The full backtrace shows:
(gdb) backtrace full
#0 0x0000000000428d80 in read_callback (s=0xced1b0, length=4,
userdata=0x92d600) at mainwindow.cc:385
w = 0x92d600
data = 0x0
v = 7.1675486625997992e-317
__PRETTY_FUNCTION__ = "void read_callback(pa_stream*,
size_t, void*)"
#1 0x00007ffff3adad8b in ?? ()
from /usr/lib/x86_64-linux-gnu/libpulse.so.0
No symbol table info available.
#2 0x00007fffee0bb46d in ?? ()
from /usr/lib/x86_64-linux-gnu/pulseaudio/libpulsecommon-4.0.so
No symbol table info available.
#3 0x00007ffff3d17b77 in ?? ()
from /usr/lib/x86_64-linux-gnu/libpulse-mainloop-glib.so.0
No symbol table info available.
#4 0x00007ffff3f63526 in g_main_context_dispatch ()
from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#5 0x00007ffff3f63878 in ?? ()
from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#6 0x00007ffff3f63b3a in g_main_loop_run ()
from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#7 0x00007ffff59a444d in gtk_main ()
from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
No symbol table info available.
#8 0x00007ffff7a1a8f1 in Gtk::Main::run(Gtk::Window&) ()
from /usr/lib/x86_64-linux-gnu/libgtkmm-3.0.so.1
No symbol table info available.
#9 0x0000000000438981 in main (argc=1, argv=0x7fffffffdb28) at
pavucontrol.cc:670
kit = <incomplete type>
mainWindow = 0x92d600
m = 0x8ee130
options = <incomplete type>
group = <incomplete type>
entry = <incomplete type>
__PRETTY_FUNCTION__ = "int main(int, char**)"
So indeed data is NULL.
--
John
On Sun, 2014-02-23 at 04:52 +0100, Vincent Lefevre wrote:
> On 2014-02-22 18:58:08 -0500, John M. wrote:
> > Program received signal SIGSEGV, Segmentation fault.
> > 0x0000000000428d80 in read_callback (s=0xcea800, length=4,
> > userdata=0x9561b0) at mainwindow.cc:385
> > 385 v = ((const float*) data)[length / sizeof(float) -1];
> [...]
>
> Thanks. The src/mainwindow.cc file contains:
>
> if (pa_stream_peek(s, &data, &length) < 0) {
> show_error(_("Failed to read data from stream"));
> return;
> }
>
> assert(length > 0);
> assert(length % sizeof(float) == 0);
>
> v = ((const float*) data)[length / sizeof(float) -1];
>
> And according to the pa_stream_peek documentation
>
>
> http://freedesktop.org/software/pulseaudio/doxygen/stream_8h.html#ac2838c449cde56e169224d7fe3d00824
>
> "If there is no data at the current read index, it means that either
> the buffer is empty or it contains a hole (that is, the write index
> is ahead of the read index but there's no data where the read index
> points at). If the buffer is empty, data will be NULL and nbytes will
> be 0. If there is a hole, data will be NULL and nbytes will contain
> the length of the hole."
>
> data can be NULL and the code is obviously buggy.
>
Starting program: /usr/bin/pavucontrol
warning: no loadable sections found in added symbol-file system-supplied DSO at
0x7ffff7ffa000
warning: Could not load shared library symbols for linux-vdso.so.1.
Do you need "set solib-search-path" or "set sysroot"?
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7fffe874a700 (LWP 31513)]
Program received signal SIGSEGV, Segmentation fault.
0x0000000000428d80 in read_callback (s=0xceda40, length=4, userdata=0x956200)
at mainwindow.cc:385
385 v = ((const float*) data)[length / sizeof(float) -1];
#0 0x0000000000428d80 in read_callback (s=0xceda40, length=4,
userdata=0x956200) at mainwindow.cc:385
w = 0x956200
data = 0x0
v = 6.9063816096829495e-317
__PRETTY_FUNCTION__ = "void read_callback(pa_stream*, size_t, void*)"
#1 0x00007ffff3adad8b in ?? () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
No symbol table info available.
#2 0x00007fffee0bb46d in ?? () from
/usr/lib/x86_64-linux-gnu/pulseaudio/libpulsecommon-4.0.so
No symbol table info available.
#3 0x00007ffff3d17b77 in ?? () from
/usr/lib/x86_64-linux-gnu/libpulse-mainloop-glib.so.0
No symbol table info available.
#4 0x00007ffff3f63526 in g_main_context_dispatch () from
/lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#5 0x00007ffff3f63878 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#6 0x00007ffff3f63b3a in g_main_loop_run () from
/lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#7 0x00007ffff59a444d in gtk_main () from
/usr/lib/x86_64-linux-gnu/libgtk-3.so.0
No symbol table info available.
#8 0x00007ffff7a1a8f1 in Gtk::Main::run(Gtk::Window&) () from
/usr/lib/x86_64-linux-gnu/libgtkmm-3.0.so.1
No symbol table info available.
#9 0x0000000000438981 in main (argc=1, argv=0x7fffffffdb28) at
pavucontrol.cc:670
kit = <incomplete type>
mainWindow = 0x956200
m = 0x937230
options = <incomplete type>
group = <incomplete type>
entry = <incomplete type>
__PRETTY_FUNCTION__ = "int main(int, char**)"
Kill the program being debugged? (y or n) Please answer y or n.
Kill the program being debugged? (y or n)
