[oi-dev] [developer] [Samba] gencache.tdb: device busy
Rouven WEILER
Rouven_Weiler at gmx.net
Sun Apr 21 12:20:32 UTC 2019
Any chance to get to know what happens?
> Am 21.04.2019 um 14:12 schrieb Richard Lowe <richlowe at richlowe.net>:
>
> It's possible there's a bug. It's also possible you're getting really unlucky and the uninitialized mutex looks valid because the magic is valid.
>
>> On Sun, Apr 21, 2019, 06:10 Rouven WEILER <Rouven_Weiler at gmx.net> wrote:
>> Dear all,
>>
>> trying to make samba work and getting rid of my error message
>> [2019/04/01 09:51:41.112485, 0] ../../lib/tdb_wrap/tdb_wrap.c:64(tdb_wrap_log)
>> tdb(/var/samba/lock/gencache.tdb): tdb_open_ex: tdb_mutex_init failed for /var/samba/lock/gencache.tdb: Device busy
>>
>> I followed the info of Youzhong. It definitely works. So thankx.
>> BUT: The OS (OpenIndiana; state of April,19th) is patched against the illumos issue 9959
>>
>> So there might be some mechanism (maybe MUTEX_MAGIC) that avoids the initialization of the mutex before init.
>> I am really not deep in all that pthread stuff…
>>
>> Is there the possiblity that there is a bug in the code base of issue 9959?
>>
>>
>> Best regards
>>
>> Rouven
>>
>>
>>> Am 18.04.2019 um 19:20 schrieb Robert Mustacchi <rm at joyent.com>:
>>>
>>> On 4/18/19 10:12 , Youzhong Yang wrote:
>>>> Little bit confused. The page https://www.openindiana.org/download/ shows
>>>> latest ISO is dated 2018.10, but 9959 fix was submitted on 11/26/2018, I
>>>> guess Hipster doesn't have it.
>>>
>>> The ISO is just the install image. Generally, after using that to
>>> bootstrap, then folks will update to latest bits via IPS. As a result,
>>> the ISO isn't updated (and generally doesn't have to be) quite as often.
>>>
>>> Robert
>>>
>>>> On Thu, Apr 18, 2019 at 12:38 PM Rouven WEILER <Rouven_Weiler at gmx.net>
>>>> wrote:
>>>>
>>>>> On my system the issue is solved and the sources are patched accordingly.
>>>>> Thus, the issue seems to be somewhere else.
>>>>>
>>>>> Am 18.04.2019 um 18:27 schrieb Rouven WEILER <Rouven_Weiler at gmx.net>:
>>>>>
>>>>> concerning openindiana I am using the most recent one. I right now asked
>>>>> if the issue is solved in the latest version.
>>>>>
>>>>> another interesting thing is that older samba versions do not throw EBUSY,
>>>>> although on the same underlying system.
>>>>>
>>>>>
>>>>>
>>>>> Am 18.04.2019 um 18:07 schrieb Youzhong Yang <youzhong at gmail.com>:
>>>>>
>>>>> That is interesting. I am curious about how pthread_mutexattr_init ends up
>>>>> returning EBUSY. What verison of Openindiana are you running? is there a
>>>>> link pointing to the fix that it has for 9959?
>>>>>
>>>>> On Thu, Apr 18, 2019 at 11:53 AM Rouven WEILER <Rouven_Weiler at gmx.net>
>>>>> wrote:
>>>>>
>>>>>> I understand and see that it works, but as written below
>>>>>> pthread_mutexattr_init throws EBUSY, not pthread_mutex_init.
>>>>>>
>>>>>> Also Openindiana seems to include the patch for issue 9959 mentioned. I
>>>>>> will clarify that to make sure.
>>>>>>
>>>>>> I just want to make sure that the patch you suggest aims for the issue
>>>>>> and is not a workaround.
>>>>>>
>>>>>>
>>>>>> Am 18.04.2019 um 16:09 schrieb Youzhong Yang <youzhong at gmail.com>:
>>>>>>
>>>>>> I reproduced the issue on a smartos version which does not have the fix
>>>>>> for https://www.illumos.org/issues/9959.
