Re: [PATCH V2 04/12] virtio_console: validate max_nr_ports before trying to use it

From: kernel test robot <lkp@intel.com>
To: kbuild@lists.01.org
Subject: Re: [PATCH V2 04/12] virtio_console: validate max_nr_ports before trying to use it
Date: Wed, 13 Oct 2021 05:09:14 +0800	[thread overview]
Message-ID: <202110130542.zmHunyOJ-lkp@intel.com> (raw)

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CC: kbuild-all(a)lists.01.org
In-Reply-To: <20211012065227.9953-5-jasowang@redhat.com>
References: <20211012065227.9953-5-jasowang@redhat.com>
TO: Jason Wang <jasowang@redhat.com>
TO: mst(a)redhat.com
TO: jasowang(a)redhat.com
CC: virtualization(a)lists.linux-foundation.org
CC: linux-kernel(a)vger.kernel.org
CC: f.hetzelt(a)tu-berlin.de
CC: david.kaplan(a)amd.com
CC: konrad.wilk(a)oracle.com
CC: Amit Shah <amit@kernel.org>

Hi Jason,

I love your patch! Perhaps something to improve:

[auto build test WARNING on axboe-block/for-next]
[also build test WARNING on char-misc/char-misc-testing mst-vhost/linux-next linus/master v5.15-rc5 next-20211012]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Jason-Wang/More-virtio-hardening/20211012-145541
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
:::::: branch date: 14 hours ago
:::::: commit date: 14 hours ago
config: x86_64-randconfig-m001-20211012 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

New smatch warnings:
drivers/char/virtio_console.c:2008 virtcons_validate() error: uninitialized symbol 'max_nr_ports'.

Old smatch warnings:
drivers/char/virtio_console.c:1604 handle_control_message() error: we previously assumed 'port' could be null (see line 1572)

vim +/max_nr_ports +2008 drivers/char/virtio_console.c

aa44ec867030a72 Michael S. Tsirkin 2018-04-20  1982  
83d05ea1530de43 Jason Wang         2021-10-12  1983  static int virtcons_validate(struct virtio_device *vdev)
83d05ea1530de43 Jason Wang         2021-10-12  1984  {
96703132f927fa0 Jason Wang         2021-10-12  1985  	u32 max_nr_ports;
96703132f927fa0 Jason Wang         2021-10-12  1986  
83d05ea1530de43 Jason Wang         2021-10-12  1987  	if (is_rproc_serial(vdev)) {
83d05ea1530de43 Jason Wang         2021-10-12  1988  		/* Don't test F_SIZE at all if we're rproc: not a
83d05ea1530de43 Jason Wang         2021-10-12  1989  		 * valid feature! */
83d05ea1530de43 Jason Wang         2021-10-12  1990  		__virtio_clear_bit(vdev, VIRTIO_CONSOLE_F_SIZE);
83d05ea1530de43 Jason Wang         2021-10-12  1991  		/* Don't test MULTIPORT at all if we're rproc: not a
83d05ea1530de43 Jason Wang         2021-10-12  1992  		 * valid feature! */
83d05ea1530de43 Jason Wang         2021-10-12  1993  		__virtio_clear_bit(vdev, VIRTIO_CONSOLE_F_MULTIPORT);
83d05ea1530de43 Jason Wang         2021-10-12  1994  	}
83d05ea1530de43 Jason Wang         2021-10-12  1995  
83d05ea1530de43 Jason Wang         2021-10-12  1996  	/* We only need a config space if features are offered */
83d05ea1530de43 Jason Wang         2021-10-12  1997  	if (!vdev->config->get &&
83d05ea1530de43 Jason Wang         2021-10-12  1998  	    (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)
83d05ea1530de43 Jason Wang         2021-10-12  1999  	     || virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT))) {
83d05ea1530de43 Jason Wang         2021-10-12  2000  		dev_err(&vdev->dev, "%s failure: config access disabled\n",
83d05ea1530de43 Jason Wang         2021-10-12  2001  			__func__);
83d05ea1530de43 Jason Wang         2021-10-12  2002  		return -EINVAL;
83d05ea1530de43 Jason Wang         2021-10-12  2003  	}
83d05ea1530de43 Jason Wang         2021-10-12  2004  
96703132f927fa0 Jason Wang         2021-10-12  2005  	if (virtio_cread_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
96703132f927fa0 Jason Wang         2021-10-12  2006  				 struct virtio_console_config, max_nr_ports,
96703132f927fa0 Jason Wang         2021-10-12  2007  				 &max_nr_ports) == 0) {
96703132f927fa0 Jason Wang         2021-10-12 @2008  		if (max_nr_ports == 0 || max_nr_ports > VIRTCONS_MAX_PORTS)
96703132f927fa0 Jason Wang         2021-10-12  2009  			__virtio_clear_bit(vdev, VIRTIO_CONSOLE_F_MULTIPORT);
96703132f927fa0 Jason Wang         2021-10-12  2010  	}
96703132f927fa0 Jason Wang         2021-10-12  2011  
83d05ea1530de43 Jason Wang         2021-10-12  2012  	return 0;
83d05ea1530de43 Jason Wang         2021-10-12  2013  }
83d05ea1530de43 Jason Wang         2021-10-12  2014  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

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