On 2011-05-24 12:41, Gilles Chanteperdrix wrote:
> On 05/24/2011 12:36 PM, Jan Kiszka wrote:
>> On 2011-05-24 11:58, Gilles Chanteperdrix wrote:
>>> On 05/24/2011 11:36 AM, Jan Kiszka wrote:
>>>> On 2011-05-24 11:32, Gilles Chanteperdrix wrote:
>>>>> On 05/24/2011 11:13 AM, Jan Kiszka wrote:
>>>>>> On 2011-05-24 06:31, Gilles Chanteperdrix wrote:
>>>>>>> On 05/23/2011 03:53 PM, Jan Kiszka wrote:
>>>>>>>> The following changes since commit
>>>>>>>> aec30a2543afa18fa7832deee85e187b0faeb1f0:
>>>>>>>>
>>>>>>>> xeno-test: fix reference to @XENO_TEST_DIR@ (2011-05-15 21:20:41
>>>>>>>> +0200)
>>>>>>>>
>>>>>>>> are available in the git repository at:
>>>>>>>> git://git.xenomai.org/xenomai-jki.git for-upstream
>>>>>>>>
>>>>>>>> Jan Kiszka (1):
>>>>>>>> native: Fix msendq fastlock leakage
>>>>>>>>
>>>>>>>> include/native/task.h | 5 +++++
>>>>>>>> ksrc/skins/native/task.c | 13 ++++++-------
>>>>>>>> 2 files changed, 11 insertions(+), 7 deletions(-)
>>>>>>>>
>>>>>>>> ------8<------
>>>>>>>>
>>>>>>>> When a native task terminates without going through rt_task_delete, we
>>>>>>>> leaked the fastlock so far. Fix it by moving the release into the
>>>>>>>> delete
>>>>>>>> hook. As the ppd is already invalid at that point, we have to save the
>>>>>>>> heap address in the task data structure.
>>>>>>>
>>>>>>> I Jan, I once worked on a patch to reverse the ppd cleanup order, in
>>>>>>> order
>>>>>>> to fix bugs of this kind. Here it comes. I do not remember why I did not
>>>>>>> commit it, but I guess it was not working well. Could we restart working
>>>>>>> from this patch?
>>>>>>>
>>>>>>> From 038ecf08cd66b3112e0fe277d71d294b8eb83bcc Mon Sep 17 00:00:00 2001
>>>>>>> From: Gilles Chanteperdrix <gilles.chanteperd...@xenomai.org>
>>>>>>> Date: Sun, 29 Aug 2010 14:52:08 +0200
>>>>>>> Subject: [PATCH] nucleus: reverse ppd cleanup order
>>>>>>>
>>>>>>> ---
>>>>>>> ksrc/nucleus/shadow.c | 11 ++++++-----
>>>>>>> 1 files changed, 6 insertions(+), 5 deletions(-)
>>>>>>>
>>>>>>> diff --git a/ksrc/nucleus/shadow.c b/ksrc/nucleus/shadow.c
>>>>>>> index b2d4326..725ae43 100644
>>>>>>> --- a/ksrc/nucleus/shadow.c
>>>>>>> +++ b/ksrc/nucleus/shadow.c
>>>>>>> @@ -556,7 +556,7 @@ static unsigned ppd_lookup_inner(xnqueue_t **pq,
>>>>>>> }
>>>>>>> while (holder &&
>>>>>>> (ppd->key.mm < pkey->mm ||
>>>>>>> - (ppd->key.mm == pkey->mm && ppd->key.muxid <
>>>>>>> pkey->muxid)));
>>>>>>> + (ppd->key.mm == pkey->mm && ppd->key.muxid >
>>>>>>> pkey->muxid)));
>>>>>>>
>>>>>>> if (ppd->key.mm == pkey->mm && ppd->key.muxid == pkey->muxid) {
>>>>>>> /* found it, return it. */
>>>>>>> @@ -566,7 +566,7 @@ static unsigned ppd_lookup_inner(xnqueue_t **pq,
>>>>>>>
>>>>>>> /* not found, return successor for insertion. */
>>>>>>> if (ppd->key.mm < pkey->mm ||
>>>>>>> - (ppd->key.mm == pkey->mm && ppd->key.muxid < pkey->muxid))
>>>>>>> + (ppd->key.mm == pkey->mm && ppd->key.muxid > pkey->muxid))
>>>>>>> *pholder = holder ? link2ppd(holder) : NULL;
>>>>>>> else
>>>>>>> *pholder = ppd;
>>>>>>> @@ -589,10 +589,11 @@ static int ppd_insert(xnshadow_ppd_t * holder)
>>>>>>> }
>>>>>>>
>>>>>>> inith(&holder->link);
>>>>>>> - if (next)
>>>>>>> + if (next) {
>>>>>>> insertq(q, &next->link, &holder->link);
>>>>>>> - else
>>>>>>> + } else {
>>>>>>> appendq(q, &holder->link);
>>>>>>> + }
>>>>>>> xnlock_put_irqrestore(&nklock, s);
>>>>>>>
>>>>>>> return 0;
>>>>>>> @@ -640,7 +641,7 @@ static inline void ppd_remove_mm(struct mm_struct
>>>>>>> *mm,
>>>>>>> xnqueue_t *q;
>>>>>>> spl_t s;
>>>>>>>
>>>>>>> - key.muxid = 0;
>>>>>>> + key.muxid = ~0UL;
>>>>>>> key.mm = mm;
>>>>>>> xnlock_get_irqsave(&nklock, s);
>>>>>>> ppd_lookup_inner(&q, &ppd, &key);
>>>>>>
>>>>>> Unfortunately, that won't help. I think we are forced to clear
>>>>>> xnshadow_thrptd before calling into xnpod_delete_thread, but we would
>>>>>> need that for xnshadow_ppd_get (=>xnpod_userspace_p()).
>>>>>
>>>>> I remember that now. Even if it worked, when the cleanup handler is
>>>>> called, current->mm is NULL. We need to do this differently, the sys ppd
>>>>> should be treated differently and passed to the other ppds cleanup
>>>>> routines.
>>>>
>>>> Do you already have an idea how to get that info to the delete hook
>>>> function?
>>>
>>> Yes. We start by not applying the list reversal patch, then the sys_ppd
>>> is the first in the list. So, we can, in the function ppd_remove_mm,
>>> start by removing all the others ppd, then remove the sys ppd (that is
>>> the first), last. This changes a few signatures in the core code, a lot
>>> of things in the skin code, but that would be for the better...
>>
>> I still don't see how this affects the order we use in
>> do_taskexit_event, the one that prevents xnsys_get_ppd usage even when
>> the mm is still present.
>
> The idea is to change the cleanup routines not to call xnsys_get_ppd.
...and use what instead? Sorry, I'm slow today.
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
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