Re: [PATCH v3] usb: dwc3: gadget: Prevent EP queuing while stopping transfers

[Andy Shevchenko <andy.shevchenko@gmail.com>]

On Tue, Mar 23, 2021 at 1:19 AM Wesley Cheng <wcheng@codeaurora.org> wrote:
>
> Hi Andy,
>
> On 3/22/2021 2:14 PM, Andy Shevchenko wrote:
> > On Mon, Mar 22, 2021 at 10:06 PM Wesley Cheng <wcheng@codeaurora.org> wrote:
> >>
> >> Hi Andy,
> >>
> >> On 3/22/2021 12:34 PM, Andy Shevchenko wrote:
> >>> On Mon, Mar 22, 2021 at 8:49 PM Wesley Cheng <wcheng@codeaurora.org> wrote:
> >>>>
> >>>> Hi Andy,
> >>>>
> >>>> On 3/22/2021 5:48 AM, Andy Shevchenko wrote:
> >>>>> On Fri, Mar 12, 2021 at 2:01 AM Wesley Cheng <wcheng@codeaurora.org> wrote:
> >>>>>>
> >>>>>> In the situations where the DWC3 gadget stops active transfers, once
> >>>>>> calling the dwc3_gadget_giveback(), there is a chance where a function
> >>>>>> driver can queue a new USB request in between the time where the dwc3
> >>>>>> lock has been released and re-aquired.  This occurs after we've already
> >>>>>> issued an ENDXFER command.  When the stop active transfers continues
> >>>>>> to remove USB requests from all dep lists, the newly added request will
> >>>>>> also be removed, while controller still has an active TRB for it.
> >>>>>> This can lead to the controller accessing an unmapped memory address.
> >>>>>>
> >>>>>> Fix this by ensuring parameters to prevent EP queuing are set before
> >>>>>> calling the stop active transfers API.
> >>>>>
> >>>>>
> >>>>> commit f09ddcfcb8c569675066337adac2ac205113471f
> >>>>> Author: Wesley Cheng <wcheng@codeaurora.org>
> >>>>> Date:   Thu Mar 11 15:59:02 2021 -0800
> >>>>>
> >>>>>    usb: dwc3: gadget: Prevent EP queuing while stopping transfers
> >>>>>
> >>>>> effectively broke my gadget setup.
> >>>>>
> >>>>> The output of the kernel (followed by non responsive state of USB controller):
> >>>>>
> >>>>> [  195.228586] using random self ethernet address
> >>>>> [  195.233104] using random host ethernet address
> >>>>> [  195.245306] usb0: HOST MAC aa:bb:cc:dd:ee:f2
> >>>>> [  195.249732] usb0: MAC aa:bb:cc:dd:ee:f1
> >>>>> # [  195.773594] IPv6: ADDRCONF(NETDEV_CHANGE): usb0: link becomes ready
> >>>>> [  195.780585] ------------[ cut here ]------------
> >>>>> [  195.785217] dwc3 dwc3.0.auto: No resource for ep2in
> >>>>> [  195.790162] WARNING: CPU: 0 PID: 217 at
> >>>>> drivers/usb/dwc3/gadget.c:360 dwc3_send_gadget_ep_cmd+0x4b9/0x670
> >>>>> [  195.799760] Modules linked in: usb_f_eem u_ether libcomposite
> >>>>> brcmfmac brcmutil mmc_block pwm_lpss_pci pwm_lps
> >>>>> s snd_sof_pci_intel_tng snd_sof_pci snd_sof_acpi_intel_byt
> >>>>> snd_sof_intel_ipc snd_sof_acpi snd_sof snd_sof_nocodec
> >>>>> spi_pxa2xx_platform snd_sof_xtensa_dsp spi_pxa2xx_pci
> >>>>> extcon_intel_mrfld intel_mrfld_adc sdhci_pci cqhci sdhci m
> >>>>> mc_core intel_mrfld_pwrbtn intel_soc_pmic_mrfld hci_uart btbcm btintel
> >>>>> [  195.835604] CPU: 0 PID: 217 Comm: irq/16-dwc3 Not tainted 5.12.0-rc4+ #60
> >>>>> [  195.842403] Hardware name: Intel Corporation Merrifield/BODEGA BAY,
> >>>>> BIOS 542 2015.01.21:18.19.48
> >>>>> [  195.851191] RIP: 0010:dwc3_send_gadget_ep_cmd+0x4b9/0x670
> >>>>> [  195.856608] Code: cd 00 00 00 44 89 44 24 20 48 89 4c 24 18 e8 ee
> >>>>> f7 e4 ff 48 8b 4c 24 18 4c 89 f2 48 c7 c7 b9
> >>>>> ed 4f a0 48 89 c6 e8 ef 24 43 00 <0f> 0b 41 be ea ff ff ff 44 8b 44 24
> >>>>> 20 e9 80 fc ff ff 41 83 fe 92
> >>>>> [  195.875381] RSP: 0000:ffffa53c00373ba8 EFLAGS: 00010086
