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by **Fuddl** » Mon Oct 02, 2006 6:50 pm

hi there!

a friend of mine noticed, that a nexuiz server cannot be found in the nexuiz server browser if the server was bound to an ip by the -ip command line parameter.
i checked this and also noticed, that the parameter -ip makes the nexuiz server segfault on amd64.

i didn't take any further steps to debug this behaviour, perhaps it's an already known bug?

cheers - fuddl

by **LordHavoc** » Tue Oct 03, 2006 5:04 am

Fuddl wrote:hi there!

a friend of mine noticed, that a nexuiz server cannot be found in the nexuiz server browser if the server was bound to an ip by the -ip command line parameter.
i checked this and also noticed, that the parameter -ip makes the nexuiz server segfault on amd64.

i didn't take any further steps to debug this behaviour, perhaps it's an already known bug?

cheers - fuddl

The networking never sends the IP address directly, so use of -ip has no effect on networking except which socket address is bound (to select a network card)...

So I really can't imagine how this would prevent it from showing up on the server browser unless it is failing to bind that address (in which case no networking would work, and consequently no one could manually connect to it).

Regarding a segfault on amd64, that's interesting, could you run in gdb or ddd (graphical gdb frontend that isn't a pain to use) or the emacs gdb frontend if you prefer, and tell me or div0 what place it crashes?

by **tChr** » Tue Oct 03, 2006 12:59 pm

It mught be that you are using a non standard port.. IIRC you wont find local games running on other port than 26000 unless they are public to a mster server.

by **Fuddl** » Wed Oct 04, 2006 10:40 pm

k, i compiled a non-stripped nexuiz-dedicated server binary and ran gdb on it, but, the output wasn't helpful to me - i really hope it helps you! the segfault applies to binaries compiled with both, gcc 3.4 and gcc 4.1. the following output is from a binary compiled with gcc 4.1

Code: Select all: fuddl@tittchen:~/saugsaug/nexuiz-2.1$ gdb ./nexuiz-dedicated core GNU gdb 6.4.90-debian Copyright (C) 2006 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "x86_64-linux-gnu"...Using host libthread_db library "/lib/libthread_db.so.1". warning: core file may not match specified executable file. Reading symbols from /lib/libm.so.6...done. Loaded symbols for /lib/libm.so.6 Reading symbols from /lib/libdl.so.2...done. Loaded symbols for /lib/libdl.so.2 Reading symbols from /lib/libc.so.6...done. Loaded symbols for /lib/libc.so.6 Reading symbols from /lib/ld-linux-x86-64.so.2...done. Loaded symbols for /lib64/ld-linux-x86-64.so.2 Reading symbols from /usr/lib/libz.so.1...done. Loaded symbols for /usr/lib/libz.so.1 Core was generated by `./nexuiz-dedicated -ip 192.168.1.20'. Program terminated with signal 11, Segmentation fault. #0 0x00002b7ed0a435e0 in strlen () from /lib/libc.so.6 (gdb) run -ip 192.168.1.20 Starting program: /home/fuddl/saugsaug/nexuiz-2.1/nexuiz-dedicated -ip 192.168.1.20 Console initialized. Nexuiz Linux 00:25:13 Oct 5 2006 Trying to load library... "libz.so.1" - loaded. Compressed files support enabled Added packfile data/common-spog.pk3 (26 files) Added packfile data/data20060905.pk3 (2867 files) Program received signal SIGSEGV, Segmentation fault. 0x00002ae03b2ad5e0 in strlen () from /lib/libc.so.6 (gdb) bt #0 0x00002ae03b2ad5e0 in strlen () from /lib/libc.so.6 #1 0x00002ae03b27f46c in vfprintf () from /lib/libc.so.6 #2 0x0000000000000001 in ?? () #3 0x00007fff6fc09070 in ?? () #4 0x00007fff6fc09000 in ?? () #5 0x00000000004f7f48 in qfont_table () #6 0x00007fff6fc09030 in ?? () #7 0x00007fff6fc08b20 in ?? () #8 0x00007fff6fc0d1d0 in ?? () #9 0x000000000050d770 in vm_m_numbuiltins () #10 0x00007fff6fc09050 in ?? () #11 0x0000000000000000 in ?? () (gdb)

also, here's the output of strace:

