Hello Burnhard,
On 2018-12-15 9:02 a.m., Bernhard Übelacker wrote:
Hello Anton,
On Fri, 14 Dec 2018 16:34:23 -0500 Anton Avramov <lu...@lukav.com> wrote:
Hello Bernhard,
Well no. I've actually installed. apt install
libmariadbclient18=10.1.26-0+deb9u1 libmariadbclient18-dbgsym
(gdb) display/i $pc
2: x/i $pc
=> 0x7ffff479eccc <mysql_stmt_bind_result+172>: movzbl 0x451(%rax),%eax
At this instruction $rax seems to contain the address stored in stmt->mysql.
This address seems to be invalid in your process.
And therefore accessing the options member crashes.
Could you please add the output of following commands, when the crash happened:
print/x $rax
print stmt->mysql
print stmt
set print pretty on
print *stmt
print *stmt->mysql
set print pretty off
up
print
conn_.statements_[isc::dhcp::MySqlHostDataSourceImpl::GET_HOST_SUBID4_DHCPID]
up
x/6xb identifier_begin
Here is the output of the requested commands:
(gdb) print/x $rax
$7 = 0x0
(gdb) print stmt->mysql
$8 = (MYSQL *) 0x0
(gdb) print stmt
$9 = (MYSQL_STMT *) 0x5555558f6be8
(gdb) set print pretty on
(gdb) print *stmt
$10 = {
mem_root = {
free = 0x5555558f6f28,
used = 0x5555558f9cb8,
pre_alloc = 0x5555558f6f28,
min_malloc = 32,
block_size = 2009,
block_num = 6,
first_block_usage = 0,
error_handler = 0x0
},
list = {
prev = 0x0,
next = 0x5555558f2c70,
data = 0x5555558f6be8
},
mysql = 0x0,
params = 0x5555558f9cd0,
bind = 0x5555558f9e20,
fields = 0x5555558f7770,
result = {
data = 0x0,
embedded_info = 0x0,
alloc = {
free = 0x5555558f8c88,
used = 0x0,
pre_alloc = 0x5555558f8c88,
min_malloc = 24,
block_size = 4057,
block_num = 4,
first_block_usage = 0,
error_handler = 0x0
},
rows = 0,
fields = 0,
---Type <return> to continue, or q <return> to quit---
extension = 0x0
},
data_cursor = 0x0,
read_row_func = 0x7ffff479d630 <stmt_read_row_no_result_set>,
affected_rows = 18446744073709551615,
insert_id = 0,
stmt_id = 4269,
flags = 0,
prefetch_rows = 1,
server_status = 2,
last_errno = 2013,
param_count = 3,
field_count = 18,
state = MYSQL_STMT_PREPARE_DONE,
last_error = "Lost connection to MySQL server during query", '\000'
<repeats 467 times>,
sqlstate = "HY000",
send_types_to_server = 1 '\001',
bind_param_done = 1 '\001',
bind_result_done = 1 '\001',
unbuffered_fetch_cancelled = 0 '\000',
update_max_length = 0 '\000',
extension = 0x5555558e7948
}
(gdb) print *stmt->mysql
Cannot access memory at address 0x0
(gdb) set print pretty off
(gdb) up
#1 0x00007ffff7a9ed19 in
isc::dhcp::MySqlHostDataSourceImpl::getHostCollection (this=0x5555558d6840,
stindex=isc::dhcp::MySqlHostDataSourceImpl::GET_HOST_SUBID4_DHCPID,
bind=0x7fffffffd340, exchange=...,
result=std::vector of length 0, capacity 0, single=true)
at ../../../../src/lib/dhcpsrv/mysql_host_data_source.cc:2262
2262 ../../../../src/lib/dhcpsrv/mysql_host_data_source.cc: Няма
такъв файл или директория.
(gdb) print
conn_.statements_[isc::dhcp::MySqlHostDataSourceImpl::GET_HOST_SUBID4_DHCPID]
$11 = (st_mysql_stmt *) 0x5555558f6be8
(gdb) up
#2 0x00007ffff7a9f540 in isc::dhcp::MySqlHostDataSourceImpl::getHost
(this=0x5555558d6840,
subnet_id=@0x7fffffffd8ac: 1, identifier_type=@0x555555883830:
isc::dhcp::Host::IDENT_HWADDR,
identifier_begin=0x555555834300 "\b", identifier_len=6,
stindex=isc::dhcp::MySqlHostDataSourceImpl::GET_HOST_SUBID4_DHCPID,
exchange=...)
at ../../../../src/lib/dhcpsrv/mysql_host_data_source.cc:2345
2345 in ../../../../src/lib/dhcpsrv/mysql_host_data_source.cc
(gdb) x/6xb identifier_begin
0x555555834300: 0x08 0x00 0x27 0x04 0xcc 0x0e
The last line should output 6 bytes showing the MAC address of the
requesting client. Maybe you could check if that crash is
triggered always by the same client or kind of client.
Each time the identifier is different, so I would say it is not caused
by a particular client.
The clients are identical dhclient that is the default with debian
I looked through upstream git history and commits [1] and [2] might be
related: they disable automatic reconnects.
No such commit seem to have reached the stretch version of kea-dhcp:
./isc-kea-1.1.0/src/lib/dhcpsrv/mysql_connection.cc:138: my_bool
auto_reconnect = MLM_TRUE;
Hmmm ... but if you disable autoreconnect, doesn't this means each time
you restart your database server for any reason your dhcp server would
become in a not working state and it would require restart also?
Kind regards,
Bernhard
Thank you very much for all your effort.
Best regards.
(gdb) list libmysql.c:4134
4129 field->type, param_count);
4130 DBUG_RETURN(1);
4131 }
4132 }
4133 stmt->bind_result_done= BIND_RESULT_DONE;
4134 if (stmt->mysql->options.report_data_truncation)
4135 stmt->bind_result_done|= REPORT_DATA_TRUNCATION;
4136
4137 DBUG_RETURN(0);
4138 }
[1]
https://gitlab.isc.org/isc-projects/kea/commit/9881ef6d772f27de82c048e198ba0ff9e71b9351
[2]
https://gitlab.isc.org/isc-projects/kea/commit/6b278a3f54ecf6bd6e2d381047a9eced4bf165f5