>>>>>>
>>>>>> The pthread_mutex_init() at line 590 returns EBUSY:
>>>>>> ret = pthread_mutex_init(chain, &ma);
>>>>>>
>>>>>> https://git.samba.org/?p=samba.git;a=blob;f=lib/tdb/common/mutex.c;h=8a122d5d6a2ec321bce25cf06062acc808f1e126;hb=HEAD#l590
>>>>>>
>>>>>>
>>>>>> Then I applied the following patch to lib/tdb/common/mutex.c:
>>>>>>
>>>>>> # git grep -B 1 -n pthread_mutex_init lib/tdb/common/mutex.c
>>>>>> lib/tdb/common/mutex.c-590- bzero(chain,
>>>>>> sizeof(pthread_mutex_t));
>>>>>> lib/tdb/common/mutex.c:591: ret = pthread_mutex_init(chain,
>>>>>> &ma);
>>>>>> --
>>>>>> lib/tdb/common/mutex.c-599- bzero(&m->allrecord_mutex,
>>>>>> sizeof(pthread_mutex_t));
>>>>>> lib/tdb/common/mutex.c:600: ret =
>>>>>> pthread_mutex_init(&m->allrecord_mutex, &ma);
>>>>>> --
>>>>>> lib/tdb/common/mutex.c-693- bzero(&m, sizeof(pthread_mutex_t));
>>>>>> lib/tdb/common/mutex.c:694: ret = pthread_mutex_init(&m, &ma);
>>>>>> --
>>>>>> lib/tdb/common/mutex.c-891- bzero(ptr, sizeof(pthread_mutex_t));
>>>>>> lib/tdb/common/mutex.c:892: ret = pthread_mutex_init(ptr, &ma);
>>>>>>
>>>>>> It works like a charm. Fair enough?
>>>>>>
>>>>>> So again I recommend either of the following two:
>>>>>> - apply 9959 fix to your OS image, or use a newer version which has 9959
>>>>>> fix
>>>>>> - bzero pthread_mutex_t struct before calling pthread_mutex_init().
>>>>>>
>>>>>> In my environment I applied bzero patch to all pthread_mutex_init() calls
>>>>>> in the entire samba code base, you know, who knows what is going to happen.
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Thu, Apr 18, 2019 at 4:29 AM Rouven WEILER <Rouven_Weiler at gmx.net>
>>>>>> wrote:
>>>>>>
>>>>>>> That sounds reasonable!
>>>>>>> Could you help me to dtrace that in a feasible way? Up to now I am not
>>>>>>> used to dtrace. Except knowing what is and that its powerful.
>>>>>>>
>>>>>>> Am 18.04.2019 um 09:29 schrieb Jason King <jason.brian.king at gmail.com>:
>>>>>>>
>>>>>>> It appears that the robust mutexes are mmapped from the .tdb file.
>>>>>>> EBUSY means that the mutex has already been intialized. It also appears
>>>>>>> that if the TDB_CLEAR_IF_FIRST flag is _not_ set when opening the tdb, it
>>>>>>> will try to initialize the mutexes. I’m wondering if the tdb file gets
>>>>>>> created, the memory image of the initialized mutexes is getting saved, then
>>>>>>> when it’s opened again, if that flag is not set, it tries to re-initialize
>>>>>>> the mutexes and fails (because they are already constructed) legitimately
>>>>>>> returning EBUSY. If the samba code is in fact trying to reinitialize an
>>>>>>> already initialized mutex (dtrace might be able to help determine this — at
>>>>>>> this point it’s merely a supposition), that would explain the error.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> From: Rouven WEILER <rouven_weiler at gmx.net> <rouven_weiler at gmx.net>
>>>>>>> Reply: illumos-developer <developer at lists.illumos.org>
>>>>>>> <developer at lists.illumos.org>
>>>>>>> Date: April 18, 2019 at 12:48:48 AM
>>>>>>> To: Youzhong Yang <youzhong at gmail.com> <youzhong at gmail.com>
>>>>>>> Cc: Robert Mustacchi <rm at joyent.com> <rm at joyent.com>, Toomas Soome via
>>>>>>> illumos-developer <developer at lists.illumos.org>
>>>>>>> <developer at lists.illumos.org>
>>>>>>> Subject: [developer] Aw: Re: [Samba] gencache.tdb: device busy
>>>>>>>
>>>>>>> You are totally right. That's the same I got from the man pages.
>>>>>>>
>>>>>>> The responsible code lines of samba also seems to bear no issue and also
>>>>>>> this issue arises on samba version 4.10.x not on earlier ones.
>>>>>>> In addition, there seems to be only a problem with
>>>>>>> illumos/openindiana...
