep *uep,
+static void __usbhsg_queue_pop(struct usbhsg_uep *uep,
struct usbhsg_request *ureq,
int status)
{
@@ -133,6 +133,15 @@ static void usbhsg_queue_pop(struct usbhsg_uep *uep,
usb_gadget_giveback_request(uep-ep, ureq-req);
}
+static void usbhsg_queue_pop(struct usbhsg_uep *uep,
+ struct usbhsg_request *ureq,
+ int status)
+{
+ usbhs_lock(priv, flags);
+ __usbhsg_queue_pop(uep, ureq, status);
+ usbhs_unlock(priv, flags);
+}
+
static void usbhsg_queue_done(struct usbhs_priv *priv, struct usbhs_pkt
*pkt)
{
struct usbhs_pipe *pipe = pkt-pipe;
then, for cases where lock is already held you call __usbhsg_queue_pop()
and for all other cases, call usbhsg_queue_pop().
Thank you for the suggestion. However, we cannot use this
usbhsg_queue_pop() because a gadget driver might call usb_ep_queue()
in the complete function and this driver calls usbhs_lock() in the
usb_ep_queue().
right, in that case just call __usbhs_queue_pop() directly.
Yes. So, my understanding is that this driver always calls __usbhs_queue_pop()
because this driver cannot know that a gadget driver calls usb_ep_queue() or not
in the complete function.
Perhaps my explanation was bad, but this issue was caused by the
following conditions:
- I use the renesas_usbhs driver as udc.
- I use an old usb-dmac driver that the callback runs on a kthread.
- I use the ncm driver. In this environment, the ncm driver might
cause a spinlock suspected.
As an old solution, I fixed the renesas_usbhs driver by this patch.
However, if I use a new usb-dmac driver that the callback runs on a
tasklet, I don't need this patch. (This is a new solution.)
then differentiate based on some revision register or something like
that ?
Sorry for the lack information. I am submitting this usb-dmac driver that
the callback runs on a tasklet now. This means that the driver is not
merged yet. So, I think that we don't need to differentiate.
Best regards,
Yoshihiro Shimoda
--
balbi
--
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the body of a message to majord...@vger.kernel.org
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RE: [PATCH v2 1/4] usb: renesas_usbhs: fix spinlock suspected in a gadget complete function
Hi Geert-san again,
Hi Geert-san,
Thank you for the reply again!
Hi Shimoda-san,
On Mon, Feb 16, 2015 at 2:52 AM, Yoshihiro Shimoda
yoshihiro.shimoda...@renesas.com wrote:
According to the gadget.h, a complete function will always be called
with interrupts disabled. However, sometimes usbhsg_queue_pop() function
is called with interrupts enabled. So, this function should calls
local_irq_save() before this calls the usb_gadget_giveback_request().
Otherwise, there is possible to cause a spinlock suspected in a gadget
complete function.
I still feel uneasy about adding the call to local_irq_save(), as the need
for
this is usually an indicator of another locking problem.
I also think that I would like to avoid using local_irq_save().
But, I have no idea to resolve this issue for now.
After I modified usb-dmac driver to use a tasklet instead of a kthread,
this issue disappeared.
My understanding is the followings:
- According to the backtrace below, during usbhsf_dma_complete() was running,
a softirq happened. After ncm_tx_tasklet() was called, the issue happened.
http://thread.gmane.org/gmane.linux.usb.general/122023/focus=43729
- This means that usbhsf_dma_complete() ran on a kthread. So, ncm driver is able
to do the ncm_tx_tasklet().
- After the current usb-dmac driver, since usbhsf_dma_complete() runs on a
tasklet,
ncm driver is not able to do the ncm_tx_tasklet during usbhsf_dma_complete()
was running.
So, I would like to recall this patch and I will resubmit this patch series as
v3.
Best regards,
Yoshihiro Shimoda
N�r��yb�X��ǧv�^�){.n�+{��^n�r���z���h��� �G���h�(�階�ݢj���m��z�ޖ���f���h���~�m�
Re: [PATCH v2 1/4] usb: renesas_usbhs: fix spinlock suspected in a gadget complete function
Hi,
On Thu, Mar 12, 2015 at 04:33:41AM +, yoshihiro shimoda wrote:
Hi Geert-san again,
Hi Geert-san,
Thank you for the reply again!
Hi Shimoda-san,
On Mon, Feb 16, 2015 at 2:52 AM, Yoshihiro Shimoda
yoshihiro.shimoda...@renesas.com wrote:
According to the gadget.h, a complete function will always be called
with interrupts disabled. However, sometimes usbhsg_queue_pop() function
is called with interrupts enabled. So, this function should calls
local_irq_save() before this calls the usb_gadget_giveback_request().
