Bug#1050592: perl: F_GETLK / F_GETLK64 confusion on ppc64el breaking libfile-fcntllock-perl

[Niko Tyni]

(full quote for the benefit of the Aurelien and other glibc maintainers)

On Sat, Aug 26, 2023 at 09:07:38PM +0300, Niko Tyni wrote:
> Package: perl
> Version: 5.36.0-8
> Severity: serious
> X-Debbugs-Cc: debian-powerpc at lists.debian.org
> Control: affects -1 libfile-fcntllock-perl
> 
> Hi,
> 
> debugging an unexpected autopkgtest failure of
> libfile-fcntllock-perl_0.22-4+b1 with perl_5.36.0-8 on ppc64el [1] I found
> it's because the old perl binary (5.36.0-7) was built with the fcntl(2)
> constant F_GETLK == 12, but the new one with F_GETLK == 5 [2].
> 
> There are no source or build system changes in perl that would have caused
> this change. The failure is currently blocking perl testing migration,
> so filing at 'serious'.
> 
> Perl is built with -D_FILE_OFFSET_BITS=64, and I see that on bullseye
> this causes F_GETLK == F_GETLK64 == 12, but on bookworm and later
> F_GETLK == 5 while F_GETLK64 == 12 [3]. I didn't find the exact
> change that caused this yet.
> 
> As can be expected from the above, building libfile-fcntllock-perl on
> bookworm against perl_5.36.0-7 makes it fail its test suite in a similar
> way. And rebuilding it on sid against perl_5.36.0-8 makes it pass.
> 
> On amd64 the constants have stayed equal (== 5) from bullseye to sid,
> and _FILE_OFFSET_BITS=64 doesn't affect them. What's the deal on ppc64el?
> 
> Copying the powerpc porters list. Could you please look into this?
> 
> [1] https://ci.debian.net/data/autopkgtest/unstable/ppc64el/libf/libfile-fcntllock-perl/34669085/log.gz
> [2] perl -MPOSIX -E 'say F_GETLK'
> [3] printf '#include <fcntl.h>\nF_GETLK\nF_GETLK64\n' | cpp -D_FILE_OFFSET_BITS=64 | tail -2

I think the relevant change here is this in libc6-dev_2.36-9+deb12u1 for bookworm:

--- libc6-dev_2.36-9/usr/include/powerpc64le-linux-gnu/bits/fcntl.h     2023-04-10 09:35:16.000000000 +0100
+++ libc6-dev_2.36-9+deb12u1/usr/include/powerpc64le-linux-gnu/bits/fcntl.h     2023-07-13 19:07:47.000000000 +0100
@@ -33,6 +33,12 @@
 # define __O_LARGEFILE 0200000
 #endif
 
+#if __WORDSIZE == 64
+# define F_GETLK       5
+# define F_SETLK       6
+# define F_SETLKW      7
+#endif
+

and a similar one in 2.37-2 for trixie/sid.

The applicable changelog entry is presumably

   [ Aurelien Jarno ]
   * debian/patches/git-updates.diff: update from upstream stable branch:
     [...]
     - Not affecting bookworm release architectures:
       - Fix LFS POSIX lock constants for powerpc64.

Aurelien, it seems that there's an oversight as ppc64el is a release architecture?

I can see that this changed for the better, but what should I do with the above
breakage? Rebuild perl and libfcntl-fcntllock-perl and declare some Breaks?
Do we want to do that for stable too?
-- 
Niko Tyni   ntyni at debian.org