Re: [PATCH 5.10 147/243] NFSD: Fix TP_printk() format specifier in nfsd_clid_class

[Sasha Levin]

On Wed, Jul 21, 2021 at 10:04:13AM -0400, Steven Rostedt wrote:
> On Tue, 20 Jul 2021 23:48:47 +0200
> Pavel Machek <pavel@xxxxxxx> wrote:
>
> > Hi!
> >
> > > [ Upstream commit a948b1142cae66785521a389cab2cce74069b547 ]
> > >
> > > Since commit 9a6944fee68e ("tracing: Add a verifier to check string
> > > pointers for trace events"), which was merged in v5.13-rc1,
> > > TP_printk() no longer tacitly supports the "%.*s" format specifier.
> > >
> > > These are low value tracepoints, so just remove them.
> >
> > So I understand we want this for mainline, but AFAICT 5.10 does not
> > have 9a6944fee68e ("tracing: Add a verifier to check string pointers
> > for trace events") commit, so this does not fix any bug and removal of
> > tracepoints can be surprising.
>
> Thanks for pointing this out. I get so many stable patches, I don't
> have time to look at all of them.
>
> Greg, I don't think this should be backported. The verifier code had a
> bug in it that broke the '%.*s' formats. This patch removed the good
> code because of the broken code.
>
> See eb01f5353bdaa ("tracing: Handle %.*s in trace_check_vprintf()")

Uh, yes, I'll drop it. Thanks for catching this!

--
Thanks,
Sasha