SEGFAULT when reinitializing a scanner

[Dmitry]

I have Canon Lide 220. I have libsane from Xenial (1.0.25) compiled with debuild. If I initialize the scanner with sane_open(), then immediately de-initialize it with sane_close(), and then sane_open() again, sane_start() will crash after that. The crash happens in genesys_low.c/sanei_genesys_generate_gamma_buffer() line #1240:

value=dev->sensor.gamma_table[GENESYS_RED][i];

The issue is that if I reinitialize the scanner, its gamma table is lost (dev->sensor.gamma_table). After reinitializing sane_start() tries to use non-initialized gamma table and crashes. Possible WORKAROUND, NOT A FIX:

In genesys_low.c/sanei_genesys_asic_init() line #1378 find and comment out the following code:

   if (dev->already_initialized && !cold)
    {
      DBG (DBG_info, "%s: already initialized, nothing to do\n", __FUNCTION__);
      return SANE_STATUS_GOOD;
    }

So it becomes

 /* if (dev->already_initialized && !cold)
    {
      DBG (DBG_info, "%s: already initialized, nothing to do\n", __FUNCTION__);
      return SANE_STATUS_GOOD;
    }
*/

After this ugly hack sane will reinitialize the gamma table every time, and the application will not crash. Sample C++ app is attached. Simply compile and run with Lide 220 connected.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: libsane 1.0.25+git20150528-1ubuntu2
ProcVersionSignature: Ubuntu 3.13.0-66.108-generic 3.13.11-ckt27
Uname: Linux 3.13.0-66-generic i686
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: i386
CurrentDesktop: KDE
Date: Tue Mar 15 17:36:02 2016
InstallationDate: Installed on 2015-10-24 (144 days ago)
InstallationMedia: Kubuntu 14.04.3 LTS "Trusty Tahr" - Beta i386 (20150805)
SourcePackage: sane-backends
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[penalvch (penalvch)]

Dmitry, thank you for reporting this and helping make Ubuntu better.

To see if this is already resolved in Ubuntu, could you please test http://cdimage.ubuntu.com/daily-live/current/ and advise to the results?

[Launchpad Janitor (janitor)]

[Expired for sane-backends (Ubuntu) because there has been no activity for 60 days.]