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From: Jason Gunthorpe <jgg@nvidia.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: alsa-devel@alsa-project.org, Kiran Patil <kiran.patil@intel.com>,
	tiwai@suse.de, ranjani.sridharan@intel.com,
	pierre-louis.bossart@linux.intel.com,
	Ranjani Sridharan <ranjani.sridharan@linux.intel.com>,
	Fred Oh <fred.oh@linux.intel.com>,
	broonie@kernel.org, parav@nvidia.com,
	Dave Ertman <david.m.ertman@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Shiraz Saleem <shiraz.saleem@intel.com>,
	Parav Pandit <parav@mellanox.com>
Subject: Re: [PATCH 1/6] Add ancillary bus support
Date: Thu, 1 Oct 2020 08:46:08 -0300	[thread overview]
Message-ID: <20201001114608.GX816047@nvidia.com> (raw)
In-Reply-To: <20201001110120.GB1939744@kroah.com>

On Thu, Oct 01, 2020 at 01:01:20PM +0200, Greg KH wrote:
> On Wed, Sep 30, 2020 at 03:50:46PM -0700, Dave Ertman wrote:
> > +int ancillary_device_initialize(struct ancillary_device *ancildev)
> > +{
> > +	struct device *dev = &ancildev->dev;
> > +
> > +	dev->bus = &ancillary_bus_type;
> > +
> > +	if (WARN_ON(!dev->parent) || WARN_ON(!ancildev->name) ||
> > +	    WARN_ON(!(dev->type && dev->type->release) && !dev->release))
> > +		return -EINVAL;
> 
> You have a lot of WARN_ON() calls in this patch.  That blows up anyone
> who runs with panic-on-warn, right?

AFAIK this is the standard pattern to code a "can't happen"
assertion. Linus has been clear not to use BUG_ON, but to try and
recover. The WARN_ON directly points to the faulty driver so it can be
fixed. 

panic-on-warn is a good thing because it causes fuzzers to report a
"can't happen" condition as a failure.

In a real production system if any of these trigger it means the
kernel has detected an internal integrity problem (corrupted memory,
code, ROP attempt, etc). People using panic-on-warn absolutely want
their kernel to stop of it is not functioning properly to protect
data-integrity.

Jason

  reply	other threads:[~2020-10-01 13:48 UTC|newest]

