2024-01-19 09:49:09

by Uttkarsh Aggarwal

[permalink] [raw]
Subject: [PATCH v3] usb: dwc3: gadget: Fix NULL pointer dereference in dwc3_gadget_suspend

In current scenario if Plug-out and Plug-In performed continuously
there could be a chance while checking for dwc->gadget_driver in
dwc3_gadget_suspend, a NULL pointer dereference may occur.

Call Stack:

CPU1: CPU2:
gadget_unbind_driver dwc3_suspend_common
dwc3_gadget_stop dwc3_gadget_suspend
dwc3_disconnect_gadget

CPU1 basically clears the variable and CPU2 checks the variable.
Consider CPU1 is running and right before gadget_driver is cleared
and in parallel CPU2 executes dwc3_gadget_suspend where it finds
dwc->gadget_driver which is not NULL and resumes execution and then
CPU1 completes execution. CPU2 executes dwc3_disconnect_gadget where
it checks dwc->gadget_driver is already NULL because of which the
NULL pointer deference occur.

Cc: <[email protected]>
Fixes: 9772b47a4c29 ("usb: dwc3: gadget: Fix suspend/resume during device mode")
Acked-by: Thinh Nguyen <[email protected]>
Signed-off-by: Uttkarsh Aggarwal <[email protected]>
---

changes in v3:
Corrected fixes tag and typo mistake in commit message dw3_gadget_stop -> dwc3_gadget_stop.

Link to v2:
https://lore.kernel.org/linux-usb/CAKzKK0r8RUqgXy1o5dndU21KuTKtyZ5rn5Fb9sZqTPZqAjT_9A@mail.gmail.com/T/#t

Changes in v2:
Added cc and fixes tag missing in v1.

Link to v1:
https://lore.kernel.org/linux-usb/[email protected]/T/#u

drivers/usb/dwc3/gadget.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 019368f8e9c4..564976b3e2b9 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -4709,15 +4709,13 @@ int dwc3_gadget_suspend(struct dwc3 *dwc)
unsigned long flags;
int ret;

- if (!dwc->gadget_driver)
- return 0;
-
ret = dwc3_gadget_soft_disconnect(dwc);
if (ret)
goto err;

spin_lock_irqsave(&dwc->lock, flags);
- dwc3_disconnect_gadget(dwc);
+ if (dwc->gadget_driver)
+ dwc3_disconnect_gadget(dwc);
spin_unlock_irqrestore(&dwc->lock, flags);

return 0;
--
2.17.1



2024-02-07 12:02:05

by Marek Szyprowski

[permalink] [raw]
Subject: Re: [PATCH v3] usb: dwc3: gadget: Fix NULL pointer dereference in dwc3_gadget_suspend

Dear All,

On 19.01.2024 10:48, Uttkarsh Aggarwal wrote:
> In current scenario if Plug-out and Plug-In performed continuously
> there could be a chance while checking for dwc->gadget_driver in
> dwc3_gadget_suspend, a NULL pointer dereference may occur.
>
> Call Stack:
>
> CPU1: CPU2:
> gadget_unbind_driver dwc3_suspend_common
> dwc3_gadget_stop dwc3_gadget_suspend
> dwc3_disconnect_gadget
>
> CPU1 basically clears the variable and CPU2 checks the variable.
> Consider CPU1 is running and right before gadget_driver is cleared
> and in parallel CPU2 executes dwc3_gadget_suspend where it finds
> dwc->gadget_driver which is not NULL and resumes execution and then
> CPU1 completes execution. CPU2 executes dwc3_disconnect_gadget where
> it checks dwc->gadget_driver is already NULL because of which the
> NULL pointer deference occur.
>
> Cc: <[email protected]>
> Fixes: 9772b47a4c29 ("usb: dwc3: gadget: Fix suspend/resume during device mode")
> Acked-by: Thinh Nguyen <[email protected]>
> Signed-off-by: Uttkarsh Aggarwal <[email protected]>

