From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <44589714.10800@domain.hid> Date: Wed, 03 May 2006 13:42:12 +0200 From: Jan Kiszka MIME-Version: 1.0 Subject: Re: [Xenomai-help] Buffer Overrun -> Kernel Explosion References: <6ee4c8380604272202q3109a3b9n71e0327de76730b8@domain.hid> In-Reply-To: <6ee4c8380604272202q3109a3b9n71e0327de76730b8@domain.hid> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig3372C2140C4E38DA85BCA4B5" Sender: jan.kiszka@domain.hid List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Brian L." Cc: xenomai@xenomai.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig3372C2140C4E38DA85BCA4B5 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable Brian L. wrote: > I'm finally set up with netconsole to catch panics/crashes when they > happen so now I can report more information on the one I alluded to a > week or two ago in my "General Question.." thread. >=20 > What I did to cause it was write past the end of a buffer returned by > rt_queue_alloc. I'm not entirely sure if this message came at the > moment of the write (unlikely, IMHO) or later when more xnheap > activity took place. The crash popped up in several different ways > depending on what code paths I enabled/disabled. >=20 > What concerns me is that polluting an xnheap can bring the system to > its knees so harshly. I can see why it could be *very* hard to police > this sort of problem without destroying the performance of xnheap, so > it wouldn't surprise me if this is "normal". Still, though, it's sad > that user-space code can bring the system down after something as > innocent as a fencepost error in a string copy routine... >=20 > Thoughts? I've pasted the console dump below. >=20 I remember that control structures and data are tightly knotted in xnheaps, but I agree with you that this should not lead so easily to such crashes for user space apps. Maybe some magic number check could help to reduce the chance for now. A cleaner long-term solution would be to decouple both regions. Philippe, is this feasible (I'm not that deep in the internals of xnheap)= ? Jan --------------enig3372C2140C4E38DA85BCA4B5 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFEWJcUniDOoMHTA+kRAnXcAJ98+3mI5WU3avhHf/a1nXPDEizp6ACdEo6j p/9OMAnmiMMT9awEm9+VUn0= =POg6 -----END PGP SIGNATURE----- --------------enig3372C2140C4E38DA85BCA4B5--