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Hi all,<br>
I got this message from /var/log/messages when I use tsung:<br>
<blockquote><span class="ul-threaded"
style="margin: 0.5em 0pt 0pt -20px;"><span class="text-cell">May 24
14:55:26 dev-3 kernel: [264002.592197] beam[8449]:
segfault at 0 ip 0000000000437e10 sp 00007fffce250948 error 4 in
beam[400000+174000]</span></span><br>
</blockquote>
The process is like this one:<br>
<blockquote><span class="ul-threaded"
style="margin: 0.5em 0pt 0pt -20px;"><span class="text-cell">sunny
4796 0.9 1.8 134320 76444 ? Sl
10:58
0:00 /usr/lib/erlang/erts-5.7.2/bin/beam -A 256 -P 250000 -- -root
/usr/lib/erlang -progname erl -- -home /home/sunny -noshell -noinput
-noshell -noinput -master <a
href="http://erlang.2086793.n4.nabble.com/user/SendEmail.jtp?type=node&node=2229475&i=0"
target="_top" rel="nofollow">[hidden email]</a>
-name <a
href="http://erlang.2086793.n4.nabble.com/user/SendEmail.jtp?type=node&node=2229475&i=1"
target="_top" rel="nofollow">[hidden email]</a> -s slave
slave_start <a
href="http://erlang.2086793.n4.nabble.com/user/SendEmail.jtp?type=node&node=2229475&i=2"
target="_top" rel="nofollow">[hidden email]</a>
slave_waiter_2 -rsh ssh -noshell
-noinput -setcookie tsung -smp disable</span></span><br>
</blockquote>
(Never mind the process number, they're different because the latter is
the command when I reproduced the problem.)<br>
<br>
And the system is:<br>
<blockquote>sunny@dev-3:~$ uname -a<br>
Linux dev-3 2.6.31-14-server #48-Ubuntu SMP Fri Oct 16 15:07:34 UTC
2009 x86_64 GNU/Linux<br>
<br>
sunny@dev-3:~$ dmesg | grep CPU<br>
[ 0.000000] SMP: Allowing 32 CPUs, 24 hotplug CPUs<br>
[ 0.000000] NR_CPUS:64 nr_cpumask_bits:64 nr_cpu_ids:32 nr_node_ids:2<br>
[ 0.000000] PERCPU: Remapped at ffffc90000000000 with large pages,
static data 90720 bytes<br>
[ 0.000000] Initializing CPU#0<br>
[ 0.000000] SLUB: Genslabs=14, HWalign=64, Order=0-3, MinObjects=0,
CPUs=32, Nodes=2<br>
[ 0.023346] CPU: Physical Processor ID: 1<br>
[ 0.023347] CPU: Processor Core ID: 0<br>
[ 0.023351] CPU: L1 I cache: 32K, L1 D cache: 32K<br>
[ 0.023353] CPU: L2 cache: 256K<br>
[ 0.023355] CPU: L3 cache: 4096K<br>
[ 0.023358] CPU 0/0x10 -> Node 0<br>
[ 0.023361] mce: CPU supports 9 MCE banks<br>
[ 0.023373] CPU0: Thermal monitoring enabled (TM1)<br>
[ 0.023377] CPU 0 MCA banks CMCI:2 CMCI:3 CMCI:5 CMCI:6 CMCI:8<br>
[ 0.131977] CPU0: Intel(R) Xeon(R) CPU E5504 @ 2.00GHz
stepping 05<br>
</blockquote>
<span class="text-cell">I attatched the running process by gdb, and
here is the result:<br>
<blockquote>Program received signal SIGSEGV, Segmentation fault.<br>
unlink_free_block (allctr=0x7ad480, block=0x0) at
beam/erl_goodfit_alloc.c:453<br>
453 Uint sz = BLK_SZ(blk);<br>
(gdb) whe<br>
#0 unlink_free_block (allctr=0x7ad480, block=0x0) at
beam/erl_goodfit_alloc.c:453<br>
#1 0x0000000000437fd6 in get_free_block (allctr=0x7ad480,
size=<value optimized out>, cand_blk=0x0, cand_size=0)<br>
at beam/erl_goodfit_alloc.c:421<br>
#2 0x00000000004322c6 in mbc_alloc_block (allctr=0x7ad480, size=72) at
beam/erl_alloc_util.c:631<br>
#3 mbc_alloc (allctr=0x7ad480, size=72) at beam/erl_alloc_util.c:758<br>
#4 0x00000000004b1697 in erts_alloc () at beam/erl_alloc.h:179<br>
#5 exit_async () at beam/erl_async.c:132<br>
#6 0x000000000043c13d in system_cleanup (exit_code=<value optimized
out>) at beam/erl_init.c:1306<br>
#7 0x000000000043c443 in erl_exit (n=0, fmt=0x54649c "") at
beam/erl_init.c:1380<br>
#8 0x000000000045d042 in halt_0 (A__p=<value optimized out>) at
beam/bif.c:3319<br>
#9 0x00000000004d081f in process_main () at beam/beam_emu.c:2008<br>
#10 0x000000000043d56c in erl_start (argc=34, argv=<value optimized
out>) at beam/erl_init.c:1233<br>
#11 0x00000000004269b9 in main (argc=8049792, argv=0x0) at
sys/unix/erl_main.c:29<br>
(gdb) f 1<br>
