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Posted to dev@httpd.apache.org by Eric Covener <co...@gmail.com> on 2018/02/19 23:57:09 UTC
Re: win32: disable shared LDAP cache by default
I am hoping this is fixed by
http://svn.apache.org/viewvc?view=revision&revision=182481 which I
stumbled onto from another direction.
On Thu, Aug 3, 2017 at 5:58 AM, Stefan Sperling <st...@apache.org> wrote:
> There are numerous reports of Apache HTTPD looping forever on Windows
> unless the LDAPSharedCacheSize option is set to zero.
>
> See for instance:
> https://svn.haxx.se/users/archive-2014-05/0000.shtml
> https://subversion.open.collab.net/ds/viewMessage.do?dsMessageId=564176&dsForumId=3
> https://subversion.open.collab.net/ds/viewMessage.do?dsForumId=3&viewType=browseAll&dsMessageId=539507
> https://stackoverflow.com/questions/44542654/collabnet-subversion-server-reaching-cpu-100-because-of-httpd-exe-process
>
> I looked around for a while but don't know yet if a corresponding issue
> in the HTTPD bug tracker exists. Does anyone know?
>
> On the surface it looks like a memory pool corruption bug to me.
> The stack trace posted in https://svn.haxx.se/users/archive-2014-05/0000.shtml
> points towards an endless loop in apr_pool_cleanup_kill().
> The trace ends at APR-util's misc/apr_reslist.c:apr_reslist_cleanup_order_set,
> and of the functions this calls only apr_pool_cleanup_kill() contains loops.
>
> I could not do any further debugging since I only had a production setup
> to look at, which is stable with the workaround 'LDAPSharedCacheSize 0'.
> I also do not have a Windows dev environment and I don't plan on digging
> any further.
>
> Until the real bug gets found and fixed, I would recommend making the
> known workaround the default on Windows. Because the winnt MPM runs a
> single process, there is no benefit to a shared memory cache anyway.
>
> Should I commit this patch?
>
> Index: modules/ldap/util_ldap.c
> ===================================================================
> --- modules/ldap/util_ldap.c (revision 1803972)
> +++ modules/ldap/util_ldap.c (working copy)
> @@ -2815,7 +2815,17 @@ static void *util_ldap_create_config(apr_pool_t *p
> apr_thread_mutex_create(&st->mutex, APR_THREAD_MUTEX_DEFAULT, st->pool);
> #endif
>
> +#ifdef WIN32
> + /* XXX The shared memory cache can cause an endless loop on Windows.
> + * See https://svn.haxx.se/users/archive-2014-05/0000.shtml and
> + * similar reports elsewhere which recommend 'LDAPSharedCacheSize 0'
> + * as a workaround.
> + * Because the winnt MPM uses a single process a shared cache is
> + * not needed anyway so leave it disabled by default. */
> + st->cache_bytes = 0;
> +#else
> st->cache_bytes = 500000;
> +#endif
> st->search_cache_ttl = 600000000;
> st->search_cache_size = 1024;
> st->compare_cache_ttl = 600000000;
--
Eric Covener
covener@gmail.com
Re: win32: disable shared LDAP cache by default
Posted by Eric Covener <co...@gmail.com>.
whoops, http://svn.apache.org/viewvc?view=revision&revision=1824811
On Tue, Feb 20, 2018 at 5:42 PM, William A Rowe Jr <wr...@rowe-clan.net> wrote:
> Which patch? I think you are missing a digit.
>
> On Mon, Feb 19, 2018 at 5:57 PM, Eric Covener <co...@gmail.com> wrote:
>> I am hoping this is fixed by
>> http://svn.apache.org/viewvc?view=revision&revision=182481 which I
>> stumbled onto from another direction.
>>
>> On Thu, Aug 3, 2017 at 5:58 AM, Stefan Sperling <st...@apache.org> wrote:
>>> There are numerous reports of Apache HTTPD looping forever on Windows
>>> unless the LDAPSharedCacheSize option is set to zero.
>>>
>>> See for instance:
>>> https://svn.haxx.se/users/archive-2014-05/0000.shtml
>>> https://subversion.open.collab.net/ds/viewMessage.do?dsMessageId=564176&dsForumId=3
>>> https://subversion.open.collab.net/ds/viewMessage.do?dsForumId=3&viewType=browseAll&dsMessageId=539507
>>> https://stackoverflow.com/questions/44542654/collabnet-subversion-server-reaching-cpu-100-because-of-httpd-exe-process
>>>
>>> I looked around for a while but don't know yet if a corresponding issue
>>> in the HTTPD bug tracker exists. Does anyone know?
>>>
>>> On the surface it looks like a memory pool corruption bug to me.
>>> The stack trace posted in https://svn.haxx.se/users/archive-2014-05/0000.shtml
>>> points towards an endless loop in apr_pool_cleanup_kill().
>>> The trace ends at APR-util's misc/apr_reslist.c:apr_reslist_cleanup_order_set,
>>> and of the functions this calls only apr_pool_cleanup_kill() contains loops.