This patch landed some time ago in linux-next as commit 61a348857e86
("usb: dwc3: gadget: Fix NULL pointer dereference in
dwc3_gadget_suspend"). Recently I found that it causes the following
warning when no USB gadget is bound to the DWC3 driver and a system
suspend/resume cycle is performed:

dwc3 12400000.usb: wait for SETUP phase timed out
dwc3 12400000.usb: failed to set STALL on ep0out
------------[ cut here ]------------
WARNING: CPU: 4 PID: 604 at drivers/usb/dwc3/ep0.c:289
dwc3_ep0_out_start+0xc8/0xcc
Modules linked in:
CPU: 4 PID: 604 Comm: rtcwake Not tainted 6.8.0-rc3-next-20240207 #7979
Hardware name: Samsung Exynos (Flattened Device Tree)
 unwind_backtrace from show_stack+0x10/0x14
 show_stack from dump_stack_lvl+0x58/0x70
 dump_stack_lvl from __warn+0x7c/0x1bc
 __warn from warn_slowpath_fmt+0x1a0/0x1a8
 warn_slowpath_fmt from dwc3_ep0_out_start+0xc8/0xcc
 dwc3_ep0_out_start from dwc3_gadget_soft_disconnect+0x16c/0x230
 dwc3_gadget_soft_disconnect from dwc3_gadget_suspend+0xc/0x90
 dwc3_gadget_suspend from dwc3_suspend_common+0x44/0x30c
 dwc3_suspend_common from dwc3_suspend+0x14/0x2c
 dwc3_suspend from dpm_run_callback+0x94/0x288
 dpm_run_callback from device_suspend+0x130/0x6d0
 device_suspend from dpm_suspend+0x124/0x35c
 dpm_suspend from dpm_suspend_start+0x64/0x6c
 dpm_suspend_start from suspend_devices_and_enter+0x134/0xbd8
 suspend_devices_and_enter from pm_suspend+0x2ec/0x380
 pm_suspend from state_store+0x68/0xc8
 state_store from kernfs_fop_write_iter+0x110/0x1d4
 kernfs_fop_write_iter from vfs_write+0x2e8/0x430
 vfs_write from ksys_write+0x5c/0xd4
 ksys_write from ret_fast_syscall+0x0/0x1c
Exception stack(0xf1421fa8 to 0xf1421ff0)
..
irq event stamp: 14304
hardirqs last  enabled at (14303): [<c01a599c>] console_unlock+0x108/0x114
hardirqs last disabled at (14304): [<c0c229d8>]
_raw_spin_lock_irqsave+0x64/0x68
softirqs last  enabled at (13030): [<c010163c>] __do_softirq+0x318/0x4f4
softirqs last disabled at (13025): [<c012dd40>] __irq_exit_rcu+0x130/0x184
---[ end trace 0000000000000000 ]---

IMHO dwc3_gadget_soft_disconnect() requires some kind of a check if
dwc->gadget_driver is present or not, as it really makes no sense to do
any ep0 related operations if there is no gadget driver at all.


> ---
>
> changes in v3:
> Corrected fixes tag and typo mistake in commit message dw3_gadget_stop -> dwc3_gadget_stop.
>
> Link to v2:
> https://lore.kernel.org/linux-usb/CAKzKK0r8RUqgXy1o5dndU21KuTKtyZ5rn5Fb9sZqTPZqAjT_9A@mail.gmail.com/T/#t
>
> Changes in v2:
> Added cc and fixes tag missing in v1.
>
> Link to v1:
> https://lore.kernel.org/linux-usb/[email protected]/T/#u
>
> drivers/usb/dwc3/gadget.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 019368f8e9c4..564976b3e2b9 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -4709,15 +4709,13 @@ int dwc3_gadget_suspend(struct dwc3 *dwc)
> unsigned long flags;
> int ret;
>
> - if (!dwc->gadget_driver)
> - return 0;
> -
> ret = dwc3_gadget_soft_disconnect(dwc);
> if (ret)
> goto err;
>
> spin_lock_irqsave(&dwc->lock, flags);
> - dwc3_disconnect_gadget(dwc);
> + if (dwc->gadget_driver)
> + dwc3_disconnect_gadget(dwc);
> spin_unlock_irqrestore(&dwc->lock, flags);
>
> return 0;

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland


2024-02-08 22:56:42

by Thinh Nguyen

[permalink] [raw]
Subject: Re: [PATCH v3] usb: dwc3: gadget: Fix NULL pointer dereference in dwc3_gadget_suspend

