Re: Possible hungtask issue will be introduced with device_lock() in uevent_show()

[Greg KH]

On Tue, Dec 31, 2024 at 03:56:08PM +0800, Zhang Zekun wrote:
> Hi, Dan, Greg,
> 
> We have found a potential tungtask issue has been introduce by commit 9a71892cbcdb ("Revert "driver core: Fix uevent_show() vs driver detach race""), which revert the rcu in device_uevent but reintroduce the device_lock() in uevent_show(). The reproduce procedure is quite simple:

The revert just puts the original logic back in place, so this is not
anything new that has been introduced, right?  It's just that the
attempted fix didn't work, so a different fix needs to happen.

If you could help debug the original fix, that would be most appreciated
as none of us here are arguing that there isn't a bug present, only that
the fix caused different problems which required it to be reverted.

thanks,

greg k-h