1
0
mirror of https://github.com/MariaDB/server.git synced 2025-08-08 11:22:35 +03:00
Files
mariadb/mysql-test/lib/My/CoreDump.pm
Marko Mäkelä 9f8fc983d5 MDEV-30242 MTR fails to report stack traces of all threads by default
An unfortunate change to the default behavior of the handling of
core dumps was implemented in
commit e9be5428a2
by making MTR_PRINT_CORE=small the default value, that is, to
only display the stack trace of one thread in crash reports.
Many if not most failures that occur in regression tests are
sporadic and involve race conditions or deadlocks. To be able to
analyze such failures, having the stack traces of all active threads
is a must, because CI environments typically do not save any core dumps.

While the environment variable MTR_PRINT_CORE could be set in CI
environments to compensate for the unfortunate change, it is better
to revert to the old default (dumping all threads) so that
no explicit action will be required from maintainers of independent
CI systems. In that case, if something fails once in a blue moon,
we can have some hope of diagnosing it based on the output.

We fix this regression by defaulting the unset environment variable
MTR_PRINT_CORE to "medium".
2022-12-16 09:59:09 +02:00

544 lines
15 KiB
Perl

# -*- cperl -*-
# Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA
package My::CoreDump;
use strict;
use Carp;
use My::Platform;
use Text::Wrap;
use Data::Dumper;
use File::Temp qw/ tempfile tempdir /;
use File::Find;
use File::Basename;
use mtr_results;
use mtr_report;
my %opts;
my %config;
my $help = "\n\nOptions for printing core dumps\n\n";
sub register_opt($$$) {
my ($name, $format, $msg)= @_;
my @names= split(/\|/, $name);
my $option_name= $names[0];
$option_name=~ s/-/_/;
$opts{$name. $format}= \$config{$option_name};
$help.= wrap(sprintf(" %-23s", join(', ', @names)), ' 'x25, "$msg\n");
}
# To preserve order we use array instead of hash
my @print_formats= (
short => {
description => "Failing stack trace",
codes => {}
},
medium => {
description => "All stack traces",
codes => {}
},
detailed => {
description => "All stack traces with debug context",
codes => {}
},
custom => {
description => "Custom debugger script for printing stack"
},
# 'no' must be last (check generated help)
no => {
description => "Skip stack trace printing"
}
);
# TODO: make class for each {method, get_code}
my @print_methods= (IS_WINDOWS) ? (cdb => { method => \&_cdb }) : (
gdb => {
method => \&_gdb,
get_code => \&_gdb_format,
},
dbx => {
method => \&_dbx
},
lldb => {
method => \&_lldb
},
# 'auto' must be last (check generated help)
auto => {
method => \&_auto
}
);
# But we also use hash
my %print_formats= @print_formats;
my %print_methods= @print_methods;
# and scalar
my $x= 0;
my $print_formats= join(', ', grep { ++$x % 2 } @print_formats);
$x= 0;
my $print_methods= join(', ', grep { ++$x % 2 } @print_methods);
# Fill 'short' and 'detailed' formats per each print_method
# that has interface for that
for my $f (keys %print_formats)
{
next unless exists $print_formats{$f}->{codes};
for my $m (keys %print_methods)
{
next unless exists $print_methods{$m}->{get_code};
# That calls f.ex. _gdb_format('short')
# and assigns { gdb => value-of-_gdb_format } into $print_formats{short}->{format}:
$print_formats{$f}->{codes}->{$m}= $print_methods{$m}->{get_code}->($f);
}
}
register_opt('print-core|C', ':s',
"Print core dump format: ". $print_formats. " (for not printing cores). ".
"Defaults to value of MTR_PRINT_CORE or 'medium'");
if (!IS_WINDOWS)
{
register_opt('print-method', '=s',
"Print core method: ". join(', ', $print_methods). " (try each method until success). ".
