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Date: Fri, 30 Mar 2007 08:50:21 +0200
From: Jan Kiszka <jan.kiszka@domain.hid>
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Subject: [Xenomai-core] Re: iovec overwriting by CAN stack
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To: Wolfgang Grandegger <wg@domain.hid>
Cc: xenomai-core <xenomai@xenomai.org>

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Wolfgang Grandegger wrote:
> Jan Kiszka wrote:
>> Hi Wolfgang,
>>
>> it's late, so I may have misread somecode, but don't you "update" the
>> iovec descriptors a user passes on send/recvmsg on return (namely
>> iovec_len)? I received some complaints about this /wrt to in-kernel CA=
N
>> stack usage.
>=20
> It's done here:
>=20
> http://www.rts.uni-hannover.de/xenomai/lxr/source/ksrc/drivers/can/rtca=
n_raw.c?v=3DSVN-trunk#881
>=20
> http://www.rts.uni-hannover.de/xenomai/lxr/source/ksrc/drivers/can/rtca=
n_raw.c?v=3DSVN-trunk#734
>=20
>=20
> I may have missed something. What are the real complaints? Is there a
> test program?

Not yet (will commit the related patch to our RACK likely later today).
It's simply sending frames while re-using the msg+iovec structs in a loop=
=2E

>=20
>> I always considered the same well-know behaviour of RTnet a bug, but n=
ow
>> I found your code is doing this systematically, also for user space
>> callers. Is this behaviour undefined or even required according POSIX =
or
>> whatever?
>=20
> I don't know, it's Sebastian's Kode.
>=20

Hmm, hope he will not say that he imitated RTnet...

Jan


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