Re: FAILED: patch "[PATCH] scripts/tags.sh: fix incompatibility with PCRE2" failed to apply to 5.10-stable tree

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Feb 28, 2023 at 08:22:01PM +0000, Carlos Llamas wrote:
> On Tue, Feb 28, 2023 at 07:49:37PM +0100, gregkh@linuxfoundation.org wrote:
> > 
> > The patch below does not apply to the 5.10-stable tree.
> > If someone wants it applied there, or to any other stable or longterm
> > tree, then please email the backport, including the original git commit
> > id to <stable@vger.kernel.org>.
> > 
> > Possible dependencies:
> > 
> > 6ec363fc6142 ("scripts/tags.sh: fix incompatibility with PCRE2")
> > 7394d2ebb651 ("scripts/tags.sh: Invoke 'realpath' via 'xargs'")
> > 
> > thanks,
> > 
> > greg k-h
> > 
> > ------------------ original commit in Linus's tree ------------------
> > 
> > From 6ec363fc6142226b9ab5a6528f65333d729d2b6b Mon Sep 17 00:00:00 2001
> > From: Carlos Llamas <cmllamas@google.com>
> > Date: Wed, 15 Feb 2023 18:38:50 +0000
> > Subject: [PATCH] scripts/tags.sh: fix incompatibility with PCRE2
> > 
> > Starting with release 10.38 PCRE2 drops default support for using \K in
> > lookaround patterns as described in [1]. Unfortunately, scripts/tags.sh
> > relies on such functionality to collect all_compiled_soures() leading to
> > the following error:
> > 
> >   $ make COMPILED_SOURCE=1 tags
> >     GEN     tags
> >   grep: \K is not allowed in lookarounds (but see PCRE2_EXTRA_ALLOW_LOOKAROUND_BSK)
> > 
> > The usage of \K for this pattern was introduced in commit 4f491bb6ea2a
> > ("scripts/tags.sh: collect compiled source precisely") which speeds up
> > the generation of tags significantly.
> > 
> > In order to fix this issue without compromising the performance we can
> > switch over to an equivalent sed expression. The same matching pattern
> > is preserved here except \K is replaced with a backreference \1.
> > 
> > [1] https://www.pcre.org/current/doc/html/pcre2syntax.html#SEC11
> > 
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Cc: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
> > Cc: Masahiro Yamada <masahiroy@kernel.org>
> > Cc: Jialu Xu <xujialu@vimux.org>
> > Cc: Vipin Sharma <vipinsh@google.com>
> > Cc: stable@vger.kernel.org
> > Fixes: 4f491bb6ea2a ("scripts/tags.sh: collect compiled source precisely")
> > Signed-off-by: Carlos Llamas <cmllamas@google.com>
> > Link: https://lore.kernel.org/r/20230215183850.3353198-1-cmllamas@google.com
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > 
> > diff --git a/scripts/tags.sh b/scripts/tags.sh
> > index 1ad45f17179a..6b9001853890 100755
> > --- a/scripts/tags.sh
> > +++ b/scripts/tags.sh
> > @@ -98,7 +98,7 @@ all_compiled_sources()
> >  	{
> >  		echo include/generated/autoconf.h
> >  		find $ignore -name "*.cmd" -exec \
> > -			grep -Poh '(?(?=^source_.* \K).*|(?=^  \K\S).*(?= \\))' {} \+ |
> > +			sed -n -E 's/^source_.* (.*)/\1/p; s/^  (\S.*) \\/\1/p' {} \+ |
> >  		awk '!a[$0]++'
> >  	} | xargs realpath -esq $([ -z "$KBUILD_ABS_SRCTREE" ] && echo --relative-to=.) |
> >  	sort -u
> > 
> 
> Hi Greg,
> 
> This patch would be needed in 5.10+ branches. Instead of backporting it,
> I think is better to pick the "xargs" fix too. So can you please take
> the following two commits for 5.10 and 5.15? I've verified they both
> apply and work as expected with new PCRE2.
> 
> 7394d2ebb651 ("scripts/tags.sh: Invoke 'realpath' via 'xargs'")
> 6ec363fc6142 ("scripts/tags.sh: fix incompatibility with PCRE2")

Good idea, now queued up, thanks!

greg k-h