"Defaults to 'auto'");
}
sub options() { %opts }
sub help() { $help }
sub env_or_default($$) {
my ($default, $env)= @_;
if (exists $ENV{$env}) {
my $f= $ENV{$env};
$f= 'custom'
if $f =~ m/^custom:/;
return $ENV{$env}
if exists $print_formats{$f};
mtr_verbose("$env value ignored: $ENV{$env}");
}
return $default;
}
sub pre_setup() {
$config{print_core}= env_or_default('medium', 'MTR_PRINT_CORE')
if not defined $config{print_core};
$config{print_method}= (IS_WINDOWS) ? 'cdb' : 'auto'
if not defined $config{print_method};
# If the user has specified 'custom' we fill appropriate print_format
# and that will be used automatically
# Note: this can assign 'custom' to method 'auto'.
if ($config{print_core} =~ m/^custom:(.+)$/) {
$config{print_core}= 'custom';
$print_formats{'custom'}= {
$config{print_method} => $1
}
}
mtr_error "Wrong value for --print-core: $config{print_core}"
if not exists $print_formats{$config{print_core}};
mtr_error "Wrong value for --print-method: $config{print_method}"
if not exists $print_methods{$config{print_method}};
mtr_debug(Data::Dumper->Dump(
[\%config, \%print_formats, \%print_methods],
[qw(config print_formats print_methods)]));
}
my $hint_mysqld; # Last resort guess for executable path
# If path in core file is 79 chars we assume it's been truncated
# Looks like we can still find the full path using 'strings'
# If that doesn't work, use the hint (mysqld path) as last resort.
sub _verify_binpath {
my ($binary, $core_name)= @_;
my $binpath;
if (length $binary != 79) {
$binpath= $binary;
print "Core generated by '$binpath'\n";
} else {
# Last occurrence of path ending in /mysql*, cut from first /
if (`strings '$core_name' | grep "/mysql[^/. ]*\$" | tail -1` =~ /(\/.*)/) {
$binpath= $1;
print "Guessing that core was generated by '$binpath'\n";
} else {
return unless $hint_mysqld;
$binpath= $hint_mysqld;
print "Wild guess that core was generated by '$binpath'\n";
}
}
return $binpath;
}
# Returns GDB code according to specified format
# Note: this is like simple hash, separate interface was made
# in advance for implementing below TODO
# TODO: _gdb_format() and _gdb() should be separate class
# (like the other printing methods)
sub _gdb_format($) {
my ($format)= @_;
my %formats= (
short => "bt\n",
medium => "thread apply all bt\n",
detailed =>
"bt\n".
"set print sevenbit on\n".
"set print static-members off\n".
"set print frame-arguments all\n".
"thread apply all bt full\n".
"quit\n"
);
confess "Unknown format: ". $format
unless exists $formats{$format};
return $formats{$format};
}
sub _gdb {
my ($core_name, $code)= @_;
confess "Undefined format"
unless defined $code;
# Check that gdb exists
`gdb --version`;
if ($?) {
print "gdb not found, cannot get the stack trace\n";
return;
}
if (-f $core_name) {
mtr_verbose("Trying 'gdb' to get a backtrace from coredump $core_name");
} else {
print "\nCoredump $core_name does not exist, cannot run 'gdb'\n";
return;
}
# Find out name of binary that generated core
`gdb -c '$core_name' --batch 2>&1` =~
/Core was generated by `([^\s\'\`]+)/;
my $binary= $1 or return;
$binary= _verify_binpath ($binary, $core_name) or return;
# Create tempfile containing gdb commands
my ($tmp, $tmp_name) = tempfile();
print $tmp $code;
close $tmp or die "Error closing $tmp_name: $!";
# Run gdb
my $gdb_output=
`gdb '$binary' -c '$core_name' -x '$tmp_name' --batch 2>&1`;
unlink $tmp_name or die "Error removing $tmp_name: $!";
return if $? >> 8;
return unless $gdb_output;
resfile_print <<EOF . $gdb_output . "\n";
Output from gdb follows. The first stack trace is from the failing thread.
The following stack traces are from all threads (so the failing one is
duplicated).
