Adding a userspace application crash handling system to autotest

Commit Message

Lucas Meneghel Rodrigues Sept. 8, 2009, 1:53 p.m. UTC

This patch adds a system to watch user space segmentation
faults, writing core dumps and some degree of core dump
analysis report. We believe that such a system will be
beneficial for autotest as a whole, since the ability to
get core dumps and dump analysis for each app crashing
during an autotest execution can help test engineers with
richer debugging information.

The system is comprised by 2 parts:

 * Modifications on test code that enable core dumps
generation, register a core handler script in the kernel
and check by generated core files at the end of each
test.

 * A core handler script that is going to write the
core on each test debug dir in a convenient way, with
a report that currently is comprised by the process that
died and a gdb stacktrace of the process. As the system
gets in shape, we could add more scripts that can do
fancier stuff (such as handlers that use frysk to get
more info such as memory maps, provided that we have
frysk installed in the machine).

This is the proof of concept of the system. I am sending it
to the mailing list on this early stage so I can get
feedback on the feature. The system passes my basic
tests:

 * Run a simple long test, such as the kvm test, and
then crash an application while the test is running. I
get reports generated on test.debugdir

 * Run a slightly more complex control file, with 3 parallel
bonnie instances at once and crash an application while the
test is running. I get reports generated on all
test.debugdirs.

3rd try:
 * Explicitely enable core dumps using the resource module
 * Fixed a bug on the crash detection code, and factored
   it into a utility function.

I believe we are good to go now.

Signed-off-by: Lucas Meneghel Rodrigues <[e-mail]>
---
 client/common_lib/test.py     |   66 +++++++++++++-
 client/tools/crash_handler.py |  202 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 266 insertions(+), 2 deletions(-)
 create mode 100755 client/tools/crash_handler.py

Comments

Lucas Meneghel Rodrigues Sept. 14, 2009, 4:40 a.m. UTC | #1

Hi John, do you think the code looks good enough for inclusion?

