Re: Unhandled fault: imprecise external abort (0x1406) at 0x00000000 - PC is at xhci_hub_control

[Mathias Nyman]

On 10.5.2021 14.05, Naresh Kamboju wrote:
> On Mon, 10 May 2021 at 16:22, Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> wrote:
>>
>> On Mon, 10 May 2021 at 16:02, Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> wrote:
>>>
>>> The kernel crash reported on arm architecture BeagleBoard-X15 device running
>>> Linux next 5.13.0-rc1-next-20210510 while booting the device.
>>>
>>> [    4.956085] xhci-hcd xhci-hcd.1.auto: xHCI Host Controller
>>> [    4.961639] xhci-hcd xhci-hcd.1.auto: new USB bus registered,
>>> assigned bus number 2
>>> [    4.969360] xhci-hcd xhci-hcd.1.auto: Host supports USB 3.0 SuperSpeed
>>> [    4.976165] usb usb2: We don't know the algorithms for LPM for this
>>> host, disabling LPM.
>>> [    4.985321] hub 2-0:1.0: USB hub found
>>> [    4.989196] hub 2-0:1.0: 1 port detected
>>> [    5.002197] Waiting for root device
>>> PARTUUID=6b10e805-12ad-b44e-88b8-3abf3d5f52ed...
>>> [    5.022918] 8<--- cut here ---
>>> [    5.026000] Unhandled fault: imprecise external abort (0x1406) at 0x00000000
>>> [    5.033root
>>> 081] pgd = ff6a1748
>>> [    5.035797] [00000000] *pgd=00000000
>>> [    5.039398] Internal error: : 1406 [#1] SMP ARM
>>> [    5.043975] Modules linked in:
>>> [    5.047027] CPU: 0 PID: 22 Comm: kworker/0:1 Not tainted
>>> 5.13.0-rc1-next-20210510 #1
>>> [    5.054809] Hardware name: Generic DRA74X (Flattened Device Tree)
>>> [    5.060943] Workqueue: pm pm_runtime_work
>>> [    5.065002] PC is at xhci_hub_control+0xd00/0x248c
>>> [    5.069824] LR is at arm_heavy_mb+0x44/0x48
>>
>> Since, this crash is not easily reproducible I could bisect it.
> 
> sorry, i mean i could *not*
> 
> Since, this crash is not easily reproducible I could not bisect it.

Looks like USB SS roothub is trying to runtime suspend early during boot.

Any chance you could look up the source line of xhci_hub_control+0xd00/0x248c in your kernel?
gdb vmlinux
li *(xhci_hub_control+0xd00)

Thanks
-Mathias