--------------------------
EOF
return 1;
}
sub _dbx {
my ($core_name, $format)= @_;
print "\nTrying 'dbx' to get a backtrace\n";
return unless -f $core_name;
# Find out name of binary that generated core
`echo | dbx - '$core_name' 2>&1` =~
/Corefile specified executable: "([^"]+)"/;
my $binary= $1 or return;
$binary= _verify_binpath ($binary, $core_name) or return;
# Find all threads
my @thr_ids = `echo threads | dbx '$binary' '$core_name' 2>&1` =~ /t@\d+/g;
# Create tempfile containing dbx commands
my ($tmp, $tmp_name) = tempfile();
foreach my $thread (@thr_ids) {
print $tmp "where $thread\n";
}
print $tmp "exit\n";
close $tmp or die "Error closing $tmp_name: $!";
# Run dbx
my $dbx_output=
`cat '$tmp_name' | dbx '$binary' '$core_name' 2>&1`;
unlink $tmp_name or die "Error removing $tmp_name: $!";
return if $? >> 8;
return unless $dbx_output;
resfile_print <<EOF . $dbx_output . "\n";
Output from dbx follows. Stack trace is printed for all threads in order,
above this you should see info about which thread was the failing one.
----------------------------
EOF
return 1;
}
# Check that Debugging tools for Windows are installed
sub cdb_check {
`cdb -? 2>&1`;
if ($? >> 8)
{
print "Cannot find cdb. Please Install Debugging tools for Windows\n";
print "from http://www.microsoft.com/whdc/devtools/debugging/";
if($ENV{'ProgramW6432'})
{
print "install64bit.mspx (native x64 version)\n";
}
else
{
print "installx86.mspx\n";
}
}
}
sub _cdb {
my ($core_name, $format)= @_;
print "\nTrying 'cdb' to get a backtrace\n";
return unless -f $core_name;
# Try to set environment for debugging tools for Windows
if ($ENV{'PATH'} !~ /Debugging Tools/)
{
if ($ENV{'ProgramW6432'})
{
# On x64 computer
$ENV{'PATH'}.= ";".$ENV{'ProgramW6432'}."\\Debugging Tools For Windows (x64)";
}
else
{
# On x86 computer. Newest versions of Debugging tools are installed in the
# directory with (x86) suffix, older versions did not have this suffix.
$ENV{'PATH'}.= ";".$ENV{'ProgramFiles'}."\\Debugging Tools For Windows (x86)";
$ENV{'PATH'}.= ";".$ENV{'ProgramFiles'}."\\Debugging Tools For Windows";
}
}
# Read module list, find out the name of executable and
# build symbol path (required by cdb if executable was built on
# different machine)
my $tmp_name= $core_name.".cdb_lmv";
`cdb -z $core_name -c \"lmv;q\" > $tmp_name 2>&1`;
if ($? >> 8)
{
unlink($tmp_name);
# check if cdb is installed and complain if not
cdb_check();
return;
}
open(temp,"< $tmp_name");
my %dirhash=();
while(<temp>)
{
if($_ =~ /Image path\: (.*)/)
{
if (rindex($1,'\\') != -1)
{
my $dir= substr($1, 0, rindex($1,'\\'));
$dirhash{$dir}++;
}
}
}
close(temp);
unlink($tmp_name);
my $image_path= join(";", (keys %dirhash),".");
# For better callstacks, setup _NT_SYMBOL_PATH to include
# OS symbols. Note : Dowloading symbols for the first time
# can take some minutes
if (!$ENV{'_NT_SYMBOL_PATH'})
{
my $windir= $ENV{'windir'};
my $symbol_cache= substr($windir ,0, index($windir,'\\'))."\\cdb_symbols";
print "OS debug symbols will be downloaded and stored in $symbol_cache.\n";
print "You can control the location of symbol cache with _NT_SYMBOL_PATH\n";
print "environment variable. Please refer to Microsoft KB article\n";
print "http://support.microsoft.com/kb/311503 for details about _NT_SYMBOL_PATH\n";
print "-------------------------------------------------------------------------\n";
$ENV{'_NT_SYMBOL_PATH'}.=
"srv*".$symbol_cache."*http://msdl.microsoft.com/download/symbols";
}
my $symbol_path= $image_path.";".$ENV{'_NT_SYMBOL_PATH'};
# Run cdb. Use "analyze" extension to print crashing thread stacktrace
# and "uniqstack" to print other threads
my $cdb_cmd = "!sym prompts off; !analyze -v; .ecxr; !for_each_frame dv /t;!uniqstack -p;q";
my $cdb_output=
`cdb -c "$cdb_cmd" -z $core_name -i "$image_path" -y "$symbol_path" -t 0 -lines 2>&1`;
return if $? >> 8;
return unless $cdb_output;
# Remove comments (lines starting with *), stack pointer and frame
# pointer adresses and offsets to function to make output better readable
$cdb_output=~ s/^\*.*\n//gm;
$cdb_output=~ s/^([\:0-9a-fA-F\`]+ )+//gm;
$cdb_output=~ s/^ChildEBP RetAddr//gm;
$cdb_output=~ s/^Child\-SP RetAddr Call Site//gm;
$cdb_output=~ s/\+0x([0-9a-fA-F]+)//gm;
resfile_print <<EOF . $cdb_output . "\n";
Output from cdb follows. Faulting thread is printed twice,with and without function parameters
Search for STACK_TEXT to see the stack trace of
the faulting thread. Callstacks of other threads are printed after it.
