Re: [stable 4.4, 4.9, 4.14, 4.19 LTS] Missing fix "memcg: fix a crash in wb_workfn when a device disappears"

[Greg KH]

On Wed, Feb 10, 2021 at 11:04:19AM -0500, Mathieu Desnoyers wrote:
> Hi,
> 
> While reconciling the lttng-modules writeback instrumentation with its counterpart
> within the upstream Linux kernel, I notice that the following commit introduced in
> 5.6 is present in stable branches 5.4 and 5.5, but is missing from LTS stable branches
> for 4.4, 4.9, 4.14, 4.19:
> 
> commit 68f23b89067fdf187763e75a56087550624fdbee
> ("memcg: fix a crash in wb_workfn when a device disappears")
> 
> Considering that this fix was CC'd to the stable mailing list, is there any
> reason why it has not been integrated into those LTS branches ?

Yes, it doesn't apply at all.  If you think this is needed, I will
gladly take backported and tested patches.

But why do you think this is needed in older kernels?  Have you hit
this in real-life?

thanks,

greg k-h