Otherwise, there is possible to cause a spinlock suspected in a gadget
complete function.
I still feel uneasy about adding the call to local_irq_save(), as the
need for
this is usually an indicator of another locking problem.
I also think that I would like to avoid using local_irq_save().
But, I have no idea to resolve this issue for now.
After I modified usb-dmac driver to use a tasklet instead of a kthread,
this issue disappeared.
My understanding is the followings:
- According to the backtrace below, during usbhsf_dma_complete() was running,
a softirq happened. After ncm_tx_tasklet() was called, the issue happened.
http://thread.gmane.org/gmane.linux.usb.general/122023/focus=43729
- This means that usbhsf_dma_complete() ran on a kthread. So, ncm driver is
able
to do the ncm_tx_tasklet().
- After the current usb-dmac driver, since usbhsf_dma_complete() runs on a
tasklet,
ncm driver is not able to do the ncm_tx_tasklet during
usbhsf_dma_complete() was running.
So, I would like to recall this patch and I will resubmit this patch series
as v3.
try something like below:
diff --git a/drivers/usb/renesas_usbhs/mod_gadget.c
b/drivers/usb/renesas_usbhs/mod_gadget.c
index e0384af77e56..e9d75d85be59 100644
--- a/drivers/usb/renesas_usbhs/mod_gadget.c
+++ b/drivers/usb/renesas_usbhs/mod_gadget.c
@@ -119,7 +119,7 @@ struct usbhsg_recip_handle {
/*
* queue push/pop
*/
-static void usbhsg_queue_pop(struct usbhsg_uep *uep,
+static void __usbhsg_queue_pop(struct usbhsg_uep *uep,
struct usbhsg_request *ureq,
int status)
{
@@ -133,6 +133,15 @@ static void usbhsg_queue_pop(struct usbhsg_uep *uep,
usb_gadget_giveback_request(uep-ep, ureq-req);
}
+static void usbhsg_queue_pop(struct usbhsg_uep *uep,
+struct usbhsg_request *ureq,
+int status)
+{
+ usbhs_lock(priv, flags);
+ __usbhsg_queue_pop(uep, ureq, status);
+ usbhs_unlock(priv, flags);
+}
+
static void usbhsg_queue_done(struct usbhs_priv *priv, struct usbhs_pkt *pkt)
{
struct usbhs_pipe *pipe = pkt-pipe;
then, for cases where lock is already held you call __usbhsg_queue_pop()
and for all other cases, call usbhsg_queue_pop().
--
balbi
signature.asc
Description: Digital signature
RE: [PATCH v2 1/4] usb: renesas_usbhs: fix spinlock suspected in a gadget complete function
Hi,
On Thu, Mar 12, 2015 at 04:33:41AM +, yoshihiro shimoda wrote:
Hi Geert-san again,
Hi Geert-san,
Thank you for the reply again!
Hi Shimoda-san,
On Mon, Feb 16, 2015 at 2:52 AM, Yoshihiro Shimoda
yoshihiro.shimoda...@renesas.com wrote:
According to the gadget.h, a complete function will always be called
with interrupts disabled. However, sometimes usbhsg_queue_pop()
function
is called with interrupts enabled. So, this function should calls
local_irq_save() before this calls the usb_gadget_giveback_request().
Otherwise, there is possible to cause a spinlock suspected in a gadget
complete function.
I still feel uneasy about adding the call to local_irq_save(), as the
need for
this is usually an indicator of another locking problem.
I also think that I would like to avoid using local_irq_save().
But, I have no idea to resolve this issue for now.
After I modified usb-dmac driver to use a tasklet instead of a kthread,
this issue disappeared.
My understanding is the followings:
- According to the backtrace below, during usbhsf_dma_complete() was
running,
a softirq happened. After ncm_tx_tasklet() was called, the issue happened.
http://thread.gmane.org/gmane.linux.usb.general/122023/focus=43729
- This means that usbhsf_dma_complete() ran on a kthread. So, ncm driver is
able
to do the ncm_tx_tasklet().
- After the current usb-dmac driver, since usbhsf_dma_complete() runs on a
tasklet,
ncm driver is not able to do the ncm_tx_tasklet during
usbhsf_dma_complete() was running.
