APPLIED: [Xenial][PATCH 0/1] Fix for libmbim-proxy using 100% CPU

[Khaled Elmously]

On 2019-11-05 17:41:08 , Wen-chien Jesse Sung wrote:
> BugLink: https://launchpad.net/bugs/1851347
> 
> == Impact ==
> A Dell Edge Gateway 3002 user reported that `top` reports around
> 100% CPU usage for the libmbim-proxy process. Seen in at least
> 40% of their devices at some point during the last 6 months.
> The CPU keeps high at ~100% days or weeks, but does return back
> to normal without a reboot. The LTE connectivity is seemingly
> still working as usual.
> 
> The issue starts after an EPIPE error in the syslogs:
> cdc_mbim 1-3:1.12: nonzero urb status received: -EPIPE
> 
> == Fix ==
> 8fec9355a968 USB: cdc-wdm: ignore -EPIPE from GetEncapsulatedResponse
> This has been in mainline kernel since 4.14.
> 
> == Testcase ==
> Connect to the LTE network and see if libmbim-proxy uses 100% after
> some point.
> 
> == Risk of Regression ==
> Low, since
> 1. Already tested by original reporter and no issue found after
>    more than a week (usually it fails twice in a week).
> 2. Ignoring -EPIPE is the default behavior after 4.14.
> 
> 
> Bjørn Mork (1):
>   USB: cdc-wdm: ignore -EPIPE from GetEncapsulatedResponse
> 
>  drivers/usb/class/cdc-wdm.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> -- 
> 2.20.1
> 
> 
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