Code: Select all: fuddl@tittchen:~/saugsaug/nexuiz-2.1$ strace ./nexuiz-dedicated -ip 192.168.1.20 execve("./nexuiz-dedicated", ["./nexuiz-dedicated", "-ip", "192.168.1.20"], [/* 27 vars */]) = 0 uname({sys="Linux", node="tittchen", ...}) = 0 brk(0) = 0x3b30000 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2ab124e7f000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=78059, ...}) = 0 mmap(NULL, 78059, PROT_READ, MAP_PRIVATE, 3, 0) = 0x2ab124e81000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/libm.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\320=\0\0"..., 640) = 640 fstat(3, {st_mode=S_IFREG|0644, st_size=535696, ...}) = 0 mmap(NULL, 1581480, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x2ab124f80000 mprotect(0x2ab125002000, 1049000, PROT_NONE) = 0 mmap(0x2ab125101000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x81000) = 0x2ab125101000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/libdl.so.2", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\0\20\0\0"..., 640) = 640 fstat(3, {st_mode=S_IFREG|0644, st_size=10392, ...}) = 0 mmap(NULL, 1057000, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x2ab125103000 mprotect(0x2ab125105000, 1048808, PROT_NONE) = 0 mmap(0x2ab125204000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1000) = 0x2ab125204000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\200\305"..., 640) = 640 lseek(3, 624, SEEK_SET) = 624 read(3, "\4\0\0\0\20\0\0\0\1\0\0\0GNU\0\0\0\0\0\2\0\0\0\6\0\0\0"..., 32) = 32 fstat(3, {st_mode=S_IFREG|0755, st_size=1290408, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2ab125206000 mmap(NULL, 2349000, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x2ab125207000 mprotect(0x2ab125328000, 1165256, PROT_NONE) = 0 mmap(0x2ab125427000, 106496, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x120000) = 0x2ab125427000 mmap(0x2ab125441000, 14280, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x2ab125441000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2ab125445000 mprotect(0x2ab125427000, 94208, PROT_READ) = 0 arch_prctl(ARCH_SET_FS, 0x2ab1254456d0) = 0 munmap(0x2ab124e81000, 78059) = 0 rt_sigaction(SIGFPE, {SIG_IGN}, {SIG_DFL}, 8) = 0 fcntl(0, F_GETFL) = 0x8002 (flags O_RDWR|O_LARGEFILE) fcntl(0, F_SETFL, O_RDWR|O_NONBLOCK|O_LARGEFILE) = 0 brk(0) = 0x3b30000 brk(0x3b51000) = 0x3b51000 fcntl(1, F_GETFL) = 0x8802 (flags O_RDWR|O_NONBLOCK|O_LARGEFILE) fcntl(1, F_SETFL, O_RDWR|O_LARGEFILE) = 0 write(1, "Console initialized.\n", 21Console initialized. ) = 21 fcntl(1, F_SETFL, O_RDWR|O_NONBLOCK|O_LARGEFILE) = 0 fcntl(1, F_GETFL) = 0x8802 (flags O_RDWR|O_NONBLOCK|O_LARGEFILE) fcntl(1, F_SETFL, O_RDWR|O_LARGEFILE) = 0 write(1, "Nexuiz Linux 00:25:13 Oct 5 200"..., 34Nexuiz Linux 00:25:13 Oct 5 2006 ) = 34 fcntl(1, F_SETFL, O_RDWR|O_NONBLOCK|O_LARGEFILE) = 0 open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=78059, ...