Red Hat Bugzilla – Bug 1302121
"convert" command hangs when converting pdf to png
Last modified: 2016-11-04 04:28:44 EDT
Created attachment 1118609 [details] test.pdf in question Description of problem: When converting a PDF to PNG using 'convert', it hangs. Version-Release number of selected component (if applicable): RHEL 7 ImageMagick-6.7.8.9-10.el7.x86_64 How reproducible: Always Steps to Reproduce: 1. Download PDF 2. Attempt to convert PDF with 'convert test.pdf test.png' Actual results: Hangs, no output Expected results: Output test.png Additional info: Customer was able to get around this using an upstream version.
The pstack shows that the convert command is actually waiting for the 'gs' command to return. So this is most likely a problem in ghostscript and not ImageMagick. I'm moving the components and I'll see if I can determine what gs is up to to cause the problem.
affected, too
According to strace, ImageMagick is executing the following command: /usr/bin/gs -q -dQUIET -dSAFER -dBATCH -dNOPAUSE -dNOPROMPT \ -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=2 -sDEVICE=pam \ -dTextAlphaBits=4 -dGraphicsAlphaBits=4 -r72x72 -dUseCIEColor \ -sOutputFile=/tmp/magick-gvr4A3Qr-%08d -f/tmp/magick-FGoe7KZa \ -f/tmp/magick-B-PH4C8T" /tmp/magick-B-PH4C8T is a symlink to the original file passed to ImageMagick /tmp/magick-FGoe7KZa is a file containing one space (0x20): $ hexdump -C /tmp/magick-FGoe7KZa 00000000 20 | | This works (or at least it returns): $ gs -dSAFER -dBATCH -dNOPAUSE -dNOPROMPT -sDEVICE=pam \ -sOutputFile=test.pam -f test.pdf GPL Ghostscript 9.07 (2013-02-14) Copyright (C) 2012 Artifex Software, Inc. All rights reserved. This software comes with NO WARRANTY: see the file PUBLIC for details. Processing pages 1 through 1. Page 1 Adding options fails when I reach "-dTextAlphaBits=4": /usr/bin/gs -dSAFER -dBATCH -dNOPAUSE -dNOPROMPT \ -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=2 -sDEVICE=pam \ -dTextAlphaBits=4 -sOutputFile=test.pam -f test.pdf The rest of the command, without "-dTextAlphaBits=4" doesn't hang: $ /usr/bin/gs -dSAFER -dBATCH -dNOPAUSE -dNOPROMPT \ -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=2 -sDEVICE=pam \ -dGraphicsAlphaBits=4 -r72x72 -dUseCIEColor -sOutputFile=test.pam \ -f test.pdf GPL Ghostscript 9.07 (2013-02-14) Copyright (C) 2012 Artifex Software, Inc. All rights reserved. This software comes with NO WARRANTY: see the file PUBLIC for details. Processing pages 1 through 1. Page 1 So I'm guessing the problem is with "-dTextAlphaBits=4"
Upstream commit that fixes this issue as side-effect of it: http://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff;h=c27113ab96a8010b596
*** Bug 1268259 has been marked as a duplicate of this bug. ***
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHBA-2016-2550.html