On Wed, Feb 07, 2024, Marek Szyprowski wrote:
> Dear All,
>
> On 19.01.2024 10:48, Uttkarsh Aggarwal wrote:
> > In current scenario if Plug-out and Plug-In performed continuously
> > there could be a chance while checking for dwc->gadget_driver in
> > dwc3_gadget_suspend, a NULL pointer dereference may occur.
> >
> > Call Stack:
> >
> > CPU1: CPU2:
> > gadget_unbind_driver dwc3_suspend_common
> > dwc3_gadget_stop dwc3_gadget_suspend
> > dwc3_disconnect_gadget
> >
> > CPU1 basically clears the variable and CPU2 checks the variable.
> > Consider CPU1 is running and right before gadget_driver is cleared
> > and in parallel CPU2 executes dwc3_gadget_suspend where it finds
> > dwc->gadget_driver which is not NULL and resumes execution and then
> > CPU1 completes execution. CPU2 executes dwc3_disconnect_gadget where
> > it checks dwc->gadget_driver is already NULL because of which the
> > NULL pointer deference occur.
> >
> > Cc: <[email protected]>
> > Fixes: 9772b47a4c29 ("usb: dwc3: gadget: Fix suspend/resume during device mode")
> > Acked-by: Thinh Nguyen <[email protected]>
> > Signed-off-by: Uttkarsh Aggarwal <[email protected]>
>
> This patch landed some time ago in linux-next as commit 61a348857e86
> ("usb: dwc3: gadget: Fix NULL pointer dereference in
> dwc3_gadget_suspend"). Recently I found that it causes the following
> warning when no USB gadget is bound to the DWC3 driver and a system
> suspend/resume cycle is performed:
>
> dwc3 12400000.usb: wait for SETUP phase timed out
> dwc3 12400000.usb: failed to set STALL on ep0out
> ------------[ cut here ]------------
> WARNING: CPU: 4 PID: 604 at drivers/usb/dwc3/ep0.c:289
> dwc3_ep0_out_start+0xc8/0xcc
> Modules linked in:
> CPU: 4 PID: 604 Comm: rtcwake Not tainted 6.8.0-rc3-next-20240207 #7979
> Hardware name: Samsung Exynos (Flattened Device Tree)
>  unwind_backtrace from show_stack+0x10/0x14
>  show_stack from dump_stack_lvl+0x58/0x70
>  dump_stack_lvl from __warn+0x7c/0x1bc
>  __warn from warn_slowpath_fmt+0x1a0/0x1a8
>  warn_slowpath_fmt from dwc3_ep0_out_start+0xc8/0xcc
>  dwc3_ep0_out_start from dwc3_gadget_soft_disconnect+0x16c/0x230
>  dwc3_gadget_soft_disconnect from dwc3_gadget_suspend+0xc/0x90
>  dwc3_gadget_suspend from dwc3_suspend_common+0x44/0x30c
>  dwc3_suspend_common from dwc3_suspend+0x14/0x2c
>  dwc3_suspend from dpm_run_callback+0x94/0x288
>  dpm_run_callback from device_suspend+0x130/0x6d0
>  device_suspend from dpm_suspend+0x124/0x35c
>  dpm_suspend from dpm_suspend_start+0x64/0x6c
>  dpm_suspend_start from suspend_devices_and_enter+0x134/0xbd8
>  suspend_devices_and_enter from pm_suspend+0x2ec/0x380
>  pm_suspend from state_store+0x68/0xc8
>  state_store from kernfs_fop_write_iter+0x110/0x1d4
>  kernfs_fop_write_iter from vfs_write+0x2e8/0x430
>  vfs_write from ksys_write+0x5c/0xd4
>  ksys_write from ret_fast_syscall+0x0/0x1c
> Exception stack(0xf1421fa8 to 0xf1421ff0)
> ...
> irq event stamp: 14304
> hardirqs last  enabled at (14303): [<c01a599c>] console_unlock+0x108/0x114
> hardirqs last disabled at (14304): [<c0c229d8>]
> _raw_spin_lock_irqsave+0x64/0x68
> softirqs last  enabled at (13030): [<c010163c>] __do_softirq+0x318/0x4f4
> softirqs last disabled at (13025): [<c012dd40>] __irq_exit_rcu+0x130/0x184
> ---[ end trace 0000000000000000 ]---
>
> IMHO dwc3_gadget_soft_disconnect() requires some kind of a check if
> dwc->gadget_driver is present or not, as it really makes no sense to do

I don't think checking that is sufficient, and I don't think that's the
case here.

> any ep0 related operations if there is no gadget driver at all.
>

If there's indeed no gadget_driver present, then we wouldn't get this
stack trace. (ie. dwc3_ep0_out_start should occurs when gadget_driver is
present). This is a race happened between binding + suspend.

I think something like this should be sufficient. Would you mind giving
it a try?

