Don't do this:
(gdb) bt
#0 0x00007f37ae667c40 in ?? () from /lib/x86_64-linux-gnu/libz.so.1
#1 0x00007f37ae668b38 in ?? () from /lib/x86_64-linux-gnu/libz.so.1
#2 0x00007f37ae669907 in deflate () from /lib/x86_64-linux-gnu/libz.so.1
#3 0x00007f37ae674c65 in compress2 () from /lib/x86_64-linux-gnu/libz.so.1
#4 0x000000000040cfe3 in zencode_scids (ctx=0xc1f118, scids=0x2599bc49 "\a\325{", len=176320) at gossipd/gossipd.c:218
#5 0x000000000040d0b3 in encode_short_channel_ids_end (encoded=0x7fff8f98d9f0, max_bytes=65490) at gossipd/gossipd.c:236
#6 0x000000000040dd28 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17290511, number_of_blocks=8) at gossipd/gossipd.c:576
#7 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17290511, number_of_blocks=16) at gossipd/gossipd.c:595
#8 0x000000000040ddee in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17290495, number_of_blocks=32) at gossipd/gossipd.c:596
#9 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17290495, number_of_blocks=64) at gossipd/gossipd.c:595
#10 0x000000000040ddee in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17290431, number_of_blocks=128) at gossipd/gossipd.c:596
#11 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17290431, number_of_blocks=256) at gossipd/gossipd.c:595
#12 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17290431, number_of_blocks=512) at gossipd/gossipd.c:595
#13 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17290431, number_of_blocks=1024) at gossipd/gossipd.c:595
#14 0x000000000040ddee in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17289408, number_of_blocks=2047) at gossipd/gossipd.c:596
#15 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17289408, number_of_blocks=4095) at gossipd/gossipd.c:595
#16 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17289408, number_of_blocks=8191) at gossipd/gossipd.c:595
#17 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17289408, number_of_blocks=16382) at gossipd/gossipd.c:595
#18 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17289408, number_of_blocks=32764) at gossipd/gossipd.c:595
#19 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17289408, number_of_blocks=65528) at gossipd/gossipd.c:595
#20 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17289408, number_of_blocks=131056) at gossipd/gossipd.c:595
#21 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17289408, number_of_blocks=262112) at gossipd/gossipd.c:595
#22 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17289408, number_of_blocks=524225) at gossipd/gossipd.c:595
#23 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17289408, number_of_blocks=1048450) at gossipd/gossipd.c:595
#24 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17289408, number_of_blocks=2096900) at gossipd/gossipd.c:595
#25 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17289408, number_of_blocks=4193801) at gossipd/gossipd.c:595
#26 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17289408, number_of_blocks=8387603) at gossipd/gossipd.c:595
#27 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=17289408, number_of_blocks=16775207) at gossipd/gossipd.c:595
#28 0x000000000040ddee in queue_channel_ranges (peer=0x3868fc8, first_blocknum=514201, number_of_blocks=33550414) at gossipd/gossipd.c:596
#29 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=514201, number_of_blocks=67100829) at gossipd/gossipd.c:595
#30 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=514201, number_of_blocks=134201659) at gossipd/gossipd.c:595
#31 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=514201, number_of_blocks=268403318) at gossipd/gossipd.c:595
#32 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=514201, number_of_blocks=536806636) at gossipd/gossipd.c:595
#33 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=514201, number_of_blocks=1073613273) at gossipd/gossipd.c:595
#34 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=514201, number_of_blocks=2147226547) at gossipd/gossipd.c:595
#35 0x000000000040ddc6 in queue_channel_ranges (peer=0x3868fc8, first_blocknum=514201, number_of_blocks=4294453094) at gossipd/gossipd.c:595
#36 0x000000000040df26 in handle_query_channel_range (peer=0x3868fc8, msg=0x37e0678 "\001\ao\342\214\n\266\361\263r\301\246\242F\256c\367O\223\036\203e\341Z\b\234h\326\031") at gossipd/gossipd.c:625
The cause was that converting a block number to an scid truncates it
at 24 bits. When we look through the index from (truncated number) to
(real end number) we get every channel, which is too large to encode,
so we iterate again.
This fixes both that problem, and also the issue that we'd end up
dividing into many empty sections until we get to the highest block
number. Instead, we just tack the empty blocks on to then end of the
final query.
(My initial version requested 0xFFFFFFFE blocks, but the dev code
which records what blocks were returned can't make a bitmap that big
on 32 bit).
Reported-by: George Vaccaro
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Rusty Russell
0ba547ee10