On Tue, Sep 8, 2009 at 10:53 AM, Lucas Meneghel Rodrigues
<[e-mail]> wrote:
> This patch adds a system to watch user space segmentation
> faults, writing core dumps and some degree of core dump
> analysis report. We believe that such a system will be
> beneficial for autotest as a whole, since the ability to
> get core dumps and dump analysis for each app crashing
> during an autotest execution can help test engineers with
> richer debugging information.
>
> The system is comprised by 2 parts:
>
>  * Modifications on test code that enable core dumps
> generation, register a core handler script in the kernel
> and check by generated core files at the end of each
> test.
>
>  * A core handler script that is going to write the
> core on each test debug dir in a convenient way, with
> a report that currently is comprised by the process that
> died and a gdb stacktrace of the process. As the system
> gets in shape, we could add more scripts that can do
> fancier stuff (such as handlers that use frysk to get
> more info such as memory maps, provided that we have
> frysk installed in the machine).
>
> This is the proof of concept of the system. I am sending it
> to the mailing list on this early stage so I can get
> feedback on the feature. The system passes my basic
> tests:
>
>  * Run a simple long test, such as the kvm test, and
> then crash an application while the test is running. I
> get reports generated on test.debugdir
>
>  * Run a slightly more complex control file, with 3 parallel
> bonnie instances at once and crash an application while the
> test is running. I get reports generated on all
> test.debugdirs.
>
> 3rd try:
>  * Explicitely enable core dumps using the resource module
>  * Fixed a bug on the crash detection code, and factored
>   it into a utility function.
>
> I believe we are good to go now.
>
> Signed-off-by: Lucas Meneghel Rodrigues <[e-mail]>
> ---
>  client/common_lib/test.py     |   66 +++++++++++++-
>  client/tools/crash_handler.py |  202 +++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 266 insertions(+), 2 deletions(-)
>  create mode 100755 client/tools/crash_handler.py
>
> diff --git a/client/common_lib/test.py b/client/common_lib/test.py
> index 362c960..65b78a3 100644
> --- a/client/common_lib/test.py
> +++ b/client/common_lib/test.py
> @@ -17,7 +17,7 @@
>  #       tmpdir          eg. tmp/<tempname>_<testname.tag>
>
>  import fcntl, os, re, sys, shutil, tarfile, tempfile, time, traceback
> -import warnings, logging
> +import warnings, logging, glob, resource
>
>  from autotest_lib.client.common_lib import error
>  from autotest_lib.client.bin import utils
> @@ -31,7 +31,6 @@ class base_test:
>         self.job = job
>         self.pkgmgr = job.pkgmgr
>         self.autodir = job.autodir
> -
>         self.outputdir = outputdir
>         self.tagged_testname = os.path.basename(self.outputdir)
>         self.resultsdir = os.path.join(self.outputdir, 'results')
> @@ -40,6 +39,7 @@ class base_test:
>         os.mkdir(self.profdir)
>         self.debugdir = os.path.join(self.outputdir, 'debug')
>         os.mkdir(self.debugdir)
> +        self.configure_crash_handler()
>         self.bindir = bindir
>         if hasattr(job, 'libdir'):
>             self.libdir = job.libdir
> @@ -54,6 +54,66 @@ class base_test:
>         self.after_iteration_hooks = []
>
>
> +    def configure_crash_handler(self):
> +        """
> +        Configure the crash handler by:
> +         * Setting up core size to unlimited
> +         * Putting an appropriate crash handler on /proc/sys/kernel/core_pattern
> +         * Create files that the crash handler will use to figure which tests
> +           are active at a given moment
> +
> +        The crash handler will pick up the core file and write it to
> +        self.debugdir, and perform analysis on it to generate a report. The
> +        program also outputs some results to syslog.
> +
> +        If multiple tests are running, an attempt to verify if we still have
> +        the old PID on the system process table to determine whether it is a
> +        parent of the current test execution. If we can't determine it, the
> +        core file and the report file will be copied to all test debug dirs.
> +        """
> +        self.pattern_file = '/proc/sys/kernel/core_pattern'
> +        try:
> +            # Enable core dumps
> +            resource.setrlimit(resource.RLIMIT_CORE, (-1, -1))
> +            # Trying to backup core pattern and register our script
> +            self.core_pattern_backup = open(self.pattern_file, 'r').read()
> +            pattern_file = open(self.pattern_file, 'w')
> +            tools_dir = os.path.join(self.autodir, 'tools')
> +            crash_handler_path = os.path.join(tools_dir, 'crash_handler.py')
> +            pattern_file.write('|' + crash_handler_path + ' %p %t %u %s %h %e')
> +            # Writing the files that the crash handler is going to use
> +            self.debugdir_tmp_file = ('/tmp/autotest_results_dir.%s' %
> +                                      os.getpid())
> +            utils.open_write_close(self.debugdir_tmp_file, self.debugdir + "\n")
> +        except Exception, e:
> +            self.crash_handling_enabled = False
> +            logging.error('Crash handling system disabled: %s' % e)
> +        else:
> +            self.crash_handling_enabled = True
> +            logging.debug('Crash handling system enabled.')
> +
> +
> +    def crash_handler_report(self):
> +        """
> +        If core dumps are found on the debugdir after the execution of the
> +        test, let the user know.
> +        """
> +        if self.crash_handling_enabled:
> +            core_dirs = glob.glob('%s/crash.*' % self.debugdir)
> +            if core_dirs:
> +                logging.warning('Programs crashed during test execution:')
> +                for dir in core_dirs:
> +                    logging.warning('Please verify %s for more info', dir)
> +            # Remove the debugdir info file
> +            os.unlink(self.debugdir_tmp_file)
> +            # Restore the core pattern backup
> +            try:
> +                utils.open_write_close(self.pattern_file,
> +                                       self.core_pattern_backup)
> +            except EnvironmentError:
> +                pass
> +
> +
>     def assert_(self, expr, msg='Assertion failed.'):
>         if not expr:
>             raise error.TestError(msg)
> @@ -377,6 +437,7 @@ class base_test:
>                         traceback.print_exc()
>                         print 'Now raising the earlier %s error' % exc_info[0]
>                 finally:
> +                    self.crash_handler_report()
>                     self.job.logging.restore()
>                     try:
>                         raise exc_info[0], exc_info[1], exc_info[2]
> @@ -389,6 +450,7 @@ class base_test:
>                     if run_cleanup:
>                         _cherry_pick_call(self.cleanup, *args, **dargs)
>                 finally:
> +                    self.crash_handler_report()
>                     self.job.logging.restore()
>         except error.AutotestError:
>             if self.network_destabilizing:
> diff --git a/client/tools/crash_handler.py b/client/tools/crash_handler.py
> new file mode 100755
> index 0000000..e281eb5
> --- /dev/null
> +++ b/client/tools/crash_handler.py
> @@ -0,0 +1,202 @@
> +#!/usr/bin/python
> +"""
> +Simple crash handling application for autotest
> +
> +@copyright Red Hat Inc 2009
> +@author Lucas Meneghel Rodrigues <[e-mail]>
> +"""
> +import sys, os, commands, glob, tempfile, shutil, syslog
> +
> +
> +def get_parent_pid(pid):
> +    """
> +    Returns the parent PID for a given PID, converted to an integer.
> +
> +    @param pid: Process ID.
> +    """
> +    try:
> +        stat_file_contents = open('/proc/%s/stat' % pid, 'r').readline()
> +        ppid = int(stat_file_contents.split(" ")[3])
> +    except:
> +        # It is not possible to determine the parent because the process
> +        # already left the process table.
> +        ppid = 1
> +
> +    return ppid
> +
> +
> +def pid_descends_from(pid_a, pid_b):
> +    """
> +    Check whether pid_a descends from pid_b.
> +
> +    @param pid_a: Process ID.
> +    @param pid_b: Process ID.
> +    """
> +    pid_a = int(pid_a)
> +    pid_b = int(pid_b)
> +    current_pid = pid_a
> +    while current_pid > 1:
> +        if current_pid == pid_b:
> +            syslog.syslog(syslog.LOG_INFO,
> +                          "PID %s descends from PID %s!" % (pid_a, pid_b))
> +            return True
> +        else:
> +            current_pid = get_parent_pid(current_pid)
> +    syslog.syslog(syslog.LOG_INFO,
> +                  "PID %s does not descend from PID %s" % (pid_a, pid_b))
> +    return False
> +
> +
> +def write_to_file(file_path, contents):
> +    """
> +    Write contents to a given file path specified. If not specified, the file
> +    will be created.
> +
> +    @param file_path: Path to a given file.
> +    @param contents: File contents.
> +    """
> +    file_object = open(file_path, 'w')
> +    file_object.write(contents)
> +    file_object.close()
> +
> +
> +def get_results_dir_list(pid, core_dir_basename):
> +    """
> +    Get all valid output directories for the core file and the report. It works
> +    by inspecting files created by each test on /tmp and verifying if the
> +    PID of the process that crashed is a child or grandchild of the autotest
> +    test process. If it can't find any relationship (maybe a daemon that died
> +    during a test execution), it will write the core file to the debug dirs
> +    of all tests currently being executed. If there are no active autotest
> +    tests at a particular moment, it will return a list with ['/tmp'].
> +
> +    @param pid: PID for the process that generated the core
> +    @param core_dir_basename: Basename for the directory that will hold both
> +            the core dump and the crash report.
> +    """
> +    # Get all active test debugdir path files present
> +    debugdir_files = glob.glob("/tmp/autotest_results_dir.*")
> +    if debugdir_files:
> +        pid_dir_dict = {}
> +        for debugdir_file in debugdir_files:
> +            a_pid = debugdir_file.split('.')[-1]
> +            results_dir = open(debugdir_file, 'r').read().strip()
> +            pid_dir_dict[a_pid] = os.path.join(results_dir, core_dir_basename)
> +
> +        results_dir_list = []
> +        found_relation = False
> +        for a_pid, a_path in pid_dir_dict.iteritems():
> +            if pid_descends_from(pid, a_pid):
> +                results_dir_list.append(a_path)
> +                found_relation = True
> +
> +        # If we could not find any relations between the pids in the list with
> +        # the process that crashed, we can't tell for sure which test spawned
> +        # the process (maybe it is a daemon and started even before autotest
> +        # started), so we will have to output the core file to all active test
> +        # directories.
> +        if not found_relation:
> +            return pid_dir_dict.values()
> +        else:
> +            return results_dir_list
> +
> +    else:
> +        path_inactive_autotest = os.path.join('/tmp', core_dir_basename)
> +        return [path_inactive_autotest]
> +
> +
> +def get_info_from_core(path):
> +    """
> +    Reads a core file and extracts a dictionary with useful core information.
> +    Right now, the only information extracted is the full executable name.
> +
> +    @param path: Path to core file.
> +    """
> +    # Here we are getting the executable full path in a very inelegant way :(
> +    # Since the 'right' solution for it is to make a library to get information
> +    # from core dump files, properly written, I'll leave this as it is for now.
> +    full_exe_path = commands.getoutput('strings %s | grep "_="' %
> +                                       path).strip("_=")
> +    if full_exe_path.startswith("./"):
> +        pwd = commands.getoutput('strings %s | grep "^PWD="' %
> +                                 path).strip("PWD=")
> +        full_exe_path = os.path.join(pwd, full_exe_path.strip("./"))
> +
> +    return {'core_file': path, 'full_exe_path': full_exe_path}
> +
> +
> +if __name__ == "__main__":
> +    syslog.openlog('AutotestCrashHandler', 0, syslog.LOG_DAEMON)
> +    (crashed_pid, time, uid, signal, hostname, exe) = sys.argv[1:]
> +    core_name = 'core'
> +    report_name = 'report'
> +    core_dir_name = 'crash.%s.%s' % (exe, crashed_pid)
> +    core_tmp_dir = tempfile.mkdtemp(prefix='core_', dir='/tmp')
> +    core_tmp_path = os.path.join(core_tmp_dir, core_name)
> +    gdb_command_path = os.path.join(core_tmp_dir, 'gdb_command')
> +
> +    try:
> +        # Get the filtered results dir list
> +        current_results_dir_list = get_results_dir_list(crashed_pid,
> +                                                        core_dir_name)
> +
> +        # Write the core file to the appropriate directory
> +        # (we are piping it to this script)
> +        core_file = sys.stdin.read()
> +        write_to_file(core_tmp_path, core_file)
> +
> +        # Write a command file for GDB
> +        gdb_command = 'bt full\n'
> +        write_to_file(gdb_command_path, gdb_command)
> +
> +        # Get full command path
> +        exe_path = get_info_from_core(core_tmp_path)['full_exe_path']
> +
> +        # Take a backtrace from the running program
> +        gdb_cmd = 'gdb -e %s -c %s -x %s -n -batch -quiet' % (exe_path,
> +                                                              core_tmp_path,
> +                                                              gdb_command_path)
> +        backtrace = commands.getoutput(gdb_cmd)
> +        # Sanitize output before passing it to the report
> +        backtrace = backtrace.decode('utf-8', 'ignore')
> +
> +        # Composing the format_dict
> +        format_dict = {}
> +        format_dict['program'] = exe_path
> +        format_dict['pid'] = crashed_pid
> +        format_dict['signal'] = signal
> +        format_dict['hostname'] = hostname
> +        format_dict['time'] = time
> +        format_dict['backtrace'] = backtrace
> +
> +        report = """Autotest crash report
> +
> +Program: %(program)s
> +PID: %(pid)s
> +Signal: %(signal)s
> +Hostname: %(hostname)s
> +Time of the crash: %(time)s
> +Program backtrace:
> +%(backtrace)s
> +""" % format_dict
> +
> +        syslog.syslog(syslog.LOG_INFO,
> +                      "Application %s, PID %s crashed" %
> +                      (exe_path, crashed_pid))
> +
> +        # Now, for all results dir, let's create the directory if it doesn't
> +        # exist, and write the core file and the report to it.
> +        syslog.syslog(syslog.LOG_INFO,
> +                      "Writing core files and reports to %s" %
> +                      current_results_dir_list)
> +        for result_dir in current_results_dir_list:
> +            if not os.path.isdir(result_dir):
> +                os.makedirs(result_dir)
> +            core_path = os.path.join(result_dir, 'core')
> +            write_to_file(core_path, core_file)
> +            report_path = os.path.join(result_dir, 'report')
> +            write_to_file(report_path, report)
> +
> +    finally:
> +        # Cleanup temporary directories
> +        shutil.rmtree(core_tmp_dir)
> --
> 1.6.2.5
>
> _______________________________________________
> Autotest mailing list
> [e-mail]
> http://test.kernel.org/cgi-bin/mailman/listinfo/autotest
>

