[Pkg-gmagick-im-team] Bug#834163: libmagick++: undefined behavior on concurrent access because mutex locking is poorly done

[Guillaume Gimenez]

Package: libmagick++-6.q16-5v5
Version: 8:6.8.9.9-7.2
Severity: important
File: libmagick++
Tags: patch

Dear Maintainer,

There is a bug in the locking implentation (RAII was the intended C++ idiom) that has been fixed upstream.

http://git.imagemagick.org/repos/ImageMagick/commit/5cbe21ed2728da0e611154d2f8e41bb63095a62c

Unfortunately, the commit message is empty...

In the unfixed code, the mutex acquisition has no effect and doesn't prevent concurrent access to ref counters.

This bug generates a lot of crashes when Magick++ is used with multi-threaded applications


-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.6.0-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=UTF-8 (charmap=locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
ANSI_X3.4-1968)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages libmagick++-6.q16-5v5:amd64 depends on:
ii  libc6                  2.23-4
ii  libgcc1                1:6.1.1-10
ii  libmagickcore-6.q16-2  8:6.8.9.9-7.2
ii  libmagickwand-6.q16-2  8:6.8.9.9-7.2
ii  libstdc++6             6.1.1-10

libmagick++-6.q16-5v5:amd64 recommends no packages.

libmagick++-6.q16-5v5:amd64 suggests no packages.