Re: [daisy][PATCH 1/1] systemd: do not use alloca() function in case of uclibc

[ChenQi <Qi.Chen@windriver.com>]

On 06/03/2014 05:20 PM, ChenQi wrote:
> On 06/03/2014 05:06 PM, Richard Purdie wrote:
>> On Tue, 2014-06-03 at 15:42 +0800, Chen Qi wrote:
>>> The alloca() function allocates space in the stack frame of the caller,
>>> so using alloca(new_size - old_size) would possibly crash the stack,
>>> causing a segment fault error.
>>>
>>> This patch fixes the above problem by avoiding using this function in
>>> journal-file.c.
>>>
>>> [YOCTO #6201]
>>>
>>> Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
>>> ---
>>>   .../0001-journal-file.c-do-not-use-alloca.patch    |   54 
>>> ++++++++++++++++++++
>>>   meta/recipes-core/systemd/systemd_211.bb           |    1 +
>>>   2 files changed, 55 insertions(+)
>>>   create mode 100644 
>>> meta/recipes-core/systemd/systemd/0001-journal-file.c-do-not-use-alloca.patch
>>>
>>> diff --git 
>>> a/meta/recipes-core/systemd/systemd/0001-journal-file.c-do-not-use-alloca.patch 
>>> b/meta/recipes-core/systemd/systemd/0001-journal-file.c-do-not-use-alloca.patch 
>>>
>>> new file mode 100644
>>> index 0000000..a638d58
>>> --- /dev/null
>>> +++ 
>>> b/meta/recipes-core/systemd/systemd/0001-journal-file.c-do-not-use-alloca.patch
>>> @@ -0,0 +1,54 @@
>>> +Upstream-Status: Inappropriate [oe specific]
>> >From the description, this sounds like an allocation error which can
>> happen *anywhere* and is a problem that should be addressed upstream.
>>
>> This Upstream-Status field is therefore completely bogus. Its not
>> inappropriate or oe specific. If you still believe it is, I'd like to
>> hear more explanation.
>>
>> The abuses of this field are starting to really annoy me since this
>> keeps happening.
>>
>> Cheers,
>>
>> Richard
>>
>>
>>
>>
>>
>
> Hi Richard,
>
> The use of alloca() was introduced by an oe-specific patch from Khem Raj.
>
> The patch is 
> meta/recipes-core/systemd/systemd/systemd-pam-fix-fallocate.patch.
> The upstream status of the above patch is as following.
>        Upstream-Status: Denied [no desire for uclibc support]
>
> That's why I use 'Inappropriate [oe specific]' in the Upstream-Status 
> field of my patch.
>
> And I just realized I forgot to also patch the journald-kmsg.c file. 
> I'll send out a V2.
>

Sorry for the confusion.

I just checked and  journald-kmsg.c doesn't have the same problem, as 
it's only allocating a small size of space.

      char *buf = alloca(sizeof(uint64_t));

So I think that's it.
I will also send out a patch for master branch.

Best Regards,
Chen Qi


> Best Regards,
> Chen Qi