#1 0x0000000000437fd6 in get_free_block (allctr=0x7ad480,
size=<value optimized out>, cand_blk=0x0, cand_size=0)<br>
at beam/erl_goodfit_alloc.c:421<br>
421 unlink_free_block(allctr, blk);<br>
(gdb) l 421<br>
416 /* We are guaranteed to find a block that fits in this
bucket */<br>
417 blk = search_bucket(allctr, min_bi, size);<br>
418 ASSERT(blk);<br>
419 if (cand_blk && cand_size <= BLK_SZ(blk))<br>
420 return NULL; /* cand_blk was better */<br>
421 unlink_free_block(allctr, blk);<br>
422 return blk;<br>
423 }<br>
424 <br>
425 <br>
(gdb) <br>
</blockquote>
As the running process use the no-debug symbol version beam, I guess
the ASSERT in line:418 does not work. So I dig in<br>
<blockquote>(gdb) p allctr<br>
$1 = (Allctr_t *) 0x7ad480<br>
(gdb) p min_bi<br>
$2 = <value optimized out><br>
(gdb) p size<br>
$3 = <value optimized out><br>
(gdb) p *allctr<br>
$4 = {name_prefix = 0x534227 "sl_", alloc_no = 3, name = {alloc = 0,
realloc = 0, free = 0}, <br>
vsn_str = 0x53602f "2.1", t = 0, ramv = 0, sbc_threshold = 524288,
sbc_move_threshold = 80, <br>
mbc_move_threshold = 50, main_carrier_size = 131072, max_mseg_sbcs =
256, max_mseg_mbcs = 5, <br>
largest_mbc_size = 10485760, smallest_mbc_size = 1048576,
mbc_growth_stages = 10, mseg_opt = {cache = 1, <br>
preserv = 1, abs_shrink_th = 4145152, rel_shrink_th = 80},
mbc_header_size = 32, sbc_header_size = 32, <br>
min_mbc_size = 16384, min_mbc_first_free_size = 4096, min_block_size
= 32, mbc_list = {first = 0x7f4f93a5d010, <br>
last = 0x7f4f93a5d010}, sbc_list = {first = 0x0, last = 0x0},
main_carrier = 0x7f4f93a5d010, <br>
get_free_block = 0x437f40 <get_free_block>, link_free_block =
0x437d00 <link_free_block>, <br>
unlink_free_block = 0x437e10 <unlink_free_block>, info_options
= 0x438480 <info_options>, <br>
get_next_mbc_size = 0x430e40 <get_next_mbc_size>, creating_mbc
= 0x438100 <update_last_aux_mbc>, <br>
destroying_mbc = 0x438100 <update_last_aux_mbc>, init_atoms =
0x4385c0 <init_atoms>, mutex = {mtx = {pt_mtx = {<br>
__data = {__lock = 0, __count = 0, __owner = 0, __nusers = 0,
__kind = 0, __spins = 0, __list = {<br>
__prev = 0x0, __next = 0x0}}, __size = '\000' <repeats
39 times>, __align = 0}, is_rec_mtx = 0, <br>
prev = 0x0, next = 0x0}}, thread_safe = 0, ts_list = {prev = 0x0,
next = 0x0}, atoms_initialized = 0, <br>
stopped = 0, calls = {this_alloc = {giga_no = 0, no = 2460},
this_free = {giga_no = 0, no = 2458}, <br>
this_realloc = {giga_no = 0, no = 0}, mseg_alloc = {giga_no = 0, no
= 0}, mseg_dealloc = {giga_no = 0, no = 0}, <br>
mseg_realloc = {giga_no = 0, no = 0}, sys_alloc = {giga_no = 0, no
= 1}, sys_free = {giga_no = 0, no = 0}, <br>
sys_realloc = {giga_no = 0, no = 0}}, sbcs = {curr_mseg = {no = 0,
size = 0}, curr_sys_alloc = {no = 0, <br>
size = 0}, max = {no = 0, size = 0}, max_ever = {no = 0, size =
0}, blocks = {curr = {no = 0, size = 0}, <br>
max = {no = 0, size = 0}, max_ever = {no = 0, size = 0}}}, mbcs =
{curr_mseg = {no = 0, size = 0}, <br>
curr_sys_alloc = {no = 1, size = 131112}, max = {no = 1, size =
131112}, max_ever = {no = 0, size = 0}, <br>
blocks = {curr = {no = 4, size = 384}, max = {no = 144, size =
13848}, max_ever = {no = 0, size = 0}}}}<br>
(gdb)</blockquote>
</span>I've discussed this in erlang-questions mailling list with
Mikael Pettersson( thanks Mikael ):<br>
<blockquote><a class="moz-txt-link-freetext" href="http://erlang.2086793.n4.nabble.com/beam-8449-segfault-at-0-ip-0000000000437e10-sp-00007fffce250948-error-4-in-beam-400000-174000-td2228295.html#a2244144">http://erlang.2086793.n4.nabble.com/beam-8449-segfault-at-0-ip-0000000000437e10-sp-00007fffce250948-error-4-in-beam-400000-174000-td2228295.html#a2244144</a><br>
</blockquote>
It looks like I should ask the question here. Does anyone have any idea
on this problem? TIA.<br>
<br>
Eric<br>
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