amd64/89202: Kernel crash when accessing filesystem

[Ivo Janssen]

The following reply was made to PR amd64/89202; it has been noted by GNATS.

From: Ivo Janssen <ivo at distributed.net>
To: bug-followup at FreeBSD.org
Cc:  
Subject: Re: amd64/89202: Kernel crash when accessing filesystem
Date: Thu, 17 Nov 2005 12:35:20 -0600 (CST)

 More information:
 
 In sys/ufs/ffs/ffs_alloc.c we find:
 
          dirsize = fs->fs_avgfilesize * fs->fs_avgfpdir
 
 dirsize is int, so it's an overflow
 our crash happened in a mkdir operation indeed
 
 our tunefs reports:
 > tunefs: average number of files in a directory: (-s)       64
 
 64 * 64 Mb == 2^32 
 So if a directory size can only be 4 gb, if we specify that the
 avg filesize is 64Mb and the avg number of files is 64, we overflow...