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 564976b3e2b9..1990d6371066 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2656,6 +2656,11 @@ static int dwc3_gadget_soft_disconnect(struct dwc3 *dwc)
int ret;

spin_lock_irqsave(&dwc->lock, flags);
+ if (!dwc->pullups_connected) {
+ spin_unlock_irqrestore(&dwc->lock, flags);
+ return 0;
+ }
+
dwc->connected = false;

/*


Thanks,
Thinh

2024-02-09 09:41:45

by Marek Szyprowski

[permalink] [raw]
Subject: Re: [PATCH v3] usb: dwc3: gadget: Fix NULL pointer dereference in dwc3_gadget_suspend

On 08.02.2024 23:54, Thinh Nguyen wrote:
> On Wed, Feb 07, 2024, Marek Szyprowski wrote:
>> On 19.01.2024 10:48, Uttkarsh Aggarwal wrote:
>>> In current scenario if Plug-out and Plug-In performed continuously
>>> there could be a chance while checking for dwc->gadget_driver in
>>> dwc3_gadget_suspend, a NULL pointer dereference may occur.
>>>
>>> Call Stack:
>>>
>>> CPU1: CPU2:
>>> gadget_unbind_driver dwc3_suspend_common
>>> dwc3_gadget_stop dwc3_gadget_suspend
>>> dwc3_disconnect_gadget
>>>
>>> CPU1 basically clears the variable and CPU2 checks the variable.
>>> Consider CPU1 is running and right before gadget_driver is cleared
>>> and in parallel CPU2 executes dwc3_gadget_suspend where it finds
>>> dwc->gadget_driver which is not NULL and resumes execution and then
>>> CPU1 completes execution. CPU2 executes dwc3_disconnect_gadget where
>>> it checks dwc->gadget_driver is already NULL because of which the
>>> NULL pointer deference occur.
>>>
>>> Cc: <[email protected]>
>>> Fixes: 9772b47a4c29 ("usb: dwc3: gadget: Fix suspend/resume during device mode")
>>> Acked-by: Thinh Nguyen <[email protected]>
>>> Signed-off-by: Uttkarsh Aggarwal <[email protected]>
>> This patch landed some time ago in linux-next as commit 61a348857e86
>> ("usb: dwc3: gadget: Fix NULL pointer dereference in
>> dwc3_gadget_suspend"). Recently I found that it causes the following
>> warning when no USB gadget is bound to the DWC3 driver and a system
>> suspend/resume cycle is performed:
>>
>> dwc3 12400000.usb: wait for SETUP phase timed out
>> dwc3 12400000.usb: failed to set STALL on ep0out
>> ------------[ cut here ]------------
>> WARNING: CPU: 4 PID: 604 at drivers/usb/dwc3/ep0.c:289
>> dwc3_ep0_out_start+0xc8/0xcc
>> Modules linked in:
>> CPU: 4 PID: 604 Comm: rtcwake Not tainted 6.8.0-rc3-next-20240207 #7979
>> Hardware name: Samsung Exynos (Flattened Device Tree)
>>  unwind_backtrace from show_stack+0x10/0x14
>>  show_stack from dump_stack_lvl+0x58/0x70
>>  dump_stack_lvl from __warn+0x7c/0x1bc
>>  __warn from warn_slowpath_fmt+0x1a0/0x1a8
>>  warn_slowpath_fmt from dwc3_ep0_out_start+0xc8/0xcc
>>  dwc3_ep0_out_start from dwc3_gadget_soft_disconnect+0x16c/0x230
>>  dwc3_gadget_soft_disconnect from dwc3_gadget_suspend+0xc/0x90
>>  dwc3_gadget_suspend from dwc3_suspend_common+0x44/0x30c
>>  dwc3_suspend_common from dwc3_suspend+0x14/0x2c
>>  dwc3_suspend from dpm_run_callback+0x94/0x288
>>  dpm_run_callback from device_suspend+0x130/0x6d0
>>  device_suspend from dpm_suspend+0x124/0x35c
>>  dpm_suspend from dpm_suspend_start+0x64/0x6c
>>  dpm_suspend_start from suspend_devices_and_enter+0x134/0xbd8
>>  suspend_devices_and_enter from pm_suspend+0x2ec/0x380
>>  pm_suspend from state_store+0x68/0xc8
>>  state_store from kernfs_fop_write_iter+0x110/0x1d4
>>  kernfs_fop_write_iter from vfs_write+0x2e8/0x430
>>  vfs_write from ksys_write+0x5c/0xd4
>>  ksys_write from ret_fast_syscall+0x0/0x1c
>> Exception stack(0xf1421fa8 to 0xf1421ff0)
>> ...
>> irq event stamp: 14304
>> hardirqs last  enabled at (14303): [<c01a599c>] console_unlock+0x108/0x114
>> hardirqs last disabled at (14304): [<c0c229d8>]
>> _raw_spin_lock_irqsave+0x64/0x68
>> softirqs last  enabled at (13030): [<c010163c>] __do_softirq+0x318/0x4f4
>> softirqs last disabled at (13025): [<c012dd40>] __irq_exit_rcu+0x130/0x184
>> ---[ end trace 0000000000000000 ]---
>>
>> IMHO dwc3_gadget_soft_disconnect() requires some kind of a check if
>> dwc->gadget_driver is present or not, as it really makes no sense to do
> I don't think checking that is sufficient, and I don't think that's the
> case here.
>
>> any ep0 related operations if there is no gadget driver at all.
>>
> If there's indeed no gadget_driver present, then we wouldn't get this
> stack trace. (ie. dwc3_ep0_out_start should occurs when gadget_driver is
> present). This is a race happened between binding + suspend.