John Admanski Sept. 14, 2009, 2:39 p.m. UTC | #2

Sorry, I haven't had time to take a look yet. Been busy. :(

I'll try and get in a review some time today.

-- John

On Sun, Sep 13, 2009 at 9:40 PM, Lucas Meneghel Rodrigues
<[e-mail]> wrote:
> Hi John, do you think the code looks good enough for inclusion?
>
> On Tue, Sep 8, 2009 at 10:53 AM, Lucas Meneghel Rodrigues
> <[e-mail]> wrote:
>> This patch adds a system to watch user space segmentation
>> faults, writing core dumps and some degree of core dump
>> analysis report. We believe that such a system will be
>> beneficial for autotest as a whole, since the ability to
>> get core dumps and dump analysis for each app crashing
>> during an autotest execution can help test engineers with
>> richer debugging information.
>>
>> The system is comprised by 2 parts:
>>
>>  * Modifications on test code that enable core dumps
>> generation, register a core handler script in the kernel
>> and check by generated core files at the end of each
>> test.
>>
>>  * A core handler script that is going to write the
>> core on each test debug dir in a convenient way, with
>> a report that currently is comprised by the process that
>> died and a gdb stacktrace of the process. As the system
>> gets in shape, we could add more scripts that can do
>> fancier stuff (such as handlers that use frysk to get
>> more info such as memory maps, provided that we have
>> frysk installed in the machine).
>>
>> This is the proof of concept of the system. I am sending it
>> to the mailing list on this early stage so I can get
>> feedback on the feature. The system passes my basic
>> tests:
>>
>>  * Run a simple long test, such as the kvm test, and
>> then crash an application while the test is running. I
>> get reports generated on test.debugdir
>>
>>  * Run a slightly more complex control file, with 3 parallel
>> bonnie instances at once and crash an application while the
>> test is running. I get reports generated on all
>> test.debugdirs.
>>
>> 3rd try:
>>  * Explicitely enable core dumps using the resource module
>>  * Fixed a bug on the crash detection code, and factored
>>   it into a utility function.
>>
>> I believe we are good to go now.
>>
>> Signed-off-by: Lucas Meneghel Rodrigues <[e-mail]>
>> ---
>>  client/common_lib/test.py     |   66 +++++++++++++-
>>  client/tools/crash_handler.py |  202 +++++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 266 insertions(+), 2 deletions(-)
>>  create mode 100755 client/tools/crash_handler.py
>>
>> diff --git a/client/common_lib/test.py b/client/common_lib/test.py
>> index 362c960..65b78a3 100644
>> --- a/client/common_lib/test.py
>> +++ b/client/common_lib/test.py
>> @@ -17,7 +17,7 @@
>>  #       tmpdir          eg. tmp/<tempname>_<testname.tag>
>>
>>  import fcntl, os, re, sys, shutil, tarfile, tempfile, time, traceback
>> -import warnings, logging
>> +import warnings, logging, glob, resource
>>
>>  from autotest_lib.client.common_lib import error
>>  from autotest_lib.client.bin import utils
>> @@ -31,7 +31,6 @@ class base_test:
>>         self.job = job
>>         self.pkgmgr = job.pkgmgr
>>         self.autodir = job.autodir
>> -
>>         self.outputdir = outputdir
>>         self.tagged_testname = os.path.basename(self.outputdir)
>>         self.resultsdir = os.path.join(self.outputdir, 'results')
>> @@ -40,6 +39,7 @@ class base_test:
>>         os.mkdir(self.profdir)
>>         self.debugdir = os.path.join(self.outputdir, 'debug')
>>         os.mkdir(self.debugdir)
>> +        self.configure_crash_handler()
>>         self.bindir = bindir
>>         if hasattr(job, 'libdir'):
>>             self.libdir = job.libdir
>> @@ -54,6 +54,66 @@ class base_test:
>>         self.after_iteration_hooks = []
>>
>>
>> +    def configure_crash_handler(self):
>> +        """
>> +        Configure the crash handler by:
>> +         * Setting up core size to unlimited
>> +         * Putting an appropriate crash handler on /proc/sys/kernel/core_pattern
>> +         * Create files that the crash handler will use to figure which tests
>> +           are active at a given moment
>> +
>> +        The crash handler will pick up the core file and write it to
>> +        self.debugdir, and perform analysis on it to generate a report. The
>> +        program also outputs some results to syslog.
>> +
>> +        If multiple tests are running, an attempt to verify if we still have
>> +        the old PID on the system process table to determine whether it is a
>> +        parent of the current test execution. If we can't determine it, the
>> +        core file and the report file will be copied to all test debug dirs.
>> +        """
>> +        self.pattern_file = '/proc/sys/kernel/core_pattern'
>> +        try:
>> +            # Enable core dumps
>> +            resource.setrlimit(resource.RLIMIT_CORE, (-1, -1))
>> +            # Trying to backup core pattern and register our script
>> +            self.core_pattern_backup = open(self.pattern_file, 'r').read()
>> +            pattern_file = open(self.pattern_file, 'w')
>> +            tools_dir = os.path.join(self.autodir, 'tools')
>> +            crash_handler_path = os.path.join(tools_dir, 'crash_handler.py')
>> +            pattern_file.write('|' + crash_handler_path + ' %p %t %u %s %h %e')
>> +            # Writing the files that the crash handler is going to use
>> +            self.debugdir_tmp_file = ('/tmp/autotest_results_dir.%s' %
>> +                                      os.getpid())
>> +            utils.open_write_close(self.debugdir_tmp_file, self.debugdir + "\n")
>> +        except Exception, e:
>> +            self.crash_handling_enabled = False
>> +            logging.error('Crash handling system disabled: %s' % e)
>> +        else:
>> +            self.crash_handling_enabled = True
>> +            logging.debug('Crash handling system enabled.')
>> +
>> +
>> +    def crash_handler_report(self):
>> +        """
>> +        If core dumps are found on the debugdir after the execution of the
>> +        test, let the user know.
>> +        """
>> +        if self.crash_handling_enabled:
>> +            core_dirs = glob.glob('%s/crash.*' % self.debugdir)
>> +            if core_dirs:
>> +                logging.warning('Programs crashed during test execution:')
>> +                for dir in core_dirs:
>> +                    logging.warning('Please verify %s for more info', dir)
>> +            # Remove the debugdir info file
>> +            os.unlink(self.debugdir_tmp_file)
>> +            # Restore the core pattern backup
>> +            try:
>> +                utils.open_write_close(self.pattern_file,
>> +                                       self.core_pattern_backup)
>> +            except EnvironmentError:
>> +                pass
>> +
>> +
>>     def assert_(self, expr, msg='Assertion failed.'):
>>         if not expr:
>>             raise error.TestError(msg)
>> @@ -377,6 +437,7 @@ class base_test:
>>                         traceback.print_exc()
>>                         print 'Now raising the earlier %s error' % exc_info[0]
>>                 finally:
>> +                    self.crash_handler_report()
>>                     self.job.logging.restore()
>>                     try:
>>                         raise exc_info[0], exc_info[1], exc_info[2]
>> @@ -389,6 +450,7 @@ class base_test:
>>                     if run_cleanup:
>>                         _cherry_pick_call(self.cleanup, *args, **dargs)
>>                 finally:
>> +                    self.crash_handler_report()
>>                     self.job.logging.restore()
>>         except error.AutotestError:
>>             if self.network_destabilizing:
>> diff --git a/client/tools/crash_handler.py b/client/tools/crash_handler.py
>> new file mode 100755
>> index 0000000..e281eb5
>> --- /dev/null
>> +++ b/client/tools/crash_handler.py
>> @@ -0,0 +1,202 @@
>> +#!/usr/bin/python
>> +"""
>> +Simple crash handling application for autotest
>> +
>> +@copyright Red Hat Inc 2009
>> +@author Lucas Meneghel Rodrigues <[e-mail]>
>> +"""
>> +import sys, os, commands, glob, tempfile, shutil, syslog
>> +
>> +
>> +def get_parent_pid(pid):
>> +    """
