Re: [PATCH 2/4] fs/resctrl: Free mon_data structures on rdt_get_tree() failure

[Chen, Yu C]

On 5/11/2026 11:15 AM, Luck, Tony wrote:
> On Sat, May 09, 2026 at 08:43:36PM +0800, Chen, Yu C wrote:
> > On 5/9/2026 5:36 AM, Luck, Tony wrote:
> > > On Fri, May 08, 2026 at 11:21:41AM -0700, Tony Luck wrote:
> > >
> > >   From 0263035539f805f5d4bddcef8968b551354cb86d Mon Sep 17 00:00:00 2001
> > > From: Tony Luck <tony.luck@xxxxxxxxx>
> > > Date: Thu, 7 May 2026 13:48:51 -0700
> > > Subject: [PATCH] fs/resctrl: Free mon_data structures on rdt_get_tree()
> > >    failure
> > >
> > > If mkdir_mondata_all() succeeds but a subsequent call in rdt_get_tree()
> > > fails, the mon_data structures allocated by mon_get_kn_priv() are
> > > leaked. Add mon_put_kn_priv() to the out_mongrp error path to free
> > > them.
> > >
> > > Fixes: ee4f0ec938ad ("fs/resctrl: Simplify allocation of mon_data structures")
> >
> > I did not find above commit in vanilla kernel, should it be 2a6566038544
> > ("x86/resctrl:
> > Expand the width of domid by replacing mon_data_bits") where
> > mon_put_kn_priv() was introduced?
>
> Thanks for the catch. Another strike against Claude. It didn't hallucinate
> this commit for the fixes tag, that commit does appear in my local repo.
> But in a dead-end branch I created to write the patch. I posted it here
> in v3 of my telemetry series:
>
> https://lore.kernel.org/all/20250407234032.241215-2-tony.luck@xxxxxxxxx/
>
> But James Morse picked it up in v11 of his "Move resctrl filessytem code
> to fs/resctrl" series:
>
> https://lore.kernel.org/all/20250513171547.15194-13-james.morse@xxxxxxx/
>
> where it was applied upstream in the 2a6566038544 commit you found.
>
> I'm somewhat confused that Claude dug through my other branches instead
> of just looking for ancestors of the current branch. Maybe I need an
> explicit instruction to AI agents on how to find commits to use for
> Fixes: tags?

I guess so, Opus 4.6 suggested the following prompt:
"When generating Fixes: tags, only consider commits reachable from the
current branch (git log). Do not search other local branches."

thanks,
Chenyu

> Claude is now double-fired.
>
> -Tony