I have no gadget compiled into the kernel and no such created via
configfs, so how can this be caused by a race?



> I think something like this should be sufficient. Would you mind giving
> it a try?
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 564976b3e2b9..1990d6371066 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -2656,6 +2656,11 @@ static int dwc3_gadget_soft_disconnect(struct dwc3 *dwc)
> int ret;
>
> spin_lock_irqsave(&dwc->lock, flags);
> + if (!dwc->pullups_connected) {
> + spin_unlock_irqrestore(&dwc->lock, flags);
> + return 0;
> + }
> +
> dwc->connected = false;
>
> /*
>
This patch fixes the reported issue. Feel free to add:

Tested-by: Marek Szyprowski <[email protected]>


Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland


2024-02-15 23:36:33

by Thinh Nguyen

[permalink] [raw]
Subject: Re: [PATCH v3] usb: dwc3: gadget: Fix NULL pointer dereference in dwc3_gadget_suspend

Sorry for the late reply.

On Fri, Feb 09, 2024, Marek Szyprowski wrote:
> On 08.02.2024 23:54, Thinh Nguyen wrote:
> > On Wed, Feb 07, 2024, Marek Szyprowski wrote:
> >> On 19.01.2024 10:48, Uttkarsh Aggarwal wrote:
> >>> In current scenario if Plug-out and Plug-In performed continuously
> >>> there could be a chance while checking for dwc->gadget_driver in
> >>> dwc3_gadget_suspend, a NULL pointer dereference may occur.
> >>>
> >>> Call Stack:
> >>>
> >>> CPU1: CPU2:
> >>> gadget_unbind_driver dwc3_suspend_common
> >>> dwc3_gadget_stop dwc3_gadget_suspend
> >>> dwc3_disconnect_gadget
> >>>
> >>> CPU1 basically clears the variable and CPU2 checks the variable.
> >>> Consider CPU1 is running and right before gadget_driver is cleared
> >>> and in parallel CPU2 executes dwc3_gadget_suspend where it finds
> >>> dwc->gadget_driver which is not NULL and resumes execution and then
> >>> CPU1 completes execution. CPU2 executes dwc3_disconnect_gadget where
> >>> it checks dwc->gadget_driver is already NULL because of which the
> >>> NULL pointer deference occur.
> >>>
> >>> Cc: <[email protected]>
> >>> Fixes: 9772b47a4c29 ("usb: dwc3: gadget: Fix suspend/resume during device mode")
> >>> Acked-by: Thinh Nguyen <[email protected]>
> >>> Signed-off-by: Uttkarsh Aggarwal <[email protected]>
> >> This patch landed some time ago in linux-next as commit 61a348857e86
> >> ("usb: dwc3: gadget: Fix NULL pointer dereference in
> >> dwc3_gadget_suspend"). Recently I found that it causes the following
> >> warning when no USB gadget is bound to the DWC3 driver and a system
> >> suspend/resume cycle is performed:
> >>
> >> dwc3 12400000.usb: wait for SETUP phase timed out
> >> dwc3 12400000.usb: failed to set STALL on ep0out
> >> ------------[ cut here ]------------
> >> WARNING: CPU: 4 PID: 604 at drivers/usb/dwc3/ep0.c:289
> >> dwc3_ep0_out_start+0xc8/0xcc
> >> Modules linked in:
> >> CPU: 4 PID: 604 Comm: rtcwake Not tainted 6.8.0-rc3-next-20240207 #7979
> >> Hardware name: Samsung Exynos (Flattened Device Tree)
> >>  unwind_backtrace from show_stack+0x10/0x14
> >>  show_stack from dump_stack_lvl+0x58/0x70
> >>  dump_stack_lvl from __warn+0x7c/0x1bc
> >>  __warn from warn_slowpath_fmt+0x1a0/0x1a8
