Re: pkg/55899 graphics/cheese build locks up by gst-inspect

[Michael van Elst <mlelstv%serpens.de@localhost>]

The following reply was made to PR pkg/55899; it has been noted by GNATS.

From: Michael van Elst <mlelstv%serpens.de@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: pkg/55899 graphics/cheese build locks up by gst-inspect
Date: Wed, 10 Mar 2021 09:38:32 +0100

 The gst-plugin-scann helper program crashes with a BUS error.
 
 8621      1 gst-plugin-scann PSIG  SIGBUS SIG_DFL: code=BUS_ADRALN, addr=0xf2d606a1, trap=-1845493727)
 8621      2 gst-plugin-scann RET   netbsd32____lwp_park60 -1 errno 4 Interrupted system call
 8621      1 gst-plugin-scann NAMI  "gst-plugin-scann.core"
 
 
 You can repeat that outside of the cheese build by running
 gst-inspect-1.0 when the gnome-video-effects packages is also
 installed.
 
 Here is a stack trace extracted from the coredump:
 
 (gdb) where
 #0  0x6f6a1610 in f0r_get_param_value ()
    from /usr/pkg/lib/frei0r-1/lightgraffiti.so
 #1  0x795936b0 in gst_frei0r_klass_install_properties ()
    from /usr/pkg/lib/gstreamer-1.0/libgstfrei0r.so
 #2  0x79594a30 in gst_frei0r_filter_class_init ()
    from /usr/pkg/lib/gstreamer-1.0/libgstfrei0r.so
 #3  0x7bce6e58 in g_type_class_ref () from /usr/pkg/lib/libgobject-2.0.so.0
 #4  0x7bdbd428 in gst_element_register (plugin=0x7a52a178, 
     name=0x7a5273c0 "frei0r-filter-light-graffiti", rank=0, type=2060416288)
     at gstelementfactory.c:240
 #5  0x79594d94 in gst_frei0r_filter_register ()
    from /usr/pkg/lib/gstreamer-1.0/libgstfrei0r.so
 #6  0x79593124 in register_plugins ()
    from /usr/pkg/lib/gstreamer-1.0/libgstfrei0r.so
 #7  0x79593410 in plugin_init ()
    from /usr/pkg/lib/gstreamer-1.0/libgstfrei0r.so
 #8  0x7bdecdb0 in gst_plugin_register_func (plugin=0x7a52a178, 
     desc=0x795a93a0 <gst_plugin_desc>, user_data=0x0) at gstplugin.c:525
 #9  0x7bdef32c in _priv_gst_plugin_load_file_for_registry (
     filename=filename@entry=0x7b81c60c "/usr/pkg/lib/gstreamer-1.0/libgstfrei0r.so", registry=0x7bd1f860, registry@entry=0x0, error=error@entry=0x0)
     at gstplugin.c:886
 #10 0x7bdeffe0 in gst_plugin_load_file (
     filename=filename@entry=0x7b81c60c "/usr/pkg/lib/gstreamer-1.0/libgstfrei0r.so", error=error@entry=0x0) at gstplugin.c:682
 #11 0x7bdf2de4 in do_plugin_load (tag=89, 
     filename=0x7b81c60c "/usr/pkg/lib/gstreamer-1.0/libgstfrei0r.so", 
     l=<optimized out>) at gstpluginloader.c:728
 #12 handle_rx_packet (payload_len=<optimized out>, 
     payload=0x7b81c60c "/usr/pkg/lib/gstreamer-1.0/libgstfrei0r.so", tag=89, 
     pack_type=<optimized out>, l=<optimized out>) at gstpluginloader.c:836
 #13 read_one (l=0x7bb4d1c8) at gstpluginloader.c:1006
 #14 exchange_packets (l=l@entry=0x7bb4d1c8) at gstpluginloader.c:1034
 #15 0x7bdf3e80 in _gst_plugin_loader_client_run () at gstpluginloader.c:583
 
 
 Removing lightgraffiti.so avoids the crash.
 
