Assertion failed... function arena_run_reg_dalloc

I get following message on today's (May 21) -CURRENT with up-to-date
jpilot from ports:

Assertion failed: ((run->regs_mask[elm] & (1 << bit)) == 0), function
arena_run_reg_dalloc, file /usr/src/lib/libc/stdlib/malloc.c, line 1638.

Program received signal SIGABRT, Aborted.
0x28adbf97 in kill () from /lib/libc.so.6

Code leading to this is as follows:

Breakpoint 1, get_inline_pixbuf_data.0 () at jpilot.c:1358
1358       pixbuf = gdk_pixbuf_new_from_xpm_data(xpm_icon_data);
1360          return NULL;
1359       if (!pixbuf)
1362       if (gdk_pixbuf_get_width(pixbuf)  != icon_size ||
1362       if (gdk_pixbuf_get_width(pixbuf)  != icon_size ||
1370       pixdata = (GdkPixdata*)g_malloc(sizeof(GdkPixdata));
1371       gdk_pixdata_from_pixbuf(pixdata, pixbuf, FALSE);
1370       pixdata = (GdkPixdata*)g_malloc(sizeof(GdkPixdata));
1371       gdk_pixdata_from_pixbuf(pixdata, pixbuf, FALSE);
1372       data = gdk_pixdata_serialize(pixdata, &len);
1374       fprintf(stderr, "pixbuf pointer is %04x\n", pixbuf);
pixbuf pointer is 8292f18
1375       g_free(pixbuf);
Assertion failed: ((run->regs_mask[elm] & (1 << bit)) == 0), function
arena_run_reg_dalloc, file /usr/src/lib/libc/stdlib/malloc.c, line 1638.

Program received signal SIGABRT, Aborted.
0x28adbf97 in kill () from /lib/libc.so.6

Stack trace is:

(gdb) bt
#0  0x28adbf97 in kill () from /lib/libc.so.6
#1  0x289df7c7 in raise () from /lib/libpthread.so.2
#2  0x28adaabc in abort () from /lib/libc.so.6
#3  0x28ac31b6 in __assert () from /lib/libc.so.6
#4  0x28a6548d in reallocf () from /lib/libc.so.6
#5  0x28a67b19 in free () from /lib/libc.so.6
#6  0x287f38b1 in g_free () from /usr/local/lib/libglib-2.0.so.0
#7  0x0807cf6a in get_inline_pixbuf_data.0 () at jpilot.c:1375
#8  0x0807d4cd in get_main_menu (window=0x82a5028, menubar=0xbfbfdee0,
plugin_list=0x82b0830)
    at jpilot.c:1382
#9  0x0807f0eb in main (argc=1, argv=0xbfbfe770) at jpilot.c:2443

Malloc flags are:

lrwxr-xr-x  1 root  wheel  3 May 21 21:32 /etc/malloc.conf -> ajZ

Since pointer does not look unreasonable, I would really appreciate any
suggestion on why is this specific assertion was triggered. That would
allow me to look for the culprit.

I would be happy to provide any additional information.

-- 
Alexandre Kovalenko (Олександр Коваленко)