From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dan Carpenter <dan.carpenter@oracle.com>
Subject: smatch stuff: potential NULL dereference in btrfs_rm_device()
Date: Tue, 8 Nov 2011 17:59:45 +0300
Message-ID: <20111108145944.GA30841@elgon.mountain>
Mime-Version: 1.0
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Cc: linux-btrfs@vger.kernel.org
To: Yan Zheng <zheng.yan@oracle.com>
Return-path: <linux-btrfs-owner@vger.kernel.org>
List-ID: <linux-btrfs.vger.kernel.org>

Hi Yan,

Smatch complains about this code from 2008.

fs/btrfs/volumes.c +1417 btrfs_rm_device(157)
	error: we previously assumed 'fs_devices' could be null (see line 1412)

  1412                  while (fs_devices) {
                               ^^^^^^^^^^
checked here.

  1413                          if (fs_devices->seed == cur_devices)
  1414                                  break;
  1415                          fs_devices = fs_devices->seed;
  1416                  }
  1417                  fs_devices->seed = cur_devices->seed;
                        ^^^^^^^^^^^^
dereferenced here.

If we don't hit the break statement, then at the end of the loop we'd
oops.

regards,
dan carpenter