From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>,
linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org,
linux-doc@vger.kernel.org, Alexander Graf <agraf@suse.de>,
kvm-ppc@vger.kernel.org, linux-kernel@vger.kernel.org,
Alex Williamson <alex.williamson@redhat.com>,
Paul Mackerras <paulus@samba.org>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [PATCH 3/8] vfio: add external user support
Date: Thu, 27 Jun 2013 09:42:46 +0000 [thread overview]
Message-ID: <1372326166.18612.42.camel@pasglop> (raw)
In-Reply-To: <20130627165929.3828c261c957845a549ad95b@canb.auug.org.au>
On Thu, 2013-06-27 at 16:59 +1000, Stephen Rothwell wrote:
> > +/* Allows an external user (for example, KVM) to unlock an IOMMU
> group */
> > +static void vfio_group_del_external_user(struct file *filep)
> > +{
> > + struct vfio_group *group = filep->private_data;
> > +
> > + BUG_ON(filep->f_op != &vfio_group_fops);
>
> We usually reserve BUG_ON for situations where there is no way to
> continue running or continuing will corrupt the running kernel. Maybe
> WARN_ON() and return?
Not even that. This is a user space provided "fd", we shouldn't oops the
kernel because we passed a wrong argument, just return -EINVAL or
something like that (add a return code).
Ben.
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: kvm@vger.kernel.org, linux-doc@vger.kernel.org,
Alexey Kardashevskiy <aik@ozlabs.ru>,
Alexander Graf <agraf@suse.de>,
kvm-ppc@vger.kernel.org, linux-kernel@vger.kernel.org,
Alex Williamson <alex.williamson@redhat.com>,
Paul Mackerras <paulus@samba.org>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org,
David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [PATCH 3/8] vfio: add external user support
Date: Thu, 27 Jun 2013 19:42:46 +1000 [thread overview]
Message-ID: <1372326166.18612.42.camel@pasglop> (raw)
In-Reply-To: <20130627165929.3828c261c957845a549ad95b@canb.auug.org.au>
On Thu, 2013-06-27 at 16:59 +1000, Stephen Rothwell wrote:
> > +/* Allows an external user (for example, KVM) to unlock an IOMMU
> group */
> > +static void vfio_group_del_external_user(struct file *filep)
> > +{
> > + struct vfio_group *group = filep->private_data;
> > +
> > + BUG_ON(filep->f_op != &vfio_group_fops);
>
> We usually reserve BUG_ON for situations where there is no way to
> continue running or continuing will corrupt the running kernel. Maybe
> WARN_ON() and return?
Not even that. This is a user space provided "fd", we shouldn't oops the
kernel because we passed a wrong argument, just return -EINVAL or
something like that (add a return code).
Ben.
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>,
linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org,
linux-doc@vger.kernel.org, Alexander Graf <agraf@suse.de>,
kvm-ppc@vger.kernel.org, linux-kernel@vger.kernel.org,
Alex Williamson <alex.williamson@redhat.com>,
Paul Mackerras <paulus@samba.org>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [PATCH 3/8] vfio: add external user support
Date: Thu, 27 Jun 2013 19:42:46 +1000 [thread overview]
Message-ID: <1372326166.18612.42.camel@pasglop> (raw)
In-Reply-To: <20130627165929.3828c261c957845a549ad95b@canb.auug.org.au>
On Thu, 2013-06-27 at 16:59 +1000, Stephen Rothwell wrote:
> > +/* Allows an external user (for example, KVM) to unlock an IOMMU
> group */
> > +static void vfio_group_del_external_user(struct file *filep)
> > +{
> > + struct vfio_group *group = filep->private_data;
> > +
> > + BUG_ON(filep->f_op != &vfio_group_fops);
>
> We usually reserve BUG_ON for situations where there is no way to
> continue running or continuing will corrupt the running kernel. Maybe
> WARN_ON() and return?
Not even that. This is a user space provided "fd", we shouldn't oops the
kernel because we passed a wrong argument, just return -EINVAL or
something like that (add a return code).