>> +    Returns the parent PID for a given PID, converted to an integer.
>> +
>> +    @param pid: Process ID.
>> +    """
>> +    try:
>> +        stat_file_contents = open('/proc/%s/stat' % pid, 'r').readline()
>> +        ppid = int(stat_file_contents.split(" ")[3])
>> +    except:
>> +        # It is not possible to determine the parent because the process
>> +        # already left the process table.
>> +        ppid = 1
>> +
>> +    return ppid
>> +
>> +
>> +def pid_descends_from(pid_a, pid_b):
>> +    """
>> +    Check whether pid_a descends from pid_b.
>> +
>> +    @param pid_a: Process ID.
>> +    @param pid_b: Process ID.
>> +    """
>> +    pid_a = int(pid_a)
>> +    pid_b = int(pid_b)
>> +    current_pid = pid_a
>> +    while current_pid > 1:
>> +        if current_pid == pid_b:
>> +            syslog.syslog(syslog.LOG_INFO,
>> +                          "PID %s descends from PID %s!" % (pid_a, pid_b))
>> +            return True
>> +        else:
>> +            current_pid = get_parent_pid(current_pid)
>> +    syslog.syslog(syslog.LOG_INFO,
>> +                  "PID %s does not descend from PID %s" % (pid_a, pid_b))
>> +    return False
>> +
>> +
>> +def write_to_file(file_path, contents):
>> +    """
>> +    Write contents to a given file path specified. If not specified, the file
>> +    will be created.
>> +
>> +    @param file_path: Path to a given file.
>> +    @param contents: File contents.
>> +    """
>> +    file_object = open(file_path, 'w')
>> +    file_object.write(contents)
>> +    file_object.close()
>> +
>> +
>> +def get_results_dir_list(pid, core_dir_basename):
>> +    """
>> +    Get all valid output directories for the core file and the report. It works
>> +    by inspecting files created by each test on /tmp and verifying if the
>> +    PID of the process that crashed is a child or grandchild of the autotest
>> +    test process. If it can't find any relationship (maybe a daemon that died
>> +    during a test execution), it will write the core file to the debug dirs
>> +    of all tests currently being executed. If there are no active autotest
>> +    tests at a particular moment, it will return a list with ['/tmp'].
>> +
>> +    @param pid: PID for the process that generated the core
>> +    @param core_dir_basename: Basename for the directory that will hold both
>> +            the core dump and the crash report.
>> +    """
>> +    # Get all active test debugdir path files present
>> +    debugdir_files = glob.glob("/tmp/autotest_results_dir.*")
>> +    if debugdir_files:
>> +        pid_dir_dict = {}
>> +        for debugdir_file in debugdir_files:
>> +            a_pid = debugdir_file.split('.')[-1]
>> +            results_dir = open(debugdir_file, 'r').read().strip()
>> +            pid_dir_dict[a_pid] = os.path.join(results_dir, core_dir_basename)
>> +
>> +        results_dir_list = []
>> +        found_relation = False
>> +        for a_pid, a_path in pid_dir_dict.iteritems():
>> +            if pid_descends_from(pid, a_pid):
>> +                results_dir_list.append(a_path)
>> +                found_relation = True
>> +
>> +        # If we could not find any relations between the pids in the list with
>> +        # the process that crashed, we can't tell for sure which test spawned
>> +        # the process (maybe it is a daemon and started even before autotest
>> +        # started), so we will have to output the core file to all active test
>> +        # directories.
>> +        if not found_relation:
>> +            return pid_dir_dict.values()
>> +        else:
>> +            return results_dir_list
>> +
>> +    else:
>> +        path_inactive_autotest = os.path.join('/tmp', core_dir_basename)
>> +        return [path_inactive_autotest]
>> +
>> +
>> +def get_info_from_core(path):
>> +    """
>> +    Reads a core file and extracts a dictionary with useful core information.
>> +    Right now, the only information extracted is the full executable name.
>> +
>> +    @param path: Path to core file.
>> +    """
>> +    # Here we are getting the executable full path in a very inelegant way :(
>> +    # Since the 'right' solution for it is to make a library to get information
>> +    # from core dump files, properly written, I'll leave this as it is for now.
>> +    full_exe_path = commands.getoutput('strings %s | grep "_="' %
>> +                                       path).strip("_=")
>> +    if full_exe_path.startswith("./"):
>> +        pwd = commands.getoutput('strings %s | grep "^PWD="' %
>> +                                 path).strip("PWD=")
>> +        full_exe_path = os.path.join(pwd, full_exe_path.strip("./"))
>> +
>> +    return {'core_file': path, 'full_exe_path': full_exe_path}
>> +
>> +
>> +if __name__ == "__main__":
>> +    syslog.openlog('AutotestCrashHandler', 0, syslog.LOG_DAEMON)
>> +    (crashed_pid, time, uid, signal, hostname, exe) = sys.argv[1:]
>> +    core_name = 'core'
>> +    report_name = 'report'
>> +    core_dir_name = 'crash.%s.%s' % (exe, crashed_pid)
>> +    core_tmp_dir = tempfile.mkdtemp(prefix='core_', dir='/tmp')
>> +    core_tmp_path = os.path.join(core_tmp_dir, core_name)
>> +    gdb_command_path = os.path.join(core_tmp_dir, 'gdb_command')
>> +
>> +    try:
>> +        # Get the filtered results dir list
>> +        current_results_dir_list = get_results_dir_list(crashed_pid,
>> +                                                        core_dir_name)
>> +
>> +        # Write the core file to the appropriate directory
>> +        # (we are piping it to this script)
>> +        core_file = sys.stdin.read()
>> +        write_to_file(core_tmp_path, core_file)
>> +
>> +        # Write a command file for GDB
>> +        gdb_command = 'bt full\n'
>> +        write_to_file(gdb_command_path, gdb_command)
>> +
>> +        # Get full command path
>> +        exe_path = get_info_from_core(core_tmp_path)['full_exe_path']
>> +
>> +        # Take a backtrace from the running program
>> +        gdb_cmd = 'gdb -e %s -c %s -x %s -n -batch -quiet' % (exe_path,
>> +                                                              core_tmp_path,
>> +                                                              gdb_command_path)
>> +        backtrace = commands.getoutput(gdb_cmd)
>> +        # Sanitize output before passing it to the report
>> +        backtrace = backtrace.decode('utf-8', 'ignore')
>> +
>> +        # Composing the format_dict
>> +        format_dict = {}
>> +        format_dict['program'] = exe_path
>> +        format_dict['pid'] = crashed_pid
>> +        format_dict['signal'] = signal
>> +        format_dict['hostname'] = hostname
>> +        format_dict['time'] = time
>> +        format_dict['backtrace'] = backtrace
>> +
>> +        report = """Autotest crash report
>> +
>> +Program: %(program)s
>> +PID: %(pid)s
>> +Signal: %(signal)s
>> +Hostname: %(hostname)s
>> +Time of the crash: %(time)s
>> +Program backtrace:
>> +%(backtrace)s
>> +""" % format_dict
>> +
>> +        syslog.syslog(syslog.LOG_INFO,
>> +                      "Application %s, PID %s crashed" %
>> +                      (exe_path, crashed_pid))
>> +
>> +        # Now, for all results dir, let's create the directory if it doesn't
>> +        # exist, and write the core file and the report to it.
>> +        syslog.syslog(syslog.LOG_INFO,
>> +                      "Writing core files and reports to %s" %
>> +                      current_results_dir_list)
>> +        for result_dir in current_results_dir_list:
>> +            if not os.path.isdir(result_dir):
>> +                os.makedirs(result_dir)
>> +            core_path = os.path.join(result_dir, 'core')
>> +            write_to_file(core_path, core_file)
>> +            report_path = os.path.join(result_dir, 'report')
>> +            write_to_file(report_path, report)
>> +
>> +    finally:
>> +        # Cleanup temporary directories
>> +        shutil.rmtree(core_tmp_dir)
>> --
>> 1.6.2.5
>>
>> _______________________________________________
>> Autotest mailing list
>> [e-mail]
>> http://test.kernel.org/cgi-bin/mailman/listinfo/autotest
>>
>
>
>
> --
> Lucas
>
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John Admanski Sept. 15, 2009, 6:50 p.m. UTC | #3

