Bug#852082: gwc in testing crashes at startup

[James Cowgill]

Control: severity -1 grave

Hi,

[Jaromír: please send mail to the bug, not the list]

On 21/01/17 14:18, Christian Grigis wrote:
> Package: gwc
> Version: 0.21.19~dfsg0-6
> Severity: important
> 
> Running 'gnome_wave_cleaner' from the testing package version
> (0.21.19~dfsg0-6) crashes immediately at startup:
> 
> $ gnome_wave_cleaner 
> Current stack limit: 8388608 bytes
> Segmentation fault

This bug is clearly RC. Jaromír, you did test this before uploading it
right?

[...]
> The gdb backtrace gives:
> 
> (gdb) run
> Starting program: /home/glove/tmp/gwc-testing/gwc-0.21.19~dfsg0/gwc 
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
> Current stack limit: 8388608 bytes
> 
> Program received signal SIGSEGV, Segmentation fault.
> 0x00007ffff6e047f9 in g_type_is_a () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
> (gdb) bt
> #0  0x00007ffff6e047f9 in g_type_is_a () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
> #1  0x00007ffff7519084 in gtk_type_new () from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
> #2  0x000055555557223c in led_bar_new (segments=20, orientation=0) at gtkledbar.c:82

The problem is here. led_bar_get_type returns an unsigned int, but
gtk_type_new expects a "GtkType" which is an integer with the same size
as a pointer. This code is going to need porting to work on 64-bit arches.

> I experimented with optimization levels but even -O0 gives the crash.
> 
> However, it looks like it is related to the compiler, because forcing to
> compile with gcc-5 instead of gcc-6 produces a binary that starts up
> normally.

This is probably related to PIE being enabled. I suspect that without
PIE (and therefore ASLR), by chance all the pointers were < 4GB so the
bug never occurred.

James

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