Bug#810080: ghostscript: Infinite loop filling server logs with "File has unbalanced q/Q operators"
Package: ghostscript
Version: 9.06~dfsg-2+deb8u1
Severity: important
Dear Maintainer,
Short version:
* What led up to the situation?
"gs -o proper.pdf -sDEVICE=pdfwrite -dPDFSETTINGS=/prepress programmheft_2016.pdf" with http://www.naturpark-rheinland.de/programmheft_2016.pdf leads to infinite output of "**** File has unbalanced q/Q operators (too many Q's) ****" to stderr
* What exactly did you do (or not do) that was effective (or ineffective)?
A) Compiled upstream ghostscript 9.06 and executed the command above
B) Use the upstream ghostscript Resources directory instead of /usr/share/ghostscript/Resources
* What was the outcome of this action?
A) Worked without problems
B) Leads at least to an unrecoverable error instead
* What outcome did you expect instead?
Debians ghostscript package to work as upstream correctly rendering the PDF.
Long version:
One of our Debian wheezy webservers (ghostscript "9.05~dfsg-6.3+deb7u2") was brought down yesterday morning by running out of diskspace very quickly due to a spammed /var/log/apache2/error.log with 700GB of lines with
"**** File has unbalanced q/Q operators (too many Q's) ****".
It turned out this was due to a process trying to create a thumbnail image of a pdf file
"gs -q -dBATCH -dMaxBitmap=50000000 -dNOPAUSE -sDEVICE=pnmraw -dTextAlphaBits=4 -dGraphicsAlphaBits=4 -r72x72 -dFirstPage=1 -dLastPage=1 -sOutputFile=XXX -- YYY -c quit"
The issue is reproducible on a Debian jessie server (ghostscript "9.06~dfsg-2+deb8u1") too by simply executing
"gs -o proper.pdf -sDEVICE=pdfwrite -dPDFSETTINGS=/prepress programmheft_2016.pdf"
The file is available for download at http://www.naturpark-rheinland.de/programmheft_2016.pdf
All pdf viewers I tried had no problems displaying the file.
I asked for help at #ghostscript, you can find the log here: http://ghostscript.com/irclogs/2016/01/05.html
I compiled both gs905 and gs906 from ghostscripts git sources and could execute
"./gs -o proper.pdf -sDEVICE=pdfwrite -dPDFSETTINGS=/prepress programmheft_2016.pdf"
without errors.
Using the Resource folder of upstream ghostscript for the debian ghostscript package by executing
"gs -I../Resource/Init -o proper.pdf -sDEVICE=pdfwrite -dPDFSETTINGS=/prepress programmheft_2016.pdf"
leads to
Error: /rangecheck in --run--
Operand stack:
--dict:12/21(L)-- 1 11 3 --nostringval-- false 76666 DataSource --nostringval-- 0 16 --nostringval-- 12 --dict:2/2(L)--
Execution stack:
%interp_exit .runexec2 --nostringval-- --nostringval-- --nostringval-- 2 %stopped_push --nostringval-- --nostringval-- --nostringval-- false 1 %stopped_push 1910 1 3 %oparray_pop 1909 1 3 %oparray_pop 1893 1 3 %oparray_pop --nostringval-- --nostringval-- 2 1 1 --nostringval-- %for_pos_int_continue --nostringval-- --nostringval-- false 1 %stopped_push --nostringval-- --nostringval--
Dictionary stack:
--dict:1168/1684(ro)(G)-- --dict:1/20(G)-- --dict:83/200(L)-- --dict:83/200(L)-- --dict:109/127(ro)(G)-- --dict:293/300(ro)(G)-- --dict:25/31(L)-- --dict:6/8(L)-- --dict:25/40(L)-- --dict:1/1(ro)(G)-- --dict:14/15(L)-- --dict:1/1(ro)(G)-- --dict:4/5(L)-- --dict:1/1(ro)(G)-- --dict:7/15(L)-- --dict:9/20(L)--
Current allocation mode is local
GPL Ghostscript 9.06: Unrecoverable error, exit code 1
which is an unrecoverable error but at least no infinite spamming of the error log.
As a workaround I use this on our servers now:
git clone --single-branch --branch gs906 "http://git.ghostscript.com/ghostpdl.git"; ~/ghostpdl
mkdir /usr/local/share/ghostscript/
mv ~/ghostpdl/gs/Resource /usr/local/share/ghostscript/
rm -rf ~/ghostpdl
echo "GS_LIB=/usr/local/share/ghostscript/Resource/Init" >> /etc/environment
Since the problem does not exist on upstream ghostscript 9.05 or 9.06 but only in the debian package it must be due to differences between these too. This are the differences in Resource/Init/* http://pastebin.com/emSHcUFE
-- System Information:
Debian Release: 8.2
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 3.16.0-4-amd64 (SMP w/4 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages ghostscript depends on:
ii debconf [debconf-2.0] 1.5.56
ii gsfonts 1:8.11+urwcyr1.0.7~pre44-4.2
ii libc6 2.19-18+deb8u1
ii libgs9 9.06~dfsg-2+deb8u1
ghostscript recommends no packages.
Versions of packages ghostscript suggests:
pn ghostscript-x <none>
-- no debconf information
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