I do have one major concern; other than that, it looks pretty good to
me. I think Michael's suggestions are generally reasonable (although
I'm fine with the code as it is as well). But if you do use his
suggested get_results_dir_list please use "pid in pid_dir_dict" and
not "pid_dir_dict.has_key(pid)".

-- John

On Tue, Sep 8, 2009 at 6:53 AM, Lucas Meneghel Rodrigues <[e-mail]> wrote:
> This patch adds a system to watch user space segmentation
> faults, writing core dumps and some degree of core dump
> analysis report. We believe that such a system will be
> beneficial for autotest as a whole, since the ability to
> get core dumps and dump analysis for each app crashing
> during an autotest execution can help test engineers with
> richer debugging information.
>
> The system is comprised by 2 parts:
>
>  * Modifications on test code that enable core dumps
> generation, register a core handler script in the kernel
> and check by generated core files at the end of each
> test.
>
>  * A core handler script that is going to write the
> core on each test debug dir in a convenient way, with
> a report that currently is comprised by the process that
> died and a gdb stacktrace of the process. As the system
> gets in shape, we could add more scripts that can do
> fancier stuff (such as handlers that use frysk to get
> more info such as memory maps, provided that we have
> frysk installed in the machine).
>
> This is the proof of concept of the system. I am sending it
> to the mailing list on this early stage so I can get
> feedback on the feature. The system passes my basic
> tests:
>
>  * Run a simple long test, such as the kvm test, and
> then crash an application while the test is running. I
> get reports generated on test.debugdir
>
>  * Run a slightly more complex control file, with 3 parallel
> bonnie instances at once and crash an application while the
> test is running. I get reports generated on all
> test.debugdirs.
>
> 3rd try:
>  * Explicitely enable core dumps using the resource module
>  * Fixed a bug on the crash detection code, and factored
>   it into a utility function.
>
> I believe we are good to go now.
>
> Signed-off-by: Lucas Meneghel Rodrigues <[e-mail]>
> ---
>  client/common_lib/test.py     |   66 +++++++++++++-
>  client/tools/crash_handler.py |  202 +++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 266 insertions(+), 2 deletions(-)
>  create mode 100755 client/tools/crash_handler.py
>
> diff --git a/client/common_lib/test.py b/client/common_lib/test.py
> index 362c960..65b78a3 100644
> --- a/client/common_lib/test.py
> +++ b/client/common_lib/test.py
> @@ -17,7 +17,7 @@
>  #       tmpdir          eg. tmp/<tempname>_<testname.tag>
>
>  import fcntl, os, re, sys, shutil, tarfile, tempfile, time, traceback
> -import warnings, logging
> +import warnings, logging, glob, resource
>
>  from autotest_lib.client.common_lib import error
>  from autotest_lib.client.bin import utils
> @@ -31,7 +31,6 @@ class base_test:
>         self.job = job
>         self.pkgmgr = job.pkgmgr
>         self.autodir = job.autodir
> -
>         self.outputdir = outputdir
>         self.tagged_testname = os.path.basename(self.outputdir)
>         self.resultsdir = os.path.join(self.outputdir, 'results')
> @@ -40,6 +39,7 @@ class base_test:
>         os.mkdir(self.profdir)
>         self.debugdir = os.path.join(self.outputdir, 'debug')
>         os.mkdir(self.debugdir)
> +        self.configure_crash_handler()
>         self.bindir = bindir
>         if hasattr(job, 'libdir'):
>             self.libdir = job.libdir
> @@ -54,6 +54,66 @@ class base_test:
>         self.after_iteration_hooks = []
>
>
> +    def configure_crash_handler(self):
> +        """
> +        Configure the crash handler by:
> +         * Setting up core size to unlimited
> +         * Putting an appropriate crash handler on /proc/sys/kernel/core_pattern
> +         * Create files that the crash handler will use to figure which tests
> +           are active at a given moment
> +
> +        The crash handler will pick up the core file and write it to
> +        self.debugdir, and perform analysis on it to generate a report. The
> +        program also outputs some results to syslog.
> +
> +        If multiple tests are running, an attempt to verify if we still have
> +        the old PID on the system process table to determine whether it is a
> +        parent of the current test execution. If we can't determine it, the
> +        core file and the report file will be copied to all test debug dirs.
> +        """
> +        self.pattern_file = '/proc/sys/kernel/core_pattern'
> +        try:
> +            # Enable core dumps
> +            resource.setrlimit(resource.RLIMIT_CORE, (-1, -1))
> +            # Trying to backup core pattern and register our script
> +            self.core_pattern_backup = open(self.pattern_file, 'r').read()
> +            pattern_file = open(self.pattern_file, 'w')
> +            tools_dir = os.path.join(self.autodir, 'tools')
> +            crash_handler_path = os.path.join(tools_dir, 'crash_handler.py')
> +            pattern_file.write('|' + crash_handler_path + ' %p %t %u %s %h %e')
> +            # Writing the files that the crash handler is going to use
> +            self.debugdir_tmp_file = ('/tmp/autotest_results_dir.%s' %
> +                                      os.getpid())
> +            utils.open_write_close(self.debugdir_tmp_file, self.debugdir + "\n")
> +        except Exception, e:
> +            self.crash_handling_enabled = False
> +            logging.error('Crash handling system disabled: %s' % e)
> +        else:
> +            self.crash_handling_enabled = True
> +            logging.debug('Crash handling system enabled.')
> +
> +
> +    def crash_handler_report(self):
> +        """
> +        If core dumps are found on the debugdir after the execution of the
> +        test, let the user know.
> +        """
> +        if self.crash_handling_enabled:
> +            core_dirs = glob.glob('%s/crash.*' % self.debugdir)
> +            if core_dirs:
> +                logging.warning('Programs crashed during test execution:')
> +                for dir in core_dirs:
> +                    logging.warning('Please verify %s for more info', dir)
> +            # Remove the debugdir info file
> +            os.unlink(self.debugdir_tmp_file)
> +            # Restore the core pattern backup
> +            try:
> +                utils.open_write_close(self.pattern_file,
> +                                       self.core_pattern_backup)
> +            except EnvironmentError:
> +                pass
> +
> +
>     def assert_(self, expr, msg='Assertion failed.'):
>         if not expr:
>             raise error.TestError(msg)
> @@ -377,6 +437,7 @@ class base_test:
>                         traceback.print_exc()
>                         print 'Now raising the earlier %s error' % exc_info[0]
>                 finally:
> +                    self.crash_handler_report()