    0x6f6a15bc <f0r_get_param_value>:        ldr     r3, [pc, #172]  ; 0x6f6a1670 <f0r_get_param_value+180>
    0x6f6a15c0 <f0r_get_param_value+4>:      add     r12, r2, r2, lsl #1
    0x6f6a15c4 <f0r_get_param_value+8>:      add     r3, pc, r3
    0x6f6a15c8 <f0r_get_param_value+12>:     ldr     r3, [r3, #88]   ; 0x58
    0x6f6a15cc <f0r_get_param_value+16>:     add     r12, r2, r12, lsl #2
    0x6f6a15d0 <f0r_get_param_value+20>:     add     r3, r3, r12, lsl #2
    0x6f6a15d4 <f0r_get_param_value+24>:     ldr     r0, [r0, #16]
    0x6f6a15d8 <f0r_get_param_value+28>:     ldr     r3, [r3, #48]   ; 0x30
    0x6f6a15dc <f0r_get_param_value+32>:     ldr     r2, [r0, r2, lsl #2]
    0x6f6a15e0 <f0r_get_param_value+36>:     mov     r12, r1
    0x6f6a15e4 <f0r_get_param_value+40>:     cmp     r3, #4
    0x6f6a15e8 <f0r_get_param_value+44>:     addls   pc, pc, r3, lsl #2
    0x6f6a15ec <f0r_get_param_value+48>:     b       0x6f6a160c <f0r_get_param_value+80>
    0x6f6a15f0 <f0r_get_param_value+52>:     b       0x6f6a1610 <f0r_get_param_value+84>
    0x6f6a15f4 <f0r_get_param_value+56>:     b       0x6f6a1634 <f0r_get_param_value+120>
    0x6f6a15f8 <f0r_get_param_value+60>:     b       0x6f6a1640 <f0r_get_param_value+132>
    0x6f6a15fc <f0r_get_param_value+64>:     b       0x6f6a164c <f0r_get_param_value+144>
    0x6f6a1600 <f0r_get_param_value+68>:     b       0x6f6a1604 <f0r_get_param_value+72>
    0x6f6a1604 <f0r_get_param_value+72>:     ldr     r3, [r2]
    0x6f6a1608 <f0r_get_param_value+76>:     str     r3, [r1]
    0x6f6a160c <f0r_get_param_value+80>:     bx      lr
 => 0x6f6a1610 <f0r_get_param_value+84>:     vldr    d6, [r2]
    0x6f6a1614 <f0r_get_param_value+88>:     vldr    d7, [pc, #60]   ; 0x6f6a1658 <f0r_get_param_value+156>
    0x6f6a1618 <f0r_get_param_value+92>:     vcmpe.f64       d6, d7
    0x6f6a161c <f0r_get_param_value+96>:     vldr    d7, [pc, #60]   ; 0x6f6a1660 <f0r_get_param_value+164>
    0x6f6a1620 <f0r_get_param_value+100>:    vmrs    APSR_nzcv, fpscr
    0x6f6a1624 <f0r_get_param_value+104>:    vldr    d6, [pc, #60]   ; 0x6f6a1668 <f0r_get_param_value+172>
    0x6f6a1628 <f0r_get_param_value+108>:    vmovle.f64      d7, d6
    0x6f6a162c <f0r_get_param_value+112>:    vstr    d7, [r1]
    0x6f6a1630 <f0r_get_param_value+116>:    bx      lr
 
 
 The branch table at 0x6f6a15ec is a switch statement with entries for:
 
 default:
 F0R_PARAM_BOOL       0
 F0R_PARAM_DOUBLE     1
 F0R_PARAM_COLOR      2
 F0R_PARAM_POSITION   3
 F0R_PARAM_STRING     4
 
 and the parameter type in r3 is 0. A stray value in r6 points to
 the bool p_statsDifference which happens to be add an odd address.
 
 The code for FOR_PARAM_BOOL however tries to access the parameter with
 a vldr instruction which traps.
 
 
 Reason is that the code treats FOR_PARAM_BOOL as double:
 
 In frei0r.h:
 
 typedef double f0r_param_bool;
 
 In frei0r.hpp:
 
         case F0R_PARAM_BOOL :
           *static_cast<f0r_param_bool*>(param)
             = *static_cast<f0r_param_bool*>(ptr) > 0.5 ? 1.0 : 0.0;
 
 
 But the register_param function does not. A C++ type bool is registered
 as FOR_PARAM_BOOL and later accessed as a double.
 
     void register_param(bool& p_loc,
                         const std::string& name,
                         const std::string& desc)
     {     
       param_ptrs.push_back(&p_loc);
       s_params.push_back(param_info(name,desc,F0R_PARAM_BOOL));
     }       
 
 
 
 
 Greetings,
 -- 
                                 Michael van Elst
 Internet: mlelstv%serpens.de@localhost
                                 "A potential Snark may lurk in every tree."