So, I would like to recall this patch and I will resubmit this patch series
as v3.
try something like below:
diff --git a/drivers/usb/renesas_usbhs/mod_gadget.c
b/drivers/usb/renesas_usbhs/mod_gadget.c
index e0384af77e56..e9d75d85be59 100644
--- a/drivers/usb/renesas_usbhs/mod_gadget.c
+++ b/drivers/usb/renesas_usbhs/mod_gadget.c
@@ -119,7 +119,7 @@ struct usbhsg_recip_handle {
/*
* queue push/pop
*/
-static void usbhsg_queue_pop(struct usbhsg_uep *uep,
+static void __usbhsg_queue_pop(struct usbhsg_uep *uep,
struct usbhsg_request *ureq,
int status)
{
@@ -133,6 +133,15 @@ static void usbhsg_queue_pop(struct usbhsg_uep *uep,
usb_gadget_giveback_request(uep-ep, ureq-req);
}
+static void usbhsg_queue_pop(struct usbhsg_uep *uep,
+ struct usbhsg_request *ureq,
+ int status)
+{
+ usbhs_lock(priv, flags);
+ __usbhsg_queue_pop(uep, ureq, status);
+ usbhs_unlock(priv, flags);
+}
+
static void usbhsg_queue_done(struct usbhs_priv *priv, struct usbhs_pkt *pkt)
{
struct usbhs_pipe *pipe = pkt-pipe;
then, for cases where lock is already held you call __usbhsg_queue_pop()
and for all other cases, call usbhsg_queue_pop().
Thank you for the suggestion. However, we cannot use this usbhsg_queue_pop()
because
a gadget driver might call usb_ep_queue() in the complete function and
this driver calls usbhs_lock() in the usb_ep_queue().
Perhaps my explanation was bad, but this issue was caused by the following
conditions:
- I use the renesas_usbhs driver as udc.
- I use an old usb-dmac driver that the callback runs on a kthread.
- I use the ncm driver. In this environment, the ncm driver might cause a
spinlock suspected.
As an old solution, I fixed the renesas_usbhs driver by this patch.
However, if I use a new usb-dmac driver that the callback runs on a tasklet,
I don't need this patch. (This is a new solution.)
Best regards,
Yoshihiro Shimoda
--
To unsubscribe from this list: send the line unsubscribe linux-usb in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [PATCH v2 1/4] usb: renesas_usbhs: fix spinlock suspected in a gadget complete function
Hi Geert-san,
Thank you for the reply again!
Hi Shimoda-san,
On Mon, Feb 16, 2015 at 2:52 AM, Yoshihiro Shimoda
yoshihiro.shimoda...@renesas.com wrote:
According to the gadget.h, a complete function will always be called
with interrupts disabled. However, sometimes usbhsg_queue_pop() function
is called with interrupts enabled. So, this function should calls
local_irq_save() before this calls the usb_gadget_giveback_request().
Otherwise, there is possible to cause a spinlock suspected in a gadget
complete function.
I still feel uneasy about adding the call to local_irq_save(), as the need for
this is usually an indicator of another locking problem.
I also think that I would like to avoid using local_irq_save().
But, I have no idea to resolve this issue for now.
Unfortunately I know next to nothing about the USB gadget subsystem, so some
help from the USB gadget experts would be appreciated.
I had a look at other drivers, and it seems most drivers actually release
and reacquire a spinlock around the call to usb_gadget_giveback_request(),
i.e. they do:
spin_unlock(...);
usb_gadget_giveback_request(...);
spin_lock();
This means they had already acquired the spinlock (and disabled interrupts!)
before, which looks much healthier to me.
There's only one driver that uses local_irq_save() (pxa27x_udc).
I had a look at the musb driver. It uses a dmaengine driver.
And, in the callback routine of the musb driver, it calls spin_lock_irqsave()
at first.
cppi41_dma_callback
-- spin_lock_irqsave(musb-lock, flags);
-- cppi41_trans_done
-- musb_dma_completion
-- musb_g_tx or musb_g_rx
-- musb_g_giveback
-- spin_unlock(musb-lock); # This means unlocked the spin, but
disabled interrupts.
-- usb_gadget_giveback_request
-- spin_lock(musb-lock);
snip
-- spin_unlock_irqrestore(musb-lock, flags);
So, about disabled interrupts before usb_gadget_giveback_request(),
it is similar with this patch.
Best regards,
Yoshihiro Shimoda
N�r��yb�X��ǧv�^�){.n�+{��^n�r���z���h��� �G���h�(�階�ݢj���m��z�ޖ���f���h���~�m�
Re: [PATCH v2 1/4] usb: renesas_usbhs: fix spinlock suspected in a gadget complete function
Hi Shimoda-san,
On Mon, Feb 16, 2015 at 2:52 AM, Yoshihiro Shimoda
yoshihiro.shimoda...@renesas.com wrote:
According to the gadget.h, a complete function will always be called
with interrupts disabled. However, sometimes usbhsg_queue_pop() function
is called with interrupts enabled. So, this function should calls
local_irq_save() before this calls the usb_gadget_giveback_request().