If this is going to be put in front of the logging.restore call, it
probably needs to be wrapped in its own try-finally (with the
logging.restore in the finally). Otherwise if it fails for any reason
it's going to mess up all subsequent logging.

>                     self.job.logging.restore()
>                     try:
>                         raise exc_info[0], exc_info[1], exc_info[2]
> @@ -389,6 +450,7 @@ class base_test:
>                     if run_cleanup:
>                         _cherry_pick_call(self.cleanup, *args, **dargs)
>                 finally:
> +                    self.crash_handler_report()

Same comment as above here.

>                     self.job.logging.restore()
>         except error.AutotestError:
>             if self.network_destabilizing:
> diff --git a/client/tools/crash_handler.py b/client/tools/crash_handler.py
> new file mode 100755
> index 0000000..e281eb5
> --- /dev/null
> +++ b/client/tools/crash_handler.py
> @@ -0,0 +1,202 @@
> +#!/usr/bin/python
> +"""
> +Simple crash handling application for autotest
> +
> +@copyright Red Hat Inc 2009
> +@author Lucas Meneghel Rodrigues <[e-mail]>
> +"""
> +import sys, os, commands, glob, tempfile, shutil, syslog
> +
> +
> +def get_parent_pid(pid):
> +    """
> +    Returns the parent PID for a given PID, converted to an integer.
> +
> +    @param pid: Process ID.
> +    """
> +    try:
> +        stat_file_contents = open('/proc/%s/stat' % pid, 'r').readline()
> +        ppid = int(stat_file_contents.split(" ")[3])
> +    except:
> +        # It is not possible to determine the parent because the process
> +        # already left the process table.
> +        ppid = 1
> +
> +    return ppid
> +
> +
> +def pid_descends_from(pid_a, pid_b):
> +    """
> +    Check whether pid_a descends from pid_b.
> +
> +    @param pid_a: Process ID.
> +    @param pid_b: Process ID.
> +    """
> +    pid_a = int(pid_a)
> +    pid_b = int(pid_b)
> +    current_pid = pid_a
> +    while current_pid > 1:
> +        if current_pid == pid_b:
> +            syslog.syslog(syslog.LOG_INFO,
> +                          "PID %s descends from PID %s!" % (pid_a, pid_b))
> +            return True
> +        else:
> +            current_pid = get_parent_pid(current_pid)
> +    syslog.syslog(syslog.LOG_INFO,
> +                  "PID %s does not descend from PID %s" % (pid_a, pid_b))
> +    return False
> +
> +
> +def write_to_file(file_path, contents):
> +    """
> +    Write contents to a given file path specified. If not specified, the file
> +    will be created.
> +
> +    @param file_path: Path to a given file.
> +    @param contents: File contents.
> +    """
> +    file_object = open(file_path, 'w')
> +    file_object.write(contents)
> +    file_object.close()
> +
> +
> +def get_results_dir_list(pid, core_dir_basename):
> +    """
> +    Get all valid output directories for the core file and the report. It works
> +    by inspecting files created by each test on /tmp and verifying if the
> +    PID of the process that crashed is a child or grandchild of the autotest
> +    test process. If it can't find any relationship (maybe a daemon that died
> +    during a test execution), it will write the core file to the debug dirs
> +    of all tests currently being executed. If there are no active autotest
> +    tests at a particular moment, it will return a list with ['/tmp'].
> +
> +    @param pid: PID for the process that generated the core
> +    @param core_dir_basename: Basename for the directory that will hold both
> +            the core dump and the crash report.
> +    """
> +    # Get all active test debugdir path files present
> +    debugdir_files = glob.glob("/tmp/autotest_results_dir.*")
> +    if debugdir_files:
> +        pid_dir_dict = {}
> +        for debugdir_file in debugdir_files:
> +            a_pid = debugdir_file.split('.')[-1]
> +            results_dir = open(debugdir_file, 'r').read().strip()
> +            pid_dir_dict[a_pid] = os.path.join(results_dir, core_dir_basename)
> +
> +        results_dir_list = []
> +        found_relation = False
> +        for a_pid, a_path in pid_dir_dict.iteritems():
> +            if pid_descends_from(pid, a_pid):
> +                results_dir_list.append(a_path)
> +                found_relation = True
> +
> +        # If we could not find any relations between the pids in the list with
> +        # the process that crashed, we can't tell for sure which test spawned
> +        # the process (maybe it is a daemon and started even before autotest
> +        # started), so we will have to output the core file to all active test
> +        # directories.
> +        if not found_relation:
> +            return pid_dir_dict.values()
> +        else:
> +            return results_dir_list
> +
> +    else:
> +        path_inactive_autotest = os.path.join('/tmp', core_dir_basename)
> +        return [path_inactive_autotest]
> +
> +
> +def get_info_from_core(path):
> +    """
> +    Reads a core file and extracts a dictionary with useful core information.
> +    Right now, the only information extracted is the full executable name.
> +
> +    @param path: Path to core file.
> +    """
> +    # Here we are getting the executable full path in a very inelegant way :(
> +    # Since the 'right' solution for it is to make a library to get information
> +    # from core dump files, properly written, I'll leave this as it is for now.
> +    full_exe_path = commands.getoutput('strings %s | grep "_="' %
> +                                       path).strip("_=")
> +    if full_exe_path.startswith("./"):
> +        pwd = commands.getoutput('strings %s | grep "^PWD="' %
> +                                 path).strip("PWD=")
> +        full_exe_path = os.path.join(pwd, full_exe_path.strip("./"))
> +
> +    return {'core_file': path, 'full_exe_path': full_exe_path}
> +
> +
> +if __name__ == "__main__":
> +    syslog.openlog('AutotestCrashHandler', 0, syslog.LOG_DAEMON)
> +    (crashed_pid, time, uid, signal, hostname, exe) = sys.argv[1:]
> +    core_name = 'core'
> +    report_name = 'report'
> +    core_dir_name = 'crash.%s.%s' % (exe, crashed_pid)
> +    core_tmp_dir = tempfile.mkdtemp(prefix='core_', dir='/tmp')
> +    core_tmp_path = os.path.join(core_tmp_dir, core_name)
> +    gdb_command_path = os.path.join(core_tmp_dir, 'gdb_command')
> +
> +    try:
> +        # Get the filtered results dir list
> +        current_results_dir_list = get_results_dir_list(crashed_pid,
> +                                                        core_dir_name)
> +
> +        # Write the core file to the appropriate directory
> +        # (we are piping it to this script)
> +        core_file = sys.stdin.read()
> +        write_to_file(core_tmp_path, core_file)
> +
> +        # Write a command file for GDB
> +        gdb_command = 'bt full\n'
> +        write_to_file(gdb_command_path, gdb_command)
> +
> +        # Get full command path
> +        exe_path = get_info_from_core(core_tmp_path)['full_exe_path']
> +
> +        # Take a backtrace from the running program
> +        gdb_cmd = 'gdb -e %s -c %s -x %s -n -batch -quiet' % (exe_path,
> +                                                              core_tmp_path,
> +                                                              gdb_command_path)
> +        backtrace = commands.getoutput(gdb_cmd)
> +        # Sanitize output before passing it to the report
> +        backtrace = backtrace.decode('utf-8', 'ignore')
> +
> +        # Composing the format_dict
> +        format_dict = {}
> +        format_dict['program'] = exe_path
> +        format_dict['pid'] = crashed_pid
> +        format_dict['signal'] = signal
> +        format_dict['hostname'] = hostname
> +        format_dict['time'] = time
> +        format_dict['backtrace'] = backtrace
> +
> +        report = """Autotest crash report
> +
> +Program: %(program)s
> +PID: %(pid)s
> +Signal: %(signal)s
> +Hostname: %(hostname)s
> +Time of the crash: %(time)s
> +Program backtrace:
> +%(backtrace)s
> +""" % format_dict
> +
> +        syslog.syslog(syslog.LOG_INFO,
> +                      "Application %s, PID %s crashed" %
> +                      (exe_path, crashed_pid))
> +
> +        # Now, for all results dir, let's create the directory if it doesn't
> +        # exist, and write the core file and the report to it.
> +        syslog.syslog(syslog.LOG_INFO,
> +                      "Writing core files and reports to %s" %
> +                      current_results_dir_list)
> +        for result_dir in current_results_dir_list:
> +            if not os.path.isdir(result_dir):
> +                os.makedirs(result_dir)
> +            core_path = os.path.join(result_dir, 'core')
> +            write_to_file(core_path, core_file)
> +            report_path = os.path.join(result_dir, 'report')
> +            write_to_file(report_path, report)
> +
> +    finally:
> +        # Cleanup temporary directories
> +        shutil.rmtree(core_tmp_dir)
> --
> 1.6.2.5
>
>
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Patch