Ben.
next prev parent reply other threads:[~2013-06-27 9:42 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-27 5:02 [PATCH 0/8 v4] KVM: PPC: IOMMU in-kernel handling Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 5:02 ` [PATCH 1/8] KVM: PPC: reserve a capability number for multitce support Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 5:02 ` [PATCH 2/8] KVM: PPC: reserve a capability and ioctl numbers for realmode VFIO Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-07-09 15:35 ` Alexander Graf
2013-07-09 15:35 ` Alexander Graf
2013-07-09 15:35 ` Alexander Graf
2013-07-09 23:35 ` Alexey Kardashevskiy
2013-07-09 23:35 ` Alexey Kardashevskiy
2013-07-09 23:35 ` Alexey Kardashevskiy
2013-07-10 10:27 ` Alexander Graf
2013-07-10 10:27 ` Alexander Graf
2013-07-10 10:27 ` Alexander Graf
2013-07-10 14:17 ` Alexey Kardashevskiy
2013-07-10 14:17 ` Alexey Kardashevskiy
2013-07-10 14:17 ` Alexey Kardashevskiy
2013-07-10 15:00 ` Alexander Graf
2013-07-10 15:00 ` Alexander Graf
2013-07-10 15:00 ` Alexander Graf
2013-06-27 5:02 ` [PATCH 3/8] vfio: add external user support Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 6:47 ` Stephen Rothwell
2013-06-27 6:47 ` Stephen Rothwell
2013-06-27 6:47 ` Stephen Rothwell
2013-06-27 7:14 ` [PATCH v2] " Alexey Kardashevskiy
2013-06-27 7:14 ` Alexey Kardashevskiy
2013-06-27 7:50 ` Stephen Rothwell
2013-06-27 15:44 ` Alex Williamson
2013-06-27 15:44 ` Alex Williamson
2013-06-27 22:57 ` Alexey Kardashevskiy
2013-06-27 22:57 ` Alexey Kardashevskiy
2013-06-28 0:41 ` Alex Williamson
2013-06-28 0:41 ` Alex Williamson
2013-06-28 1:38 ` Alexey Kardashevskiy
2013-06-28 1:38 ` Alexey Kardashevskiy
2013-06-28 2:37 ` Alex Williamson
2013-06-28 2:37 ` Alex Williamson
2013-06-28 3:10 ` Alexey Kardashevskiy
2013-06-28 3:10 ` Alexey Kardashevskiy
2013-06-27 6:59 ` [PATCH 3/8] " Stephen Rothwell
2013-06-27 6:59 ` Stephen Rothwell
2013-06-27 6:59 ` Stephen Rothwell
2013-06-27 9:42 ` Benjamin Herrenschmidt [this message]
2013-06-27 9:42 ` Benjamin Herrenschmidt
2013-06-27 9:42 ` Benjamin Herrenschmidt
2013-06-27 10:48 ` Alexey Kardashevskiy
2013-06-27 10:48 ` Alexey Kardashevskiy
2013-06-27 10:48 ` Alexey Kardashevskiy
2013-06-27 5:02 ` [PATCH 4/8] hashtable: add hash_for_each_possible_rcu_notrace() Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 5:02 ` [PATCH 5/8] powerpc: Prepare to support kernel handling of IOMMU map/unmap Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 5:02 ` [PATCH 6/8] KVM: PPC: Add support for multiple-TCE hcalls Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 5:02 ` [PATCH 7/8] KVM: PPC: Add support for IOMMU in-kernel handling Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 5:02 ` [PATCH 8/8] KVM: PPC: Add hugepage " Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 5:02 ` Alexey Kardashevskiy
2013-06-27 18:39 ` Scott Wood
2013-06-27 18:39 ` Scott Wood
2013-06-27 18:39 ` Scott Wood
-- strict thread matches above, loose matches on Subject: below --
2013-07-06 15:06 [PATCH 0/8 v5] KVM: PPC: " Alexey Kardashevskiy
2013-07-06 15:07 ` [PATCH 3/8] vfio: add external user support Alexey Kardashevskiy
2013-07-06 15:07 ` Alexey Kardashevskiy
2013-07-06 15:07 ` Alexey Kardashevskiy
2013-07-08 21:52 ` Alex Williamson
2013-07-08 21:52 ` Alex Williamson
2013-07-08 21:52 ` Alex Williamson
2013-07-09 5:40 ` Alexey Kardashevskiy
2013-07-09 5:40 ` Alexey Kardashevskiy
2013-07-09 5:40 ` Alexey Kardashevskiy
2013-07-09 14:08 ` Alex Williamson
2013-07-09 14:08 ` Alex Williamson
2013-07-09 14:08 ` Alex Williamson
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