Date: Wed, 3 Sep 2014 11:47:07 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Gleb Smirnoff <glebius@FreeBSD.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r270999 - head/sys/kern Message-ID: <20140903084707.GH2737@kib.kiev.ua> In-Reply-To: <201409030814.s838E7A2084257@svn.freebsd.org> References: <201409030814.s838E7A2084257@svn.freebsd.org>
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--wfk8K8yAAOQoLncY Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Sep 03, 2014 at 08:14:07AM +0000, Gleb Smirnoff wrote: > Author: glebius > Date: Wed Sep 3 08:14:07 2014 > New Revision: 270999 > URL: http://svnweb.freebsd.org/changeset/base/270999 >=20 > Log: > Fix dereference after NULL check. > =20 > CID: 1234607 > Sponsored by: Nginx, Inc. >=20 > Modified: > head/sys/kern/kern_proc.c >=20 > Modified: head/sys/kern/kern_proc.c > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D > --- head/sys/kern/kern_proc.c Wed Sep 3 08:13:46 2014 (r270998) > +++ head/sys/kern/kern_proc.c Wed Sep 3 08:14:07 2014 (r270999) > @@ -921,10 +921,11 @@ fill_kinfo_proc_only(struct proc *p, str > kp->ki_xstat =3D p->p_xstat; > kp->ki_acflag =3D p->p_acflag; > kp->ki_lock =3D p->p_lock; > - if (p->p_pptr) > + if (p->p_pptr) { > kp->ki_ppid =3D proc_realparent(p)->p_pid; > - if (p->p_flag & P_TRACED) > - kp->ki_tracer =3D p->p_pptr->p_pid; > + if (p->p_flag & P_TRACED) > + kp->ki_tracer =3D p->p_pptr->p_pid; > + } > } If P_TRACED is set, p_pptr must be non-NULL. Or in reverse, only kernel process (pid 0) may have p_pptr as NULL, and it cannot be traced. Previous code contained assertion (triggered by paging hardware) that p_pptr is not NULL if P_TRACED is set. It is Coverity which cannot deduce the invariant. I do not expect any analyzer to be able to make the implication, though. --wfk8K8yAAOQoLncY Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJUBtWLAAoJEJDCuSvBvK1BEpQP/RYW3XUszfAXBpDM7cojLBUR EAqN90D5uDWvBmDzjqQof804RfgV9hCNshBol9mzIlUQxxRvQo+006LTQ73Mc0aK XTOeALw49fh4AV3BdG54cnUeVpDgpzz2iojU5C+bPf2kzYDaLJDgNd10FyIsyRGR 5d2soMOA+rAW5m9SVPNnwVsZdRX8/dXsX9gESIqF2bT71Kfl7aURxFdE6qDCYtr8 oHaT4Qf3HlzzIj+eaSPRgqs6Te11NsD8h3VluSQyX3SDcRGPfIc3oYJg+MDsfTZq pRxDAqym1n0aD5UUu32sk93XUEt9hl1BVa4YstcCq5+8PBuCmd3Pker5sSiEOQwd 4s6knIjCM8QOukXUX00sn+iCIFYlFSFTOlbXhXc112gYbDO1nLOBPoI3Y4US4yuC UJlSOd9eQvPYvZtzx6/NIXNnWUUFc9qeU2TLXkjmSerd5lNTWt57Ix56EcZH8kPW j/1avXWU+vIaysxKnhZRwWpztJ6g1k25qQufBJmQHmqF0CR84YsUQ7Piz3ImP5j6 9wkXX0PY89bohmVsqzNftOBF4HpxZrKpQVK5gd/l7ujZ2bhTWLzEqOo+vwLgmM7H wQwaR0A8NE3Je528Mmme1TpzN6ZPgQ1d9Ge0K7MW8q8rj5BOvmvEDMCv5caI4yKn aV5rPuq4zKLVDbSlhmwG =HzmX -----END PGP SIGNATURE----- --wfk8K8yAAOQoLncY--
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