> >>  warn_slowpath_fmt from dwc3_ep0_out_start+0xc8/0xcc
> >>  dwc3_ep0_out_start from dwc3_gadget_soft_disconnect+0x16c/0x230
> >>  dwc3_gadget_soft_disconnect from dwc3_gadget_suspend+0xc/0x90
> >>  dwc3_gadget_suspend from dwc3_suspend_common+0x44/0x30c
> >>  dwc3_suspend_common from dwc3_suspend+0x14/0x2c
> >>  dwc3_suspend from dpm_run_callback+0x94/0x288
> >>  dpm_run_callback from device_suspend+0x130/0x6d0
> >>  device_suspend from dpm_suspend+0x124/0x35c
> >>  dpm_suspend from dpm_suspend_start+0x64/0x6c
> >>  dpm_suspend_start from suspend_devices_and_enter+0x134/0xbd8
> >>  suspend_devices_and_enter from pm_suspend+0x2ec/0x380
> >>  pm_suspend from state_store+0x68/0xc8
> >>  state_store from kernfs_fop_write_iter+0x110/0x1d4
> >>  kernfs_fop_write_iter from vfs_write+0x2e8/0x430
> >>  vfs_write from ksys_write+0x5c/0xd4
> >>  ksys_write from ret_fast_syscall+0x0/0x1c
> >> Exception stack(0xf1421fa8 to 0xf1421ff0)
> >> ...
> >> irq event stamp: 14304
> >> hardirqs last  enabled at (14303): [<c01a599c>] console_unlock+0x108/0x114
> >> hardirqs last disabled at (14304): [<c0c229d8>]
> >> _raw_spin_lock_irqsave+0x64/0x68
> >> softirqs last  enabled at (13030): [<c010163c>] __do_softirq+0x318/0x4f4
> >> softirqs last disabled at (13025): [<c012dd40>] __irq_exit_rcu+0x130/0x184
> >> ---[ end trace 0000000000000000 ]---
> >>
> >> IMHO dwc3_gadget_soft_disconnect() requires some kind of a check if
> >> dwc->gadget_driver is present or not, as it really makes no sense to do
> > I don't think checking that is sufficient, and I don't think that's the
> > case here.
> >
> >> any ep0 related operations if there is no gadget driver at all.
> >>
> > If there's indeed no gadget_driver present, then we wouldn't get this
> > stack trace. (ie. dwc3_ep0_out_start should occurs when gadget_driver is
> > present). This is a race happened between binding + suspend.
>
> I have no gadget compiled into the kernel and no such created via
> configfs, so how can this be caused by a race?

Ah... In that case, we got through the incomplete/wrong check for
dwc3_gadget_soft_disconnect():
if (dwc->ep0state != EP0_SETUP_PHASE)

Since there's no gadget driver, the controller never started and the
ep0state is defaulted to EP0_UNCONNECTED, which explained why it got
into the timeout condition above and incorrectly attempt to start the
control transfer.

>
>
>
> > I think something like this should be sufficient. Would you mind giving
> > it a try?
> >
> > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> > index 564976b3e2b9..1990d6371066 100644
> > --- a/drivers/usb/dwc3/gadget.c
> > +++ b/drivers/usb/dwc3/gadget.c
> > @@ -2656,6 +2656,11 @@ static int dwc3_gadget_soft_disconnect(struct dwc3 *dwc)
> > int ret;
> >
> > spin_lock_irqsave(&dwc->lock, flags);
> > + if (!dwc->pullups_connected) {
> > + spin_unlock_irqrestore(&dwc->lock, flags);
> > + return 0;
> > + }
> > +
> > dwc->connected = false;
> >
> > /*
> >
> This patch fixes the reported issue. Feel free to add:
>
> Tested-by: Marek Szyprowski <[email protected]>
>

Thanks for the report and Tested-by! I'll send a fix patch soon.

BR,
Thinh