diff --git a/client/common_lib/test.py b/client/common_lib/test.py
index 362c960..65b78a3 100644
--- a/client/common_lib/test.py
+++ b/client/common_lib/test.py
@@ -17,7 +17,7 @@ 
 #       tmpdir          eg. tmp/<tempname>_<testname.tag>
 
 import fcntl, os, re, sys, shutil, tarfile, tempfile, time, traceback
-import warnings, logging
+import warnings, logging, glob, resource
 
 from autotest_lib.client.common_lib import error
 from autotest_lib.client.bin import utils
@@ -31,7 +31,6 @@  class base_test:
         self.job = job
         self.pkgmgr = job.pkgmgr
         self.autodir = job.autodir
-
         self.outputdir = outputdir
         self.tagged_testname = os.path.basename(self.outputdir)
         self.resultsdir = os.path.join(self.outputdir, 'results')
@@ -40,6 +39,7 @@  class base_test:
         os.mkdir(self.profdir)
         self.debugdir = os.path.join(self.outputdir, 'debug')
         os.mkdir(self.debugdir)
+        self.configure_crash_handler()
         self.bindir = bindir
         if hasattr(job, 'libdir'):
             self.libdir = job.libdir
@@ -54,6 +54,66 @@  class base_test:
         self.after_iteration_hooks = []
 
