On 7/4/20 11:36 AM, Greg KH wrote
Thanks for your quick reply, Greg.
Where is the kernel crash in those logs? I don't seem to be able to
find the correct one, can you just send it here so we can read and
comment on it in the email thread? I see something odd with the fat
driver, are you sure you are creating a correct filesystem image for it
to handle?
There are two crashes described in that report. In the first post, I
mentioned that the full kdump crash dump is here:
https://drive.google.com/open?id=1ka3ySSccEMRSmnYgI9X16IndPDmIKTD6
Is that what you are looking for?
The first trace seems USB-related, and is in comment #2 (you have to
click Read More...),
and starts out:
[76707.692760] Call Trace:
[76707.692767] ? usb_alloc_urb+0x29/0x60
[76707.692772] usb_alloc_urb+0x29/0x60
[76707.692779] acm_probe+0x6da/0xdb0 [cdc_acm]
...
The second trace is in comment #4, and seems filesystem-related:
[40866.349358] Call Trace:
[40866.349363] ? kernfs_fop_open+0xc2/0x3b0
[40866.349366] kernfs_fop_open+0xc2/0x3b0
[40866.349368] ? kernfs_fop_read+0x1b0/0x1b0
[40866.349372] do_dentry_open+0x143/0x3a0
[40866.349373] vfs_open+0x2d/0x30
[40866.349376] do_last+0x194/0x900
[40866.349392] path_openat+0x8d/0x290
...
What do you mean by "reset"? Are you disconnecting the device from the
USB bus causing it to electronically be removed and then added back? Or
doing something else?
The microcontroller is doing a hard reset, which causes an electrical
USB reset, if I understand correctly. We have also occasionally seen
crashes on plug-in (and maybe unplug, though I have not seen that
personally).
... the traces seem _very_ short on the stuff on the web page,
can you send us the full traceback from the crash?
I have the kdump stuff, but I'm not sure how to give you a full
traceback. Do you want the whole contents of the /var/crash dirs?
That's not good, but might mean it is a filesystem issue, not a USB
issue.
Yes, possibly, though it might be an interaction between the filesystem
code and USB, since I'm seeing different traces. We have not seen these
crashes on some other motherboards, including some Intel laptop chipsets
and some AMD chipsets.
Ok, this trace:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1871143/comments/4
seems to point at the filesystem code. Are you sure you are creating
the image correctly?
If you unplug and plug the device back in with that same filesystem
image, does it work, or still crash?
Yes, it works fine. It might be something about the abruptness of the
disconnect and the speed with which it tries to reconnect. It is
intermittent, and doesn't always cause a crash.
We've been using these devices and their filesystems for years
successfully for several years. That doesn't mean the filesystem code
on-board is perfect, but we shouldn't be able to crash the kernel.
Thanks,
Dan
