Re: kernel: Alignment trap

From: JH <jupiter.hce@gmail.com>
To: Greg KH <greg@kroah.com>
Cc: linux-usb <linux-usb@vger.kernel.org>
Subject: Re: kernel: Alignment trap
Date: Thu, 21 Nov 2019 07:08:32 +1100	[thread overview]
Message-ID: <CAA=hcWQaXPWWAv2c9ZuVnPw-g075SC1tyKy0DP2+WrktdQYymg@mail.gmail.com> (raw)
In-Reply-To: <20191120133152.GB2892197@kroah.com>

Hi Greg,

On 11/21/19, Greg KH <greg@kroah.com> wrote:
> On Wed, Nov 20, 2019 at 09:28:14PM +1100, JH wrote:
>> Hi,
>>
>> I am running 4G LTE (USB protocol) and WiFi on IMX6 board, the kernel
>> is 4.19.75 LTE. It is not clear where the kernel alignment trap came
>> from, the only thing I could see is the alignment trap message
>> generated immediate after USB GSM communication or mwifiex_sdio. Where
>> that the alignment trap came from? Which parts of the program could
>> contribute the kernel alignment trap, kernel iteself, or USB GSM or
>> mwifiex_sdio? Appreciate clues how to fix it.
>>
>> Nov 20 05:08:09 solar kernel: usb 1-1: GSM modem (1-port) converter
>> now attached to ttyUSB0
>> Nov 20 05:08:09 solar kernel: option 1-1:1.2: GSM modem (1-port)
>> converter detected
>> Nov 20 05:08:09 solar kernel: usb 1-1: GSM modem (1-port) converter
>> now attached to ttyUSB1
>> Nov 20 05:08:10 solar kernel: mwifiex_sdio mmc0:0001:1: info: trying
>> to associate to 'Solar Analytics Wifi' bssid 78:8a:20:49:4b:c5
>> Nov 20 05:08:10 solar kernel: mwifiex_sdio mmc0:0001:1: info:
>> associated to bssid 78:8a:20:49:4b:c5 successfully
>> Nov 20 05:08:10 solar kernel: IPv6: ADDRCONF(NETDEV_CHANGE): mlan0:
>> link becomes ready
>> Nov 20 05:23:13 solar kernel: mwifiex_sdio mmc0:0001:1: info:
>> successfully disconnected from 78:8a:20:49:4b:c5: reason code 3
>> Nov 20 05:23:13 solar kernel: IPv6: ADDRCONF(NETDEV_UP): mlan0: link
>> is not ready
>> Nov 20 05:23:18 solar kernel: Alignment trap: not handling instruction
>> e8532f00 at [<b6c802b6>]
>> Nov 20 05:23:18 solar kernel: Unhandled fault: alignment exception
>> (0x001) at 0x38626667
>> Nov 20 05:23:18 solar kernel: pgd = 34bdb7e7
>> Nov 20 05:23:18 solar kernel: [38626667] *pgd=00000000
>
> You should have a much longer tracedump after this, right?  Can you
> provide that please?

That was the last statement from the kernel log journalctl -t kernel
-b at the time.

> And why do you think this was a USB issue?

No, I was not saying it was a USB issue, nor did I know if it is a
kernel issue or mwifiex_sdio issue or something else, I don't have the
knowledge to determine it, that was why I have to go this list for
help, I did try to connect to Linux network mailing list linux-net or
kernel mailing list lkml, but I must get wrong with the mailing list
address, I could not get response or subscription frin linux-net or
lkml, if you could let me know the correct kernel network mailing
address and kernel mailing list address, I'll ask the help there as
well.

Thanks Greg.

- jh