 
+    def configure_crash_handler(self):
+        """
+        Configure the crash handler by:
+         * Setting up core size to unlimited
+         * Putting an appropriate crash handler on /proc/sys/kernel/core_pattern
+         * Create files that the crash handler will use to figure which tests
+           are active at a given moment
+
+        The crash handler will pick up the core file and write it to
+        self.debugdir, and perform analysis on it to generate a report. The
+        program also outputs some results to syslog.
+
+        If multiple tests are running, an attempt to verify if we still have
+        the old PID on the system process table to determine whether it is a
+        parent of the current test execution. If we can't determine it, the
+        core file and the report file will be copied to all test debug dirs.
+        """
+        self.pattern_file = '/proc/sys/kernel/core_pattern'
+        try:
+            # Enable core dumps
+            resource.setrlimit(resource.RLIMIT_CORE, (-1, -1))
+            # Trying to backup core pattern and register our script
+            self.core_pattern_backup = open(self.pattern_file, 'r').read()
+            pattern_file = open(self.pattern_file, 'w')
+            tools_dir = os.path.join(self.autodir, 'tools')
+            crash_handler_path = os.path.join(tools_dir, 'crash_handler.py')
+            pattern_file.write('|' + crash_handler_path + ' %p %t %u %s %h %e')
+            # Writing the files that the crash handler is going to use
+            self.debugdir_tmp_file = ('/tmp/autotest_results_dir.%s' %
+                                      os.getpid())
+            utils.open_write_close(self.debugdir_tmp_file, self.debugdir + "\n")
+        except Exception, e:
+            self.crash_handling_enabled = False
+            logging.error('Crash handling system disabled: %s' % e)
+        else:
+            self.crash_handling_enabled = True
+            logging.debug('Crash handling system enabled.')
+
+
+    def crash_handler_report(self):
+        """
+        If core dumps are found on the debugdir after the execution of the
+        test, let the user know.
+        """
+        if self.crash_handling_enabled:
+            core_dirs = glob.glob('%s/crash.*' % self.debugdir)
+            if core_dirs:
+                logging.warning('Programs crashed during test execution:')
+                for dir in core_dirs:
+                    logging.warning('Please verify %s for more info', dir)
+            # Remove the debugdir info file
+            os.unlink(self.debugdir_tmp_file)
+            # Restore the core pattern backup
+            try:
+                utils.open_write_close(self.pattern_file,
+                                       self.core_pattern_backup)
+            except EnvironmentError:
+                pass
+
+
     def assert_(self, expr, msg='Assertion failed.'):
         if not expr:
             raise error.TestError(msg)
@@ -377,6 +437,7 @@  class base_test:
                         traceback.print_exc()
                         print 'Now raising the earlier %s error' % exc_info[0]
                 finally:
+                    self.crash_handler_report()
                     self.job.logging.restore()
                     try:
                         raise exc_info[0], exc_info[1], exc_info[2]
@@ -389,6 +450,7 @@  class base_test:
                     if run_cleanup:
                         _cherry_pick_call(self.cleanup, *args, **dargs)
                 finally:
+                    self.crash_handler_report()
                     self.job.logging.restore()
         except error.AutotestError:
             if self.network_destabilizing:
diff --git a/client/tools/crash_handler.py b/client/tools/crash_handler.py
new file mode 100755
index 0000000..e281eb5
--- /dev/null
+++ b/client/tools/crash_handler.py
@@ -0,0 +1,202 @@ 
+#!/usr/bin/python
+"""
+Simple crash handling application for autotest
+
+@copyright Red Hat Inc 2009
+@author Lucas Meneghel Rodrigues <[e-mail]>
+"""
+import sys, os, commands, glob, tempfile, shutil, syslog
+
+
+def get_parent_pid(pid):
+    """
+    Returns the parent PID for a given PID, converted to an integer.
+
+    @param pid: Process ID.
+    """
+    try:
+        stat_file_contents = open('/proc/%s/stat' % pid, 'r').readline()
+        ppid = int(stat_file_contents.split(" ")[3])
+    except:
+        # It is not possible to determine the parent because the process
+        # already left the process table.
+        ppid = 1
+
+    return ppid
+
+
+def pid_descends_from(pid_a, pid_b):
+    """
+    Check whether pid_a descends from pid_b.
+
+    @param pid_a: Process ID.
+    @param pid_b: Process ID.
+    """
+    pid_a = int(pid_a)
+    pid_b = int(pid_b)
+    current_pid = pid_a
+    while current_pid > 1:
+        if current_pid == pid_b:
+            syslog.syslog(syslog.LOG_INFO,
+                          "PID %s descends from PID %s!" % (pid_a, pid_b))
+            return True
+        else:
+            current_pid = get_parent_pid(current_pid)
+    syslog.syslog(syslog.LOG_INFO,
+                  "PID %s does not descend from PID %s" % (pid_a, pid_b))
+    return False
+
+
+def write_to_file(file_path, contents):
+    """
+    Write contents to a given file path specified. If not specified, the file
+    will be created.
+
+    @param file_path: Path to a given file.
+    @param contents: File contents.
+    """
+    file_object = open(file_path, 'w')
+    file_object.write(contents)
+    file_object.close()
+
+
+def get_results_dir_list(pid, core_dir_basename):
+    """
+    Get all valid output directories for the core file and the report. It works
+    by inspecting files created by each test on /tmp and verifying if the
+    PID of the process that crashed is a child or grandchild of the autotest
+    test process. If it can't find any relationship (maybe a daemon that died
+    during a test execution), it will write the core file to the debug dirs
+    of all tests currently being executed. If there are no active autotest
+    tests at a particular moment, it will return a list with ['/tmp'].
+
+    @param pid: PID for the process that generated the core
+    @param core_dir_basename: Basename for the directory that will hold both
+            the core dump and the crash report.
+    """
+    # Get all active test debugdir path files present
+    debugdir_files = glob.glob("/tmp/autotest_results_dir.*")
+    if debugdir_files:
+        pid_dir_dict = {}
+        for debugdir_file in debugdir_files:
+            a_pid = debugdir_file.split('.')[-1]
+            results_dir = open(debugdir_file, 'r').read().strip()
+            pid_dir_dict[a_pid] = os.path.join(results_dir, core_dir_basename)
+
+        results_dir_list = []
+        found_relation = False
+        for a_pid, a_path in pid_dir_dict.iteritems():
+            if pid_descends_from(pid, a_pid):
+                results_dir_list.append(a_path)
+                found_relation = True
+
+        # If we could not find any relations between the pids in the list with
+        # the process that crashed, we can't tell for sure which test spawned
+        # the process (maybe it is a daemon and started even before autotest
+        # started), so we will have to output the core file to all active test
+        # directories.
+        if not found_relation:
+            return pid_dir_dict.values()
+        else:
+            return results_dir_list
+
+    else:
+        path_inactive_autotest = os.path.join('/tmp', core_dir_basename)
+        return [path_inactive_autotest]
+
+
+def get_info_from_core(path):
+    """
+    Reads a core file and extracts a dictionary with useful core information.
+    Right now, the only information extracted is the full executable name.
+
+    @param path: Path to core file.
+    """
+    # Here we are getting the executable full path in a very inelegant way :(
+    # Since the 'right' solution for it is to make a library to get information
+    # from core dump files, properly written, I'll leave this as it is for now.
+    full_exe_path = commands.getoutput('strings %s | grep "_="' %
+                                       path).strip("_=")
+    if full_exe_path.startswith("./"):
+        pwd = commands.getoutput('strings %s | grep "^PWD="' %
+                                 path).strip("PWD=")
+        full_exe_path = os.path.join(pwd, full_exe_path.strip("./"))
+
+    return {'core_file': path, 'full_exe_path': full_exe_path}
+
+
+if __name__ == "__main__":
+    syslog.openlog('AutotestCrashHandler', 0, syslog.LOG_DAEMON)
+    (crashed_pid, time, uid, signal, hostname, exe) = sys.argv[1:]
+    core_name = 'core'
+    report_name = 'report'
+    core_dir_name = 'crash.%s.%s' % (exe, crashed_pid)
+    core_tmp_dir = tempfile.mkdtemp(prefix='core_', dir='/tmp')
+    core_tmp_path = os.path.join(core_tmp_dir, core_name)
+    gdb_command_path = os.path.join(core_tmp_dir, 'gdb_command')
+
+    try:
+        # Get the filtered results dir list
+        current_results_dir_list = get_results_dir_list(crashed_pid,
+                                                        core_dir_name)
+
+        # Write the core file to the appropriate directory
+        # (we are piping it to this script)
+        core_file = sys.stdin.read()
+        write_to_file(core_tmp_path, core_file)
+
+        # Write a command file for GDB
+        gdb_command = 'bt full\n'
+        write_to_file(gdb_command_path, gdb_command)
+
+        # Get full command path
+        exe_path = get_info_from_core(core_tmp_path)['full_exe_path']
+
+        # Take a backtrace from the running program
+        gdb_cmd = 'gdb -e %s -c %s -x %s -n -batch -quiet' % (exe_path,
+                                                              core_tmp_path,
+                                                              gdb_command_path)
+        backtrace = commands.getoutput(gdb_cmd)
+        # Sanitize output before passing it to the report
+        backtrace = backtrace.decode('utf-8', 'ignore')
+
+        # Composing the format_dict
+        format_dict = {}
+        format_dict['program'] = exe_path
+        format_dict['pid'] = crashed_pid
+        format_dict['signal'] = signal
+        format_dict['hostname'] = hostname
+        format_dict['time'] = time
+        format_dict['backtrace'] = backtrace
+
+        report = """Autotest crash report
+
+Program: %(program)s
+PID: %(pid)s
+Signal: %(signal)s
+Hostname: %(hostname)s
+Time of the crash: %(time)s
+Program backtrace:
+%(backtrace)s
+""" % format_dict
+
+        syslog.syslog(syslog.LOG_INFO,
+                      "Application %s, PID %s crashed" %
+                      (exe_path, crashed_pid))
+
+        # Now, for all results dir, let's create the directory if it doesn't
+        # exist, and write the core file and the report to it.
+        syslog.syslog(syslog.LOG_INFO,
+                      "Writing core files and reports to %s" %
+                      current_results_dir_list)
+        for result_dir in current_results_dir_list:
+            if not os.path.isdir(result_dir):
+                os.makedirs(result_dir)
+            core_path = os.path.join(result_dir, 'core')
+            write_to_file(core_path, core_file)
+            report_path = os.path.join(result_dir, 'report')
+            write_to_file(report_path, report)
+
+    finally:
+        # Cleanup temporary directories
+        shutil.rmtree(core_tmp_dir)