Otherwise, there is possible to cause a spinlock suspected in a gadget
complete function.
I still feel uneasy about adding the call to local_irq_save(), as the need for
this is usually an indicator of another locking problem.
Unfortunately I know next to nothing about the USB gadget subsystem, so some
help from the USB gadget experts would be appreciated.
I had a look at other drivers, and it seems most drivers actually release
and reacquire a spinlock around the call to usb_gadget_giveback_request(),
i.e. they do:
spin_unlock(...);
usb_gadget_giveback_request(...);
spin_lock();
This means they had already acquired the spinlock (and disabled interrupts!)
before, which looks much healthier to me.
There's only one driver that uses local_irq_save() (pxa27x_udc).
Signed-off-by: Yoshihiro Shimoda yoshihiro.shimoda...@renesas.com
---
drivers/usb/renesas_usbhs/mod_gadget.c | 11 +++
1 file changed, 11 insertions(+)
diff --git a/drivers/usb/renesas_usbhs/mod_gadget.c
b/drivers/usb/renesas_usbhs/mod_gadget.c
index e0384af..104bddf 100644
--- a/drivers/usb/renesas_usbhs/mod_gadget.c
+++ b/drivers/usb/renesas_usbhs/mod_gadget.c
@@ -126,11 +126,22 @@ static void usbhsg_queue_pop(struct usbhsg_uep *uep,
struct usbhsg_gpriv *gpriv = usbhsg_uep_to_gpriv(uep);
struct usbhs_pipe *pipe = usbhsg_uep_to_pipe(uep);
struct device *dev = usbhsg_gpriv_to_dev(gpriv);
+ unsigned long flags;
dev_dbg(dev, pipe %d : queue pop\n, usbhs_pipe_number(pipe));
ureq-req.status = status;
+ /*
+* According to the gadget.h, a complete function will always be
+* called with interrupts disabled. However, sometimes this function
+* is called with interrupts enabled. (e.g. complete a DMAC transfer
or
+* write data and done is set immediately when PIO.) So, this function
+* should calls local_irq_save() before this calls the
+* usb_gadget_giveback_request().
+*/
+ local_irq_save(flags);
usb_gadget_giveback_request(uep-ep, ureq-req);
+ local_irq_restore(flags);
}
static void usbhsg_queue_done(struct usbhs_priv *priv, struct usbhs_pkt *pkt)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say programmer or something like that.
-- Linus Torvalds
--
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[PATCH v2 1/4] usb: renesas_usbhs: fix spinlock suspected in a gadget complete function
According to the gadget.h, a complete function will always be called with interrupts disabled. However, sometimes usbhsg_queue_pop() function is called with interrupts enabled. So, this function should calls local_irq_save() before this calls the usb_gadget_giveback_request(). Otherwise, there is possible to cause a spinlock suspected in a gadget complete function. Signed-off-by: Yoshihiro Shimoda yoshihiro.shimoda...@renesas.com --- drivers/usb/renesas_usbhs/mod_gadget.c | 11 +++ 1 file changed, 11 insertions(+) diff --git a/drivers/usb/renesas_usbhs/mod_gadget.c b/drivers/usb/renesas_usbhs/mod_gadget.c index e0384af..104bddf 100644 --- a/drivers/usb/renesas_usbhs/mod_gadget.c +++ b/drivers/usb/renesas_usbhs/mod_gadget.c @@ -126,11 +126,22 @@ static void usbhsg_queue_pop(struct usbhsg_uep *uep, struct usbhsg_gpriv *gpriv = usbhsg_uep_to_gpriv(uep); struct usbhs_pipe *pipe = usbhsg_uep_to_pipe(uep); struct device *dev = usbhsg_gpriv_to_dev(gpriv); + unsigned long flags; dev_dbg(dev, pipe %d : queue pop\n, usbhs_pipe_number(pipe)); ureq-req.status = status; + /* +* According to the gadget.h, a complete function will always be +* called with interrupts disabled. However, sometimes this function +* is called with interrupts enabled. (e.g. complete a DMAC transfer or +* write data and done is set immediately when PIO.) So, this function +* should calls local_irq_save() before this calls the +* usb_gadget_giveback_request(). +*/ + local_irq_save(flags); usb_gadget_giveback_request(uep-ep, ureq-req); + local_irq_restore(flags); } static void usbhsg_queue_done(struct usbhs_priv *priv, struct usbhs_pkt *pkt) -- 1.7.9.5 -- To unsubscribe from this list: send the line unsubscribe linux-usb in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
