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From: Dmitry Torokhov <dtor@vmware.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: pv-drivers@vmware.com, linux-kernel@vger.kernel.org,
	George Zhang <georgezhang@vmware.com>,
	virtualization@lists.linux-foundation.org
Subject: Re: [Pv-drivers] [PATCH 08/12] VMCI: resource object implementation.
Date: Mon, 29 Oct 2012 22:20:16 -0700	[thread overview]
Message-ID: <20121030052016.GF32055@dtor-ws.eng.vmware.com> (raw)
In-Reply-To: <20121030022905.GH1920@kroah.com>

On Mon, Oct 29, 2012 at 07:29:05PM -0700, Greg KH wrote:
> On Mon, Oct 29, 2012 at 06:04:58PM -0700, George Zhang wrote:
> > +static struct vmci_resource *vmci_resource_lookup(struct vmci_handle handle)
> > +{
> > +	struct vmci_resource *r, *resource = NULL;
> > +	struct hlist_node *node;
> > +	unsigned int idx = vmci_resource_hash(handle);
> > +
> > +	BUG_ON(VMCI_HANDLE_EQUAL(handle, VMCI_INVALID_HANDLE));
> 
> You just crashed a machine, with no chance for recovery.  Not a good
> idea.  Never a good idea.  Customers just lost data, and now they are
> mad.  Make sure you at least print out your email address so they know
> who to blame :)
> 
> Seriously, never BUG() in a driver, warn, sure, but this just looks like
> a debugging assert().  Please remove all of these, they are sprinkled
> all over the driver code here, I'm only responding to one of them here.
> 
> Even better yet, properly handle the error and keep on going, that's
> what the rest of the kernel does.  Or should :)

For public APIs it certainly makes sense to check and handle erroneous input;
internally it often makes sense to simply enforce invariants, because if
we managed to get into that state that we consider impossible we can't really
trust anything.

FWIW:
[dtor@dtor-ws kernel]$ grep -r BUG_ON . | wc -l
11269

Thanks,
Dmitry

  reply	other threads:[~2012-10-30  5:20 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-30  1:03 [PATCH 00/12] VMCI for Linux upstreaming George Zhang
2012-10-30  1:03 ` [PATCH 01/12] VMCI: context implementation George Zhang
2012-10-30  2:07   ` Greg KH
2012-10-30  2:10   ` Greg KH
2012-10-30  4:01     ` [Pv-drivers] " Dmitry Torokhov
2012-10-30 15:46       ` Greg KH
2012-10-30 15:56         ` Dmitry Torokhov
2012-10-30  1:03 ` [PATCH 02/12] VMCI: datagram implementation George Zhang
2012-10-30  1:04 ` [PATCH 03/12] VMCI: doorbell implementation George Zhang
2012-10-30  1:04 ` [PATCH 04/12] VMCI: device driver implementaton George Zhang
2012-10-30  2:21   ` Greg KH
2012-10-30  2:23   ` Greg KH
2012-10-30  4:15     ` [Pv-drivers] " Dmitry Torokhov
2012-10-30 15:49       ` Greg KH
2012-10-30  1:04 ` [PATCH 05/12] VMCI: event handling implementation George Zhang
2012-10-30  2:24   ` Greg KH
2012-10-30  4:58     ` [Pv-drivers] " Dmitry Torokhov
2012-10-30 15:50       ` Greg KH
2012-10-30  2:26   ` Greg KH
2012-10-30  5:01     ` [Pv-drivers] " Dmitry Torokhov
2012-10-30 15:50       ` Greg KH
2012-10-30 15:59         ` Dmitry Torokhov
2012-10-30  1:04 ` [PATCH 06/12] VMCI: handle array implementation George Zhang
2012-10-30  1:04 ` [PATCH 07/12] VMCI: queue pairs implementation George Zhang
2012-10-30  1:04 ` [PATCH 08/12] VMCI: resource object implementation George Zhang
2012-10-30  1:05 ` [PATCH 09/12] VMCI: routing implementation George Zhang
2012-10-30  1:05 ` [PATCH 10/12] VMCI: guest side driver implementation George Zhang
2012-10-30  1:05 ` [PATCH 11/12] VMCI: host " George Zhang
2012-10-30  1:05 ` [PATCH 12/12] VMCI: Some header and config files George Zhang
2012-10-30  2:32   ` Greg KH
2012-10-30  5:22     ` [Pv-drivers] " Dmitry Torokhov
2012-10-30  2:38   ` Greg KH
2012-10-30  2:19 ` [PATCH 00/12] VMCI for Linux upstreaming Greg KH
2012-10-30  4:07   ` [Pv-drivers] " Dmitry Torokhov
2012-10-30 15:48     ` Greg KH
2012-10-30 16:18       ` Dmitry Torokhov
2012-10-30 16:27         ` Greg KH
2012-10-30 19:43           ` Dmitry Torokhov
2012-10-30 19:59             ` Greg KH
     [not found] ` <20121030010453.17788.90295.stgit@promb-2n-dhcp175.eng.vmware.com>
2012-10-30  2:29   ` [PATCH 08/12] VMCI: resource object implementation Greg KH
2012-10-30  5:20     ` Dmitry Torokhov [this message]
2012-10-30 15:51       ` [Pv-drivers] " Greg KH
2012-10-30 16:11         ` Dmitry Torokhov
2012-10-30  2:29   ` Greg KH
2012-10-30  5:21     ` [Pv-drivers] " Dmitry Torokhov

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