APPLIED[Unstable]: [SRU] [F/G/Unstable/OEM-5.6/OEM-5.10] [PATCH 0/1] Fix reading speed and duplex sysfs on igc device

[Seth Forshee]

On Sat, Dec 05, 2020 at 12:10:02AM +0800, Kai-Heng Feng wrote:
> BugLink: https://bugs.launchpad.net/bugs/1906851
> 
> [Impact]
> Reading speed and duplex sysfs on igc device when it's runtime suspended
> will make it stops working. Even kernel panic sometimes.
> 
> [Fix]
> If igc device is runtime suspended, it means link isn't up, so we can
> just report speed as -1 and duplex as unknown.
> 
> [Test]
> $ cat /sys/class/net/*/speed
> Then we'll see:
> [  123.449883] igc 0000:03:00.0 enp3s0: PCIe link lost, device now detached
> [  123.450052] BUG: kernel NULL pointer dereference, address: 0000000000000008
> 
> With the fix applied,
> $ cat /sys/class/net/*/speed
> -1
> 
> [Where problems could occur]
> Not at all. Reading register when device is runtime suspended is just
> wrong. The fix prevents it from happening.

Applied to unstable/master, thanks!