simple-scan seg faults if you unplug scanner and try to scan again

[Kit Westneat]

I'm running Ubuntu 10.10 and simple-scan 2.32.0 and I ran into a reproducible issue where if I scan something then unplug the scanner and try scanning again, the program segfaults. I got a core file, which I can put online somewhere if that would be useful. Here's the backtrace from the core:

Core was generated by `simple-scan'.
Program terminated with signal 11, Segmentation fault.
#0 0x00007fc8edc54212 in sanei_usb_open () from /usr/lib/sane/libsane-plustek.so.1
(gdb) bt
#0 0x00007fc8edc54212 in sanei_usb_open () from /usr/lib/sane/libsane-plustek.so.1
#1 0x00007fc8edc6593a in ?? () from /usr/lib/sane/libsane-plustek.so.1
#2 0x00007fc8edc6a974 in ?? () from /usr/lib/sane/libsane-plustek.so.1
#3 0x00007fc8edc6ba4e in sane_plustek_start () from /usr/lib/sane/libsane-plustek.so.1
#4 0x000000000041526a in ?? ()
#5 0x00007fc900bb17e4 in ?? () from /lib/libglib-2.0.so.0
#6 0x00007fc9029c5971 in start_thread () from /lib/libpthread.so.0
#7 0x00007fc90047f92d in clone () from /lib/libc.so.6
#8 0x0000000000000000 in ?? ()

Sometimes I have to hit the scan button many times to get it to crash, but it seems pretty consistent. Here's another backtrace, slightly different:

Program terminated with signal 11, Segmentation fault.
#0 0x00007f47e82fa7aa in vfprintf () from /lib/libc.so.6
(gdb) bt
#0 0x00007f47e82fa7aa in vfprintf () from /lib/libc.so.6
#1 0x00007f47e83aea80 in __vsnprintf_chk () from /lib/libc.so.6
#2 0x00007f47e83ae9ba in __snprintf_chk () from /lib/libc.so.6
#3 0x00007f47dcac7c90 in ?? () from /lib/libusb-0.1.so.4
#4 0x00007f47dcac7d6d in usb_os_open () from /lib/libusb-0.1.so.4
#5 0x00007f47dcac5af5 in usb_open () from /lib/libusb-0.1.so.4
#6 0x00007f47d96f41cf in sanei_usb_open () from /usr/lib/sane/libsane-plustek.so.1
#7 0x00007f47d970593a in ?? () from /usr/lib/sane/libsane-plustek.so.1
#8 0x00007f47d970a974 in ?? () from /usr/lib/sane/libsane-plustek.so.1
#9 0x00007f47d970ba4e in sane_plustek_start () from /usr/lib/sane/libsane-plustek.so.1
#10 0x000000000041526a in ?? ()
#11 0x00007f47e8ac97e4 in ?? () from /lib/libglib-2.0.so.0
#12 0x00007f47ea8dd971 in start_thread () from /lib/libpthread.so.0
#13 0x00007f47e839792d in clone () from /lib/libc.so.6
#14 0x0000000000000000 in ?? ()

So maybe another thread is modifying data that sanei_usb_open is working on? I managed to get a debug log, so I'll attach that as well.

Thanks,
Kit

[Robert Ancell (robert-ancell)]

The log shows it is the driver crashing. I am working on separating the driver code from the UI code so in the future these problems will not cause simple scan to crash.

[Michael Nagel (nailor)]

Robert is talking about Bug #564357
To get the crash fixed, your best bet is to get in contact with the sane-backend developers via http://www.sane-project.org/mailing-lists.html

I am closing this Bug Report, because we cannot do much about this in Simple Scan itself -- except for getting a process boundary between us and the driver, and that is what Bug #564357 is already about.

Best Regards
Michael