Follow-up Comment #4, bug #18005 (project freeciv):
Here's a backtrace of my reproduction case (trunk r19594 + patch #2627). I
haven't analysed it yet.
#0 0x7fd09fb667bb in raise (sig=value optimised out)
at ../nptl/sysdeps/unix/sysv/linux/pt-raise.c:42
No locals.
#1 0x0056a86f in fc_assert_fail (file=0x5d70ed bitvector.c,
function=0x5d725e dbv_isset, line=120, assertion=value optimised out,
message=0x0) at log.c:491
level = LOG_FATAL
#2 0x0057fd9e in dbv_isset (pdbv=value optimised out,
bit=value optimised out) at bitvector.c:120
__FUNCTION__ = dbv_isset
#3 0x00562923 in tile_get_known (ptile=0x8d03a90,
pplayer=0x76872c0)
at tile.c:388
No locals.
#4 0x004c306a in base_city_can_work_tile (restriction=0x76872c0,
pcity=0x8d75bb0, ptile=0x8d03a90) at city.c:1325
powner = 0x76872c0
city_map_x = 5
city_map_y = 5
#5 0x004386ca in find_city_or_settler_near_tile (ptile=0x8cfe1b0,
punit=0x7fff426988b8) at mapview_common.c:2227
tile1 = value optimised out
_x = 5
_y = 10
_x_y_index = 75
closest_city = 0x0
pcity = value optimised out
closest_settler = value optimised out
best_settler = 0x270
__FUNCTION__ = find_city_or_settler_near_tile
#6 0x0045a94b in fill_city_overlays_sprite_array (
t=value optimised out, sprs=value optimised out,
layer=value optimised out, ptile=0x8cfe1b0, pedge=value optimised
out,
pcorner=value optimised out, punit=0x0, pcity=0x0, citymode=0x0)
at tilespec.c:3738
pwork = 0x0
city_x = 0
NUM_CITY_COLORS = value optimised out
psettler = value optimised out
city_y = 16282160
#7 fill_sprite_array (t=value optimised out, sprs=value optimised out,
layer=value optimised out, ptile=0x8cfe1b0, pedge=value optimised
out,
pcorner=value optimised out, punit=0x0, pcity=0x0, citymode=0x0)
at tilespec.c:4641
tileno = value optimised out
tspecial_near = {{vec = 00}, {vec = 00}, {vec = 00}, {
vec = 00}, {vec = 00}, {vec = 00b}, {vec = 00}, {
vec = 00}}
tspecial = {vec = 00}
tterrain_near = {0x92f478, 0x92f478, 0x92f478, 0x92f478, 0x92f478,
0x92f478, 0x92f478, 0x92f478}
pterrain = value optimised out
owner = value optimised out
__FUNCTION__ = fill_sprite_array
#8 0x0043c0f9 in put_one_element (pcanvas=0xf87230,
layer=value optimised out, ptile=0x8cfe1b0, pedge=value optimised
out,
pcorner=value optimised out, punit=value optimised out, pcity=0x0,
canvas_x=-68, canvas_y=0, citymode=0x0) at mapview_common.c:952
tile_sprs = {{foggable = false, sprite = 0x5c20440, offset_x = 0,
offset_y = -24}, {foggable = false, sprite = 0x3db4cb0,
offset_x = 19, offset_y = -6}, {foggable = false,
sprite = 0xffb2c0, offset_x = 0, offset_y = -24}, {
foggable = false, sprite = 0x1495ef0, offset_x = 0,
offset_y = -24}, {foggable = false, sprite = 0x1495f30,
offset_x = 0, offset_y = -24}, {foggable = false,
sprite = 0x1495ef0, offset_x = 0, offset_y = -24}, {
foggable = false, sprite = 0x1495ef0, offset_x = 0,
offset_y = -24}, {foggable = false, sprite = 0xfa9a50,
offset_x = 0, offset_y = 0}, {foggable = 152,
sprite = 0x7fd0a42f54e0, offset_x = -47098187, offset_y = 0}, {
foggable = 34, sprite = 0x0, offset_x = -1540521528,
offset_y = 32720}, {foggable = 5, sprite = 0x0, offset_x = 1,
offset_y = 0}, {foggable = 228, sprite = 0xf0,
offset_x = 1114213168, offset_y = 32767}, {foggable = false,
sprite = 0x7fd0a42d98d0, offset_x = 1114213544, offset_y =
32767},
{foggable = 87, sprite = 0xe943b264, offset_x = -1542425513,
offset_y = 32720}, {foggable = false, sprite = 0x3a50ec9,
offset_x = 36, offset_y = 0}, {foggable = 44, sprite = 0x0,
offset_x = 1114213168, offset_y = 32767}, {foggable = 224,
sprite = 0x7fd0a2f7bab8, offset_x = -2147483648, offset_y = 0},
{
foggable = false, sprite = 0x9f378d0, offset_x = 2, offset_y =
0},
{foggable = 16, sprite = 0x7fd0a42ee000, offset_x = -1540399104,
offset_y = 32720}, {foggable = false, sprite = 0x0,
offset_x = -1540396640, offset_y = 32720}, {foggable = 115,
sprite = 0x7fd0a2f7bed8, offset_x = -1556416024,
offset_y = 32720}, {foggable = false, sprite = 0x10029,
offset_x = -1542408303, offset_y = 32720}, {foggable = 5,
sprite = 0x7fd0a42f6358, offset_x = 1114213600, offset_y =
32767},
{foggable = false, sprite = 0x7fff42698d08, offset_x = -1540399104,
offset_y = 32720}, {foggable = 100, sprite =