>>>
>>> I could not do any further debugging since I only had a production setup
>>> to look at, which is stable with the workaround 'LDAPSharedCacheSize 0'.
>>> I also do not have a Windows dev environment and I don't plan on digging
>>> any further.
>>>
>>> Until the real bug gets found and fixed, I would recommend making the
>>> known workaround the default on Windows. Because the winnt MPM runs a
>>> single process, there is no benefit to a shared memory cache anyway.
>>>
>>> Should I commit this patch?
>>>
>>> Index: modules/ldap/util_ldap.c
>>> ===================================================================
>>> --- modules/ldap/util_ldap.c (revision 1803972)
>>> +++ modules/ldap/util_ldap.c (working copy)
>>> @@ -2815,7 +2815,17 @@ static void *util_ldap_create_config(apr_pool_t *p
>>> apr_thread_mutex_create(&st->mutex, APR_THREAD_MUTEX_DEFAULT, st->pool);
>>> #endif
>>>
>>> +#ifdef WIN32
>>> + /* XXX The shared memory cache can cause an endless loop on Windows.
>>> + * See https://svn.haxx.se/users/archive-2014-05/0000.shtml and
>>> + * similar reports elsewhere which recommend 'LDAPSharedCacheSize 0'
>>> + * as a workaround.
>>> + * Because the winnt MPM uses a single process a shared cache is
>>> + * not needed anyway so leave it disabled by default. */
>>> + st->cache_bytes = 0;
>>> +#else
>>> st->cache_bytes = 500000;
>>> +#endif
>>> st->search_cache_ttl = 600000000;
>>> st->search_cache_size = 1024;
>>> st->compare_cache_ttl = 600000000;
>>
>>
>>
>> --
>> Eric Covener
>> covener@gmail.com
--
Eric Covener
covener@gmail.com
Re: win32: disable shared LDAP cache by default
Posted by William A Rowe Jr <wr...@rowe-clan.net>.
Which patch? I think you are missing a digit.
On Mon, Feb 19, 2018 at 5:57 PM, Eric Covener <co...@gmail.com> wrote:
> I am hoping this is fixed by
> http://svn.apache.org/viewvc?view=revision&revision=182481 which I
> stumbled onto from another direction.
>
> On Thu, Aug 3, 2017 at 5:58 AM, Stefan Sperling <st...@apache.org> wrote:
>> There are numerous reports of Apache HTTPD looping forever on Windows
>> unless the LDAPSharedCacheSize option is set to zero.
>>
>> See for instance:
>> https://svn.haxx.se/users/archive-2014-05/0000.shtml
>> https://subversion.open.collab.net/ds/viewMessage.do?dsMessageId=564176&dsForumId=3
>> https://subversion.open.collab.net/ds/viewMessage.do?dsForumId=3&viewType=browseAll&dsMessageId=539507
>> https://stackoverflow.com/questions/44542654/collabnet-subversion-server-reaching-cpu-100-because-of-httpd-exe-process
>>
>> I looked around for a while but don't know yet if a corresponding issue
>> in the HTTPD bug tracker exists. Does anyone know?
>>
>> On the surface it looks like a memory pool corruption bug to me.
>> The stack trace posted in https://svn.haxx.se/users/archive-2014-05/0000.shtml
>> points towards an endless loop in apr_pool_cleanup_kill().
>> The trace ends at APR-util's misc/apr_reslist.c:apr_reslist_cleanup_order_set,
>> and of the functions this calls only apr_pool_cleanup_kill() contains loops.
>>
>> I could not do any further debugging since I only had a production setup
>> to look at, which is stable with the workaround 'LDAPSharedCacheSize 0'.
>> I also do not have a Windows dev environment and I don't plan on digging
>> any further.
>>
>> Until the real bug gets found and fixed, I would recommend making the
>> known workaround the default on Windows. Because the winnt MPM runs a
>> single process, there is no benefit to a shared memory cache anyway.
>>
>> Should I commit this patch?
>>
>> Index: modules/ldap/util_ldap.c
>> ===================================================================
>> --- modules/ldap/util_ldap.c (revision 1803972)
>> +++ modules/ldap/util_ldap.c (working copy)
>> @@ -2815,7 +2815,17 @@ static void *util_ldap_create_config(apr_pool_t *p
>> apr_thread_mutex_create(&st->mutex, APR_THREAD_MUTEX_DEFAULT, st->pool);
>> #endif
>>
>> +#ifdef WIN32
>> + /* XXX The shared memory cache can cause an endless loop on Windows.
>> + * See https://svn.haxx.se/users/archive-2014-05/0000.shtml and
>> + * similar reports elsewhere which recommend 'LDAPSharedCacheSize 0'
>> + * as a workaround.
>> + * Because the winnt MPM uses a single process a shared cache is
>> + * not needed anyway so leave it disabled by default. */
>> + st->cache_bytes = 0;
>> +#else
>> st->cache_bytes = 500000;
>> +#endif
>> st->search_cache_ttl = 600000000;
>> st->search_cache_size = 1024;
>> st->compare_cache_ttl = 600000000;
>
>
>
> --
> Eric Covener
> covener@gmail.com