#293 Segmentation fault when trying to open a djvu file with djview4

[Denis Karpovskii]

Hi.
When I try to open any file with djview4, it crashes with a segmentation fault.
Attached a full backtrace.
I tried then to compile djvulibre and djview4 from sources and launch using the freshly created binaries, but it still crashes.
What I did:

# cd in djvulibre and djview sources
./configure --prefix=/usr/local
make -j4
sudo make install

# then launch djview using the freshly compiled version of the library
cd /usr/local/bin
LD_LIBRARY_PATH=/usr/local/lib ./djview ~/path/to/djvu/file
# segmentation fault

Affected files: Every file I tried to open from Djvu site

OS: KDE neon 18.04 (based on ubuntu 18.04).

[Janusz]

No problem here with

Package: djview4
Version: 4.10.6-6

Debian Release: buster/sid

Regards

Janusz

On Sun, Oct 07 2018 at 8:17 GMT, Denis Karpovskii wrote:

---

[bugs:#293] Segmentation fault when trying to open a djvu file with djview4

Status: open
Group: djvulibre
Created: Sun Oct 07, 2018 08:17 AM UTC by Denis Karpovskii
Last Updated: Sun Oct 07, 2018 08:17 AM UTC
Owner: nobody
Attachments:

• gdb_log.txt (13.1 kB; text/plain)

Hi.
When I try to open any file with djview4, it crashes with a segmentation fault.
Attached a full backtrace.
I tried then to compile djvulibre and djview4 from sources and launch using the freshly created binaries, but it still
crashes.
What I did:

cd in djvulibre and djview sources

./configure --prefix=/usr/local
make -j4
sudo make install

then launch djview using the freshly compiled version of the library

cd /usr/local/bin
LD_LIBRARY_PATH=/usr/local/lib ./djview ~/path/to/djvu/file

segmentation fault

Affected files: Every file I tried to open from Djvu site

OS: KDE neon 18.04 (based on ubuntu 18.04).

---

Sent from sourceforge.net because you indicated interest in https://sourceforge.net/p/djvu/bugs/293/

To unsubscribe from further messages, please visit https://sourceforge.net/auth/subscriptions/

--
,
Janusz S. Bien
emeryt (emeritus)
https://sites.google.com/view/jsbien

[Leon Bottou]

Denis: what kind of processor is found in your computer? Exact model..

Also, does the crash subsists if you set the environment variable
$ exportLIBDJVU_DISABLE_MMX=1.

[Denis Karpovskii]

Denis: what kind of processor is found in your computer? Exact model..

Intel Pentium Silver N5000

Also, does the crash subsists if you set the environment variable

No. With that variable set to 1 everything works perfect.

[Leon Bottou]

On Sunday, October 7, 2018 6:15:41 PM EDT Denis Karpovskii wrote:

Intel Pentium Silver N5000

I just pushed a change in djvulibre-3.5 git that eliminates a test that was inherited from ancient processors and relies on the equally ancient SMSW instruction.
The diff is at https://sourceforge.net/p/djvu/djvulibre-git/ci/8407dd3421f720ab2e1a61e3f1e60e08967f98db/

The old code was known to work on a lot of intel64 processors, but yours may be different.
Maybe this solves your problem.

• Leon

[Denis Karpovskii]

Yeah, it works now. Thank you.

[Leon Bottou]

Fixed. Thanks.

Your processor, the Pentium Silver N5000 is based on a Goldmond core which is a kind of Atom instead of a mainstream Intel x86 processor. Clearly there are differences in the obscure parts of the instruction set (I suspect the SMSW instruction).

[Leon Bottou]

More information at
https://lwn.net/Articles/738209/

Apparently the linux kernel now sets bit CR4.UMIP which causes a GP fault when SMSW is executed. The kernel is supposed to catch the trap and return a dummy value. Why this fails to happen on your system is unknown....