> >>>>> [  195.880617] RAX: 0000000000000000 RBX: 0000000000001387 RCX: 00000000ffffdfff
> >>>>> [  195.887755] RDX: 00000000ffffdfff RSI: 00000000ffffffea RDI: 0000000000000000
> >>>>> [  195.894893] RBP: ffff9ce8c8f2b028 R08: ffffffffa0732288 R09: 0000000000009ffb
> >>>>> [  195.902034] R10: 00000000ffffe000 R11: 3fffffffffffffff R12: 0000000000041006
> >>>>> [  195.909170] R13: ffffa53c00373c24 R14: ffff9ce8c11dadb0 R15: ffff9ce8c2861700
> >>>>> [  195.916310] FS:  0000000000000000(0000) GS:ffff9ce8fe200000(0000)
> >>>>> knlGS:0000000000000000
> >>>>> [  195.924409] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >>>>> [  195.930161] CR2: 00000000f7f694a0 CR3: 0000000038e0c000 CR4: 00000000001006f0
> >>>>> [  195.937300] Call Trace:
> >>>>> [  195.939755]  __dwc3_gadget_ep_enable+0x2d4/0x4e0
> >>>>> [  195.944393]  ? dwc3_remove_requests.constprop.0+0x86/0x170
> >>>>
> >>>> Odd that this change would affect the USB enablment path, as they were
> >>>> focused on the pullup disable path.  Would you happen to have any
> >>>> downstream changes on top of v5.12-rc4 we could review to see if they
> >>>> are still required? (ie where is the dwc3_remove_requests() coming from
> >>>> during ep enable)
> >>>
> >>> You may check my branch [1] on GH. Basically you may be interested in
> >>> the commit:
> >>> 0f86df1294ee7523060cc16eafaf4898c693eab0 REVERTME: usb: dwc3: gadget:
> >>> skip endpoints ep[18]{in,out}
> >>> Otherwise it's a clean v5.12-rc4 with a revert and another USB PHY
> >>> suspend fix (which also shouldn't affect this).
> >>
> >> Can you link your GH reference?
> >
> > Oops, sorry.
> > Here we are:
> >
> > [1]: https://github.com/andy-shev/linux/tree/eds-acpi
> >
> Thanks, I took a look and even tried it on my device running 5.12-rc4,
> but wasn't able to see the same problem.  Could you help collect the
> ftrace after enabling the tracing KCONFIG and running the below sequence?
>
> 1.  Mount debugfs
> 2.  Set up tracing instance
>
> mkdir /sys/kernel/debug/tracing/instances/usb
> echo 1 >
> /sys/kernel/debug/tracing/instances/usb/events/dwc3/dwc3_complete_trb/enable
> echo 1 >
> /sys/kernel/debug/tracing/instances/usb/events/dwc3/dwc3_ctrl_req/enable
> echo 1 >
> /sys/kernel/debug/tracing/instances/usb/events/dwc3/dwc3_ep_dequeue/enable
> echo 1 >
> /sys/kernel/debug/tracing/instances/usb/events/dwc3/dwc3_ep_queue/enable
> echo 1 >
> /sys/kernel/debug/tracing/instances/usb/events/dwc3/dwc3_gadget_ep_cmd/enable
> echo 1 >
> /sys/kernel/debug/tracing/instances/usb/events/dwc3/dwc3_gadget_ep_disable/enable
> echo 1 >
> /sys/kernel/debug/tracing/instances/usb/events/dwc3/dwc3_gadget_ep_enable/enable
> echo 1 >
> /sys/kernel/debug/tracing/instances/usb/events/dwc3/dwc3_gadget_giveback/enable
> echo 1 >
> /sys/kernel/debug/tracing/instances/usb/events/dwc3/dwc3_prepare_trb/enable
> echo 1 > /sys/kernel/debug/tracing/instances/usb/tracing_on
>
> 3.  Run your test, which should include:
>         - echo "" > /sys/kernel/config/usb_gadget/g1/UDC
>         - echo <UDC name> > /sys/kernel/config/usb_gadget/g1/UDC
>
> 4.  Collect the trace output:
> cat /sys/kernel/debug/tracing/instances/usb/trace

Here we are (I cherry-picked again reverted patch, other stays the same) [2].
On top I put a warning, so you may see timestamps.

Dunno how long it will stay there, please confirm that you got it.

[2]: https://paste.ubuntu.com/p/jNF565ypPp/

-- 
With Best Regards,
Andy Shevchenko