Thread overview: 99+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-30 22:50 [PATCH 0/6] Ancillary bus implementation and SOF multi-client support Dave Ertman
2020-09-30 22:50 ` [PATCH 1/6] Add ancillary bus support Dave Ertman
2020-09-30 23:05   ` Jason Gunthorpe
2020-10-01 11:01   ` Greg KH
2020-10-01 11:46     ` Jason Gunthorpe [this message]
2020-10-01 11:54       ` Greg KH
2020-10-01 12:02         ` Jason Gunthorpe
2020-10-01 12:15           ` Greg KH
2020-10-01 18:26             ` Ertman, David M
2020-10-01 11:02   ` Greg KH
2020-10-01 16:30     ` Ertman, David M
2020-10-01 11:05   ` Greg KH
2020-10-01 11:58     ` Jason Gunthorpe
2020-10-01 12:14       ` Greg KH
2020-10-01 14:33         ` Jason Gunthorpe
2020-10-01 14:38           ` Greg KH
2020-10-01 16:06             ` Pierre-Louis Bossart
2020-10-01 17:42             ` Jason Gunthorpe
2020-10-01 14:39           ` Parav Pandit
2020-10-01 14:43             ` Greg KH
2020-10-01 13:27   ` Mark Brown
2020-09-30 22:50 ` [PATCH 2/6] ASoC: SOF: Introduce descriptors for SOF client Dave Ertman
2020-10-01 13:02   ` Greg KH
2020-10-01 15:59     ` Sridharan, Ranjani
2020-10-01 22:16     ` Sridharan, Ranjani
2020-10-02  4:53       ` gregkh
2020-10-02 17:07         ` Sridharan, Ranjani
2020-10-03  9:02           ` gregkh
2020-10-05  2:35             ` Sridharan, Ranjani
2020-10-05 11:27               ` gregkh
2020-10-05 15:18                 ` Pierre-Louis Bossart
2020-10-05 15:32                   ` gregkh
2020-10-01 13:38   ` Mark Brown
2020-10-01 16:48     ` Sridharan, Ranjani
2020-09-30 22:50 ` [PATCH 3/6] ASoC: SOF: Create client driver for IPC test Dave Ertman
2020-10-01 13:04   ` Greg KH
2020-10-01 16:46     ` Sridharan, Ranjani
2020-10-01 13:09   ` Greg KH
2020-10-01 13:55     ` Pierre-Louis Bossart
2020-10-01 16:48       ` Ertman, David M
2020-10-01 13:59   ` Mark Brown
2020-09-30 22:50 ` [PATCH 4/6] ASoC: SOF: ops: Add ops for client registration Dave Ertman
2020-09-30 22:50 ` [PATCH 5/6] ASoC: SOF: Intel: Define " Dave Ertman
2020-09-30 22:50 ` [PATCH 6/6] ASoC: SOF: debug: Remove IPC flood test support in SOF core Dave Ertman
2020-10-01  5:58 ` [PATCH 0/6] Ancillary bus implementation and SOF multi-client support Greg KH
2020-10-01 15:54   ` Ertman, David M
2020-10-01  7:14 ` Greg KH
2020-10-01 15:55   ` Ertman, David M
2020-10-01 16:10     ` Greg KH
2020-10-01 17:13       ` Ertman, David M
2020-10-02 20:23   ` Ertman, David M
2020-10-03  9:08     ` Greg KH
2020-10-03  9:09       ` Greg KH
2020-10-04  2:26       ` Parav Pandit
2020-10-04 23:45       ` Williams, Dan J
2020-10-05  1:18         ` Ertman, David M
2020-10-05  2:39           ` Parav Pandit
2020-10-05 11:25         ` gregkh
2020-10-06 22:40           ` Dan Williams
2020-10-07  9:14             ` gregkh
2020-10-07 16:19               ` Dan Williams
2020-10-07 16:22                 ` Mark Brown
2020-10-07 16:41                   ` Dan Williams
2020-10-07 16:42                   ` Pierre-Louis Bossart
2020-10-07 16:56                     ` Parav Pandit
2020-10-01 10:05 ` Rojewski, Cezary
2020-10-01 10:59   ` gregkh
2020-10-01 12:49     ` Jason Gunthorpe
2020-10-01 12:55       ` gregkh
2020-10-01 13:26         ` Jason Gunthorpe
2020-10-01 14:17           ` gregkh
2020-10-01 15:08         ` Parav Pandit
2020-10-01 12:50 ` Mark Brown
2020-10-01 13:12   ` Greg KH
2020-10-01 13:42     ` Jason Gunthorpe
2020-10-01 14:40     ` Mark Brown
2020-10-01 15:32       ` Greg KH
2020-10-01 16:03         ` Mark Brown
2020-10-01 18:16           ` Greg KH
2020-10-01 18:29             ` Ertman, David M
2020-10-01 19:38               ` Mark Brown
2020-10-01 19:54                 ` Ertman, David M
2020-10-01 20:17                   ` Mark Brown
2020-10-02  0:47                     ` Jason Gunthorpe
2020-10-02 11:19                       ` Mark Brown
2020-10-02 17:23                         ` Ertman, David M
2020-10-02 17:25                           ` Jason Gunthorpe
2020-10-02 17:44                             ` Mark Brown
2020-10-01 14:07   ` Pierre-Louis Bossart
2020-10-01 15:24     ` Mark Brown
2020-10-01 16:20       ` Pierre-Louis Bossart
2020-10-01 16:51         ` Mark Brown
2020-10-01 18:04           ` Jason Gunthorpe
2020-10-01 18:13             ` Greg KH
2020-10-01 19:23             ` Mark Brown
2020-10-01 16:50     ` Ertman, David M
2020-10-01 17:10       ` Mark Brown
2020-10-01 17:16         ` Ertman, David M
2020-10-01 17:52 ` Ertman, David M

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