On Mon, 2012-09-03 at 20:35 +0200, Andi Kleen wrote: > Fix memset in nfs_zap_caches_locked > > This memset overruns the buffer by 4 bytes on 64bit systems. > > gcc 4.8 correct complains: > > /backup/lsrc/git/linux-lto-2.6/fs/nfs/inode.c: In function > 'nfs_zap_caches_locked': > /backup/lsrc/git/linux-lto-2.6/fs/nfs/inode.c:157:41: warning: argument > to 'sizeof' in 'memset' call is the same pointer type '__be32 *' as the > destination; expected '__be32' or an explicit length > [-Wsizeof-pointer-memaccess] > memset(NFS_COOKIEVERF(inode), 0, sizeof(NFS_COOKIEVERF(inode))); > ^ > Add a * to sizeof the correct type. > > Signed-off-by: Andi Kleen <a...@linux.intel.com> > > diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c > index c6e895f..69e7f0f 100644 > --- a/fs/nfs/inode.c > +++ b/fs/nfs/inode.c > @@ -154,7 +154,7 @@ static void nfs_zap_caches_locked(struct inode *inode) > nfsi->attrtimeo = NFS_MINATTRTIMEO(inode); > nfsi->attrtimeo_timestamp = jiffies; > > - memset(NFS_COOKIEVERF(inode), 0, sizeof(NFS_COOKIEVERF(inode))); > + memset(NFS_COOKIEVERF(inode), 0, sizeof(*NFS_COOKIEVERF(inode))); > if (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) > nfsi->cache_validity |= > NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA|NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL|NFS_INO_REVAL_PAGECACHE; > else
Hi Andi, No, this is a gcc bug. NFS_COOKIEVERF(inode) resolves to an array, so the current code is correct. The above change will cause the 2nd half of the array to remain uninitialised... Cheers Trond -- Trond Myklebust Linux NFS client maintainer NetApp trond.mykleb...@netapp.com www.netapp.com
