RE: [PATCH][v2] Drivers: hv: Change flag to write log level in panic msg to false

[Michael Kelley]

From: Wei Liu <wei.liu@xxxxxxxxxx> Sent: Monday, July 6, 2020 3:56 AM
> 
> On Wed, Jul 01, 2020 at 07:33:25PM +0000, Sasha Levin wrote:
> > Hi
> >
> > [This is an automated email]
> >
> > This commit has been processed because it contains a -stable tag.
> > The stable tag indicates that it's relevant for the following trees: all
> >
> > The bot has tested the following trees: v5.7.6, v5.4.49, v4.19.130, v4.14.186, v4.9.228,
> v4.4.228.
> >
> > v5.7.6: Build OK!
> > v5.4.49: Failed to apply! Possible dependencies:
> >     53edce00ceb74 ("Drivers: hv: vmbus: Remove dependencies on guest page size")
> 
> Unrelated, shouldn't be backported.
> 
> >
> > v4.19.130: Failed to apply! Possible dependencies:
> >     53edce00ceb74 ("Drivers: hv: vmbus: Remove dependencies on guest page size")
> >
> 
> Unrelated, shouldn't be backported.
> 
> > v4.14.186: Failed to apply! Possible dependencies:
> >     4a5f3cde4d51c ("Drivers: hv: vmbus: Remove x86-isms from arch independent drivers")
> >     53edce00ceb74 ("Drivers: hv: vmbus: Remove dependencies on guest page size")
> >     7ed4325a44ea5 ("Drivers: hv: vmbus: Make panic reporting to be more useful")
> >     81b18bce48af3 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during
> panic")
> >     8afc06dd75c06 ("Drivers: hv: vmbus: Fix the issue with freeing up hv_ctl_table_hdr")
> >     ddcaf3ca4c3c8 ("Drivers: hv: vmus: Fix the check for return value from kmsg get dump
> buffer")
> >
> > v4.9.228: Failed to apply! Possible dependencies:
> >     4a5f3cde4d51c ("Drivers: hv: vmbus: Remove x86-isms from arch independent drivers")
> >     6ab42a66d2cc1 ("Drivers: hv: vmbus: Move Hypercall invocation code out of common
> code")
> >     73638cddaad86 ("Drivers: hv: vmbus: Move the check for hypercall page setup")
> >     76d36ab798204 ("hv: switch to cpuhp state machine for synic init/cleanup")
> >     81b18bce48af3 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during
> panic")
> >     8730046c1498e ("Drivers: hv vmbus: Move Hypercall page setup out of common code")
> >     d058fa7e98ff0 ("Drivers: hv: vmbus: Move the crash notification function")
> >
> > v4.4.228: Failed to apply! Possible dependencies:
> >     4a5f3cde4d51c ("Drivers: hv: vmbus: Remove x86-isms from arch independent drivers")
> >     619848bd07434 ("drivers:hv: Export a function that maps Linux CPU num onto Hyper-V
> proc num")
> >     6ab42a66d2cc1 ("Drivers: hv: vmbus: Move Hypercall invocation code out of common
> code")
> >     73638cddaad86 ("Drivers: hv: vmbus: Move the check for hypercall page setup")
> >     75ff3a8a9168d ("Drivers: hv: vmbus: avoid wait_for_completion() on crash")
> >     76d36ab798204 ("hv: switch to cpuhp state machine for synic init/cleanup")
> >     81b18bce48af3 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during
> panic")
> >     8730046c1498e ("Drivers: hv vmbus: Move Hypercall page setup out of common code")
> >     a108393dbf764 ("drivers:hv: Export the API to invoke a hypercall on Hyper-V")
> >     d058fa7e98ff0 ("Drivers: hv: vmbus: Move the crash notification function")
> 
> Just from reading the subject lines it seems to me a lot of the possible
> dependencies aren't really related to this patch functionally. It could
> be that they are touching the same area of code which create some
> contextual dependencies. Some of the listed dependencies should
> definitively _not_ be backported.
> 
> Michael and Joseph, how far do you want this to be backported? It may be
> easier for us to provide bespoke versions of this patch to the stable
> trees we care about?
> 

The code being changed was added in 4.19, so that's the earliest kernel version
to which it makes sense to backport.  53edce00ceb74 is an unrelated change
to the same line of code (changes PAGE_SIZE to HV_HYP_PAGE_SIZE), so a bespoke
version of this patch is needed for the stable trees.  All-in-all, this patch is a modest
optimization, so backporting is nice but not required.

Michael