>>>>>>> That's why I do not know how to get that fixed. Up to now I hadn't time
>>>>>>> to dtrace.
>>>>>>>
>>>>>>> Only thing I got so far: When the mutexattr is already set the return
>>>>>>> value will result on undefined behaviour.
>>>>>>> But why only after version 4.10.x on openindiana/illumos?
>>>>>>>
>>>>>>> Just for completion here the codelines of samba:
>>>>>>> https://git.samba.org/?p=samba.git;a=blob;f=lib/tdb/common/mutex.c;h=8a122d5d6a2ec321bce25cf06062acc808f1e126;hb=HEAD#l570
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Gesendet: Mittwoch, 17. April 2019 um 19:19 Uhr
>>>>>>> Von: "Youzhong Yang" <youzhong at gmail.com>
>>>>>>> An: "Rouven WEILER" <Rouven_Weiler at gmx.net>
>>>>>>> Cc: "Robert Mustacchi" <rm at joyent.com>, "Toomas Soome via
>>>>>>> illumos-developer" <developer at lists.illumos.org>
>>>>>>> Betreff: Re: [Samba] gencache.tdb: device busy
>>>>>>>
>>>>>>> Unless I am totally wrong, pthread_mutexattr_init() shouldn't return
>>>>>>> EBUSY:
>>>>>>>
>>>>>>> http://src.illumos.org/source/xref/illumos-gate/usr/src/lib/libc/port/threads/pthr_mutex.c#37
>>>>>>>
>>>>>>>
>>>>>>> On Tue, Apr 16, 2019 at 2:45 PM Rouven WEILER <Rouven_Weiler at gmx.net[
>>>>>>> mailto:Rouven_Weiler at gmx.net <Rouven_Weiler at gmx.net>]> wrote:Hi Robert
>>>>>>> & Youzhong,
>>>>>>>
>>>>>>> I got a response from the Samba-Devs.
>>>>>>> Would the issue mentioned by Youzhong also hot pthread_mutexattr_t?
>>>>>>>
>>>>>>> Concerning dtrace I hadn’t the time yet but I will check for that.
>>>>>>> Is there maybe a way to trace all forks of smbd? Usually the issue
>>>>>>> arises after the fork…
>>>>>>>
>>>>>>> FIND BELOW THE STATEMENT FROM samba.org[http://samba.org]:
>>>>>>>
>>>>>>> This doesn't look exactly the same. In your
>>>>>>> log below you say:
>>>>>>>
>>>>>>> ret = pthread_mutexattr_init(&ma); in line 570
>>>>>>> I got errorno 16 --> device busy.
>>>>>>>
>>>>>>> But the bug report is about needing the value
>>>>>>> passed to pthread_mutex_init() needing to be
>>>>>>> zero, not the value passed to pthread_mutexattr_init().
>>>>>>>
>>>>>>> Can you just try adding '= {0}' to all the
>>>>>>> places where we declare:
>>>>>>>
>>>>>>> pthread_mutexattr_t ma
>>>>>>>
>>>>>>> (i.e. make it say)
>>>>>>>
>>>>>>> pthread_mutexattr_t ma = {0};
>>>>>>>
>>>>>>> and see if it makes your problem go away ?
>>>>>>>
>>>>>>> END OF STATEMENT
>>>>>>>
>>>>>>>
>>>>>>>> Anfang der weitergeleiteten Nachricht:
>>>>>>>>
>>>>>>>> Von: Jeremy Allison via samba <samba at lists.samba.org[
>>>>>>> mailto:samba at lists.samba.org <samba at lists.samba.org>]>
>>>>>>>> Betreff: Aw: [Samba] gencache.tdb: device busy
>>>>>>>> Datum: 16. April 2019 um 02:07:05 MESZ
>>>>>>>> An: Rouven WEILER <Rouven_Weiler at gmx.net[mailto:Rouven_Weiler at gmx.net
>>>>>>> <Rouven_Weiler at gmx.net>]>
>>>>>>>> Kopie: samba at lists.samba.org[mailto:samba at lists.samba.org
>>>>>>> <samba at lists.samba.org>]
>>>>>>>> Antwort an: Jeremy Allison <jra at samba.org[mailto:jra at samba.org
>>>>>>> <jra at samba.org>]>
>>>>>>>>
>>>>>>>> On Fri, Apr 12, 2019 at 09:46:04AM +0200, Rouven WEILER via samba
>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Hi Jeremy,
>>>>>>>>>
>>>>>>>>> I got some info on that topic from the illumos devs:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> It's a sporadic issue, you're lucky enough to not encounter it on
>>>>>>> 4.9.5.