}) = 0 mmap(NULL, 78059, PROT_READ, MAP_PRIVATE, 3, 0) = 0x2ab124e81000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/libz.so.1", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P \0\0\0"..., 640) = 640 fstat(3, {st_mode=S_IFREG|0644, st_size=90024, ...}) = 0 mmap(NULL, 1136808, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x2ab125446000 mprotect(0x2ab12545c000, 1046696, PROT_NONE) = 0 mmap(0x2ab12555b000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x15000) = 0x2ab12555b000 close(3) = 0 munmap(0x2ab124e81000, 78059) = 0 fcntl(1, F_GETFL) = 0x8802 (flags O_RDWR|O_NONBLOCK|O_LARGEFILE) fcntl(1, F_SETFL, O_RDWR|O_LARGEFILE) = 0 write(1, "Trying to load library... \"libz."..., 48Trying to load library... "libz.so.1" - loaded. ) = 48 fcntl(1, F_SETFL, O_RDWR|O_NONBLOCK|O_LARGEFILE) = 0 fcntl(1, F_GETFL) = 0x8802 (flags O_RDWR|O_NONBLOCK|O_LARGEFILE) fcntl(1, F_SETFL, O_RDWR|O_LARGEFILE) = 0 write(1, "Compressed files support enabled"..., 33Compressed files support enabled ) = 33 fcntl(1, F_SETFL, O_RDWR|O_NONBLOCK|O_LARGEFILE) = 0 open("data/", O_RDONLY|O_NONBLOCK|O_DIRECTORY) = 3 fstat(3, {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 fcntl(3, F_SETFD, FD_CLOEXEC) = 0 getdents64(3, /* 6 entries */, 4096) = 184 getdents64(3, /* 0 entries */, 4096) = 0 close(3) = 0 open("data/common-spog.pk3", O_RDONLY) = 3 lseek(3, 0, SEEK_END) = 28724 lseek(3, 0, SEEK_SET) = 0 read(3, "PK\3\4\n\0\0\0\0\0\223k-,\0\0\0\0\0\0\0\0\0\0\0\0\t\0\25"..., 28724) = 28724 lseek(3, 26219, SEEK_SET) = 26219 read(3, "PK\1\2\27\3\n\0\0\0\0\0\223k-,\0\0\0\0\0\0\0\0\0\0\0\0"..., 2483) = 2483 fcntl(1, F_GETFL) = 0x8802 (flags O_RDWR|O_NONBLOCK|O_LARGEFILE) fcntl(1, F_SETFL, O_RDWR|O_LARGEFILE) = 0 write(1, "Added packfile data/common-spog."..., 47Added packfile data/common-spog.pk3 (26 files) ) = 47 fcntl(1, F_SETFL, O_RDWR|O_NONBLOCK|O_LARGEFILE) = 0 open("data/data20060905.pk3", O_RDONLY) = 4 lseek(4, 0, SEEK_END) = 186821992 lseek(4, 186756435, SEEK_SET) = 186756435 read(4, ",\0\0.\0\0\0\0\0\0\0\0\0 \200\244\201\271\3\34\ttextur"..., 65557) = 65557 mmap(NULL, 483328, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2ab124e81000 mmap(NULL, 233472, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2ab124ef7000 lseek(4, 186589113, SEEK_SET) = 186589113 read(4, "PK\1\2\24\0\24\0\0\0\10\0\353\266%5\320n\366\16\324\34"..., 232857) = 232857 munmap(0x2ab124ef7000, 233472) = 0 fcntl(1, F_GETFL) = 0x8802 (flags O_RDWR|O_NONBLOCK|O_LARGEFILE) fcntl(1, F_SETFL, O_RDWR|O_LARGEFILE) = 0 write(1, "Added packfile data/data20060905"..., 50Added packfile data/data20060905.pk3 (2867 files) ) = 50 fcntl(1, F_SETFL, O_RDWR|O_NONBLOCK|O_LARGEFILE) = 0 open("/home/fuddl/.nexuiz/data/", O_RDONLY|O_NONBLOCK|O_DIRECTORY) = 5 fstat(5, {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 fcntl(5, F_SETFD, FD_CLOEXEC) = 0 getdents64(5, /* 9 entries */, 4096) = 280 getdents64(5, /* 0 entries */, 4096) = 0 close(5) = 0 --- SIGSEGV (Segmentation fault) @ 0 (0) --- +++ killed by SIGSEGV (core dumped) +++ Process 20404 detached