EOF
return 1;
}
sub _lldb
{
my ($core_name)= @_;
print "\nTrying 'lldb' to get a backtrace from coredump $core_name\n";
# Create tempfile containing lldb commands
my ($tmp, $tmp_name)= tempfile();
print $tmp
"bt\n",
"thread backtrace all\n",
"quit\n";
close $tmp or die "Error closing $tmp_name: $!";
my $lldb_output= `lldb -c '$core_name' -s '$tmp_name' 2>&1`;
unlink $tmp_name or die "Error removing $tmp_name: $!";
if ($? == 127)
{
print "lldb not found, cannot get the stack trace\n";
return;
}
return if $?;
return unless $lldb_output;
resfile_print <<EOF . $lldb_output . "\n";
Output from lldb follows. The first stack trace is from the failing thread.
The following stack traces are from all threads (so the failing one is
duplicated).
--------------------------
EOF
return 1;
}
sub _auto
{
my ($core_name, $code, $rest)= @_;
# We use ordered array @print_methods and omit auto itself
my @valid_methods= @print_methods[0 .. $#print_methods - 2];
my $x= 0;
my @methods= grep { ++$x % 2} @valid_methods;
my $f= $config{print_core};
foreach my $m (@methods)
{
my $debugger= $print_methods{$m};
confess "Broken @print_methods"
if $debugger->{method} == \&_auto;
# If we didn't find format for 'auto' (that is only possible for 'custom')
# we get format for specific debugger
if (not defined $code && defined $print_formats{$f} and
exists $print_formats{$f}->{codes}->{$m})
{
$code= $print_formats{$f}->{codes}->{$m};
}
mtr_verbose2("Trying to print with method ${m}:${f}");
if ($debugger->{method}->($core_name, $code)) {
return;
}
}
}
sub show {
my ($core_name, $exe_mysqld, $parallel)= @_;
if ($config{print_core} ne 'no') {
my $f= $config{print_core};
my $m= $config{print_method};
my $code= undef;
if (exists $print_formats{$f}->{codes} and
exists $print_formats{$f}->{codes}->{$m}) {
$code= $print_formats{$f}->{codes}->{$m};
}
mtr_verbose2("Printing core with method ${m}:${f}");
mtr_debug("code: ${code}");
$print_methods{$m}->{method}->($core_name, $code);
}
return;
}
sub core_wanted($$$$$) {
my ($num_saved_cores, $opt_max_save_core, $compress,
$exe_mysqld, $opt_parallel)= @_;
my $core_file= $File::Find::name;
my $core_name= basename($core_file);
# Name beginning with core, not ending in .gz
if (($core_name =~ /^core/ and $core_name !~ /\.gz$/)
or (IS_WINDOWS and $core_name =~ /\.dmp$/))
{
# Ending with .dmp
mtr_report(" - found '$core_name'",
"($$num_saved_cores/$opt_max_save_core)");
show($core_file, $exe_mysqld, $opt_parallel);
# Limit number of core files saved
if ($$num_saved_cores >= $opt_max_save_core)
{
mtr_report(" - deleting it, already saved",
"$opt_max_save_core");
unlink("$core_file");
}
else
{
main::mtr_compress_file($core_file) if $compress;
++$$num_saved_cores;
}
}
}
1;