>>>>>>>>>>
>>>>>>>>>> I confirmed in 4.10.2, it happens:
>>>>>>>>>>
>>>>>>>>>> winbindd.log: tdb(/tmw-nas-3p/samba/var/lock/gencache.tdb):
>>>>>>> tdb_open_ex: tdb_mutex_init failed for
>>>>>>> /tmw-nas-3p/samba/var/lock/gencache.tdb: Device busy
>>>>>>>>>>
>>>>>>>>>> So either apply OS fix, or apply a software fix (zeroing
>>>>>>> pthread_mutex_t before pthread_mutex_init()).
>>>>>>>>>
>>>>>>>>> This all should be based on the following issue:
>>>>>>>>>
>>>>>>>>>
>>>>>>> https://www.illumos.org/issues/9959[https://www.illumos.org/issues/9959]
>>>>>>>
>>>>>>>>>
>>>>>>>>> As far as I understand the issue making an software fix in samba for
>>>>>>> the OS seems more reasonable since the problem can occur sporadic and thus
>>>>>>> again...
>>>>>>>>> Could you tell me how to help to fix that bug?
>>>>>>>>
>>>>>>>> This doesn't look exactly the same. In your
>>>>>>>> log below you say:
>>>>>>>>
>>>>>>>> ret = pthread_mutexattr_init(&ma); in line 570
>>>>>>>> I got errorno 16 --> device busy.
>>>>>>>>
>>>>>>>> But the bug report is about needing the value
>>>>>>>> passed to pthread_mutex_init() needing to be
>>>>>>>> zero, not the value passed to pthread_mutexattr_init().
>>>>>>>>
>>>>>>>> Can you just try adding '= {0}' to all the
>>>>>>>> places where we declare:
>>>>>>>>
>>>>>>>> pthread_mutexattr_t ma
>>>>>>>>
>>>>>>>> (i.e. make it say)
>>>>>>>>
>>>>>>>> pthread_mutexattr_t ma = {0};
>>>>>>>>
>>>>>>>> and see if it makes your problem go away ?
>>>>>>>>
>>>>>>>>
>>>>>>>>> Gesendet: Dienstag, 02. April 2019 um 18:59 Uhr
>>>>>>>>> Von: "Jeremy Allison" <jra at samba.org[mailto:jra at samba.org
>>>>>>> <jra at samba.org>]>
>>>>>>>>> An: "Rouven WEILER" <Rouven_Weiler at gmx.net[
>>>>>>> mailto:Rouven_Weiler at gmx.net <Rouven_Weiler at gmx.net>]>
>>>>>>>>> Cc: samba at lists.samba.org[mailto:samba at lists.samba.org
>>>>>>> <samba at lists.samba.org>]
>>>>>>>>> Betreff: Re: Re: [Samba] gencache.tdb: device busy
>>>>>>>>>> On Tue, Apr 02, 2019 at 01:24:19PM +0200, Rouven WEILER wrote:
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> I added LOG statements to mutex.c printing the strerror from the
>>>>>>> return values.
>>>>>>>>>>
>>>>>>>>>> From
>>>>>>>>>>
>>>>>>>>>> ret = pthread_mutexattr_init(&ma); in line 570
>>>>>>>>>>
>>>>>>>>>> I got errorno 16 --> device busy.
>>>>>>>>>>
>>>>>>>>>> But due the manual of pthread_mutex_attr_init() there should only be
>>>>>>> ENOMEM and EINVAL...
>>>>>>>>>>
>>>>>>>>>> Doing gdb smbd -> run
>>>>>>>>>> Doe not reveal anything, but I never used gdb for debugging
>>>>>>> anything. I just gave it a shot...
>>>>>>>>>
>>>>>>>>> Sorry, looks a little like the libc/pthread_mutex support
>>>>>>>>> on Solaris is broken. You might want to raise this on a
>>>>>>>>> Solaris/Illumos forum.
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> To unsubscribe from this list go to the following URL and read the
>>>>>>>>> instructions:
>>>>>>> https://lists.samba.org/mailman/options/samba[https://lists.samba.org/mailman/options/samba]
>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> To unsubscribe from this list go to the following URL and read the
>>>>>>>> instructions:
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>>>>>>>
>>>>>>>
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