by **divVerent** » Thu Oct 05, 2006 5:47 am

This doesn't look like a binary with debug info.

Can you try to "make sv-debug" and then run the resulting darkplaces-dedicated in gdb like this:

(gdb) run -nexuiz -ip 192.168.1.20

by **esteel** » Thu Oct 05, 2006 6:43 am

You can also try a 'make clean' first. I once had a problem that 'make debug' did not create a debug binary. Either i made some error or make did not recompile everything correctly.

by **Fuddl** » Thu Oct 05, 2006 9:37 am

hmpf, yeah... i know, not stripping isn't enough *selfslap*

k, compiled it unstripped and with debugging symbols and tried again. the backtrace looks the same as the segfault happens in the libc, not nexuiz itself.

here's my gdb session, with debugging symbols:

Code: Select all: fuddl@tittchen:~/saugsaug/nexuiz-2.1$ gdb ./darkplaces-dedicated core GNU gdb 6.4.90-debian Copyright (C) 2006 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "x86_64-linux-gnu"...Using host libthread_db library "/lib/libthread_db.so.1". warning: core file may not match specified executable file. Reading symbols from /lib/libm.so.6...done. Loaded symbols for /lib/libm.so.6 Reading symbols from /lib/libdl.so.2...done. Loaded symbols for /lib/libdl.so.2 Reading symbols from /lib/libc.so.6...done. Loaded symbols for /lib/libc.so.6 Reading symbols from /lib/ld-linux-x86-64.so.2...done. Loaded symbols for /lib64/ld-linux-x86-64.so.2 Reading symbols from /usr/lib/libz.so.1...done. Loaded symbols for /usr/lib/libz.so.1 Core was generated by `./darkplaces-dedicated -ip 192.168.1.20'. Program terminated with signal 11, Segmentation fault. #0 0x00002b98f138a5e0 in strlen () from /lib/libc.so.6 (gdb) break main Breakpoint 1 at 0x402169: file sys_linux.c, line 243. (gdb) run -ip 192.168.1.20 Starting program: /home/fuddl/saugsaug/nexuiz-2.1/darkplaces-dedicated -ip 192.168.1.20 Breakpoint 1, main (argc=3, argv=0x7fff9c7bffd8) at sys_linux.c:243 243 signal(SIGFPE, SIG_IGN); (gdb) n 245 com_argc = argc; (gdb) n 246 com_argv = (const char **)argv; (gdb) n 249 fcntl(0, F_SETFL, fcntl (0, F_GETFL, 0) | FNDELAY); (gdb) n 252 Host_Main(); (gdb) n Console initialized. Nexuiz Linux 11:26:28 Oct 5 2006 Trying to load library... "libz.so.1" - loaded. Compressed files support enabled Added packfile data/common-spog.pk3 (26 files) Added packfile data/data20060905.pk3 (2867 files) Program received signal SIGSEGV, Segmentation fault. 0x00002b1c0e6f85e0 in strlen () from /lib/libc.so.6 (gdb) bt #0 0x00002b1c0e6f85e0 in strlen () from /lib/libc.so.6 #1 0x00002b1c0e6ca46c in vfprintf () from /lib/libc.so.6 #2 0x00007fff9c7bbb20 in ?? () #3 0x00002b1c0e6eeeb5 in _IO_default_xsputn () from /lib/libc.so.6 #4 0x00007fff9c7bbb10 in ?? () #5 0x00007fff9c7bbb90 in ?? () #6 0x00000000005707ee in gamemode_info () #7 0x00007fff9c7bb630 in ?? () #8 0x00007fff9c7bfd20 in ?? () #9 0x0000000000581770 in vm_m_numbuiltins () #10 0x00007fff9c7bbb60 in ?? () #11 0x0000000000000000 in ?? () (gdb)

looks like a strlen() call gets a wrong pointer, which leads to the segfault in libc

by **divVerent** » Thu Oct 05, 2006 10:54 am

Can you trace further? I cannot reproduce it.

by **Fuddl** » Thu Oct 05, 2006 8:59 pm

as i didn't find much out by gdb, i tried some old-school printf() debugging.

the engine seems to fail in NetConn_Init();, called from host.c:933... that's all i found out this evening, i don't have time for more debugging atm, sorry

by **LordHavoc** » Sat Oct 07, 2006 12:59 am

Fuddl wrote:as i didn't find much out by gdb, i tried some old-school printf() debugging.

the engine seems to fail in NetConn_Init();, called from host.c:933... that's all i found out this evening, i don't have time for more debugging atm, sorry

I'd recommend installing a -debuginfo package for your libc, then you should get some proper function names...

I do wonder about that backtrace because most of those are libc functions, and extremely few libc functions involve a callback of any kind, so the idea that they are in the stack inbetween DP functions makes me think it is a recursive error handler of some kind.

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