tag 750226 patch thanks On Mon, Jun 02, 2014 at 07:20:18PM +0200, gregor herrmann wrote: > Package: libcache-mmap-perl > Version: 0.11-2 > Severity: important > Tags: jessie sid upstream > User: debian-p...@lists.debian.org > Usertags: perl-5.20-transition > Forwarded: https://rt.cpan.org/Public/Bug/Display.html?id=95940
> libcache-mmap-perl fails to build with perl 5.20. The attached patch fixes this for me on both 5.18 and 5.20. -- Niko Tyni nt...@debian.org
>From 610a7fd5092921cc317d77eedf626b2c62ca4a38 Mon Sep 17 00:00:00 2001 From: Niko Tyni <nt...@debian.org> Date: Mon, 28 Jul 2014 00:15:11 +0300 Subject: [PATCH] Avoid Copy-On-Write problems with Perl 5.20 Quoting Dave Mitchell in https://rt.cpan.org/Public/Bug/Display.html?id=95940 After FC's commit, $buf gets marked as COW, since its a copy of a COWable constant (the constant string "") and mmap() never unsets this flag before stealing its buffer. So later on when it applies substr() to $buf, the var is assumed to be COW and bad things happen to it. The correct usage is still up for debate (see Leon's use case in rt.perl.org tickets #116407 and #116925), but calling SvPV_force() first would be a good first step (although that will cause the previous contents of PVX() to leak). It might be better for Mmap.pm to call mmap() with an undef value rather than assigning "" to it first. Bug: https://rt.cpan.org/Public/Bug/Display.html?id=95940 Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=750226 --- Mmap.pm | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Mmap.pm b/Mmap.pm index c3501b1..21925e9 100644 --- a/Mmap.pm +++ b/Mmap.pm @@ -823,7 +823,7 @@ sub _set_options{ # mmap() isn't supposed to work on locked files, so unlock $self->_unlock; - mmap($self->{_mmap}='',$size,$self->{_fh}) + mmap($self->{_mmap}=undef,$size,$self->{_fh}) or do{ delete $self->{_mmap}; croak "Can't mmap $self->{_filename}: $!"; -- 2.0.1
