Date: Tue, 12 Aug 2008 16:15:21 +0200 From: Ed Schouten <ed@80386.nl> To: Bruce Evans <brde@optusnet.com.au> Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org, John Baldwin <jhb@FreeBSD.org> Subject: Re: cvs commit: src/sys/dev/io iodev.c Message-ID: <20080812141521.GX99951@hoeg.nl> In-Reply-To: <20080812231130.D760@besplex.bde.org> References: <200808081343.m78DhwYE068477@repoman.freebsd.org> <200808081226.32089.jhb@freebsd.org> <20080809130929.P77335@delplex.bde.org> <200808091555.25020.jhb@freebsd.org> <20080812014937.E21092@besplex.bde.org> <20080812231130.D760@besplex.bde.org>
next in thread | previous in thread | raw e-mail | index | archive | help
--+jMesTDEFHiw5APJ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hello all, * Bruce Evans <brde@optusnet.com.au> wrote: > I checked that bpf panics (even under UP) due to the obvious bugs in > its d_close(): > > # Generate lots of network activity using something like: > sysctl net.inet.icmp.icmplim=3D0; ping -fq localhost & > > # Race to panic eventually: > while :; do tcpdump -i lo0 & sleep 0.001; revoke /dev/bpf0 > > Most or all device drivers have obvious bugs in their d_close(); bpf > is just a bit easier to understand and more likely to cause a panic > than most device drivers, since it is simple and frees resources. A > panic is very likely when si_drv1 is freed, and si_drv1 is only locked > accidentally. I remember I once warned people about this on the lists. It seems the cdevpriv API is protected against this, so the following patch turns BPF into a single device node, which can handle revoke() calls properly. I wrote this patch a month ago, but eventually I didn't commit this. I think I should, though. http://80386.nl/files/bpf-cdevpriv.diff --=20 Ed Schouten <ed@80386.nl> WWW: http://80386.nl/ --+jMesTDEFHiw5APJ Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (FreeBSD) iEYEARECAAYFAkihmvkACgkQ52SDGA2eCwWu2ACfckbk96dVdjzuZNczNyaZu24J EqMAn1nGCe9ffbEb+MGjHo83TTzgTwYZ =CeAw -----END PGP SIGNATURE----- --+jMesTDEFHiw5APJ--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20080812141521.GX99951>