Hi, On Wed, 2012-07-04 at 17:32 +0800, Robin Dong wrote: > From: Robin Dong <sanbai@xxxxxxxxxx> > > When we using lookup_one_len() to search pathname component, it will call __lookup_hash() > with variable 'nd' as NULL : > > --> __lookup_hash ( nd = NULL ) > --> lookup_dcache > --> d_invalidate > --> proc_sys_revalidate > > the proc_sys_revalidate will use 'nd->flags' before check whether its value is NULL. > This will cause kernel panic. > > Therefore, we should adding check-code for filesystems which directly use nd->flags. > > Signed-off-by: Robin Dong <sanbai@xxxxxxxxxx> nd will very shortly no longer be passed to revalidate... see this patch in Al's vfs git tree: http://git.kernel.org/?p=linux/kernel/git/viro/vfs.git;a=commitdiff;h=282638cce7050592b3d6267ae08ea2573908998c#patch4 Steve. > --- > fs/9p/vfs_dentry.c | 2 +- > fs/afs/dir.c | 2 +- > fs/coda/dir.c | 2 +- > fs/hfs/sysdep.c | 2 +- > fs/ncpfs/dir.c | 2 +- > fs/nfs/dir.c | 2 +- > fs/proc/proc_sysctl.c | 2 +- > fs/sysfs/dir.c | 2 +- > 8 files changed, 8 insertions(+), 8 deletions(-) > > diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c > index d529437..2785900 100644 > --- a/fs/9p/vfs_dentry.c > +++ b/fs/9p/vfs_dentry.c > @@ -106,7 +106,7 @@ static int v9fs_lookup_revalidate(struct dentry *dentry, struct nameidata *nd) > struct inode *inode; > struct v9fs_inode *v9inode; > > - if (nd->flags & LOOKUP_RCU) > + if (nd && nd->flags & LOOKUP_RCU) > return -ECHILD; > > inode = dentry->d_inode; > diff --git a/fs/afs/dir.c b/fs/afs/dir.c > index e22dc4b..93c1bbb 100644 > --- a/fs/afs/dir.c > +++ b/fs/afs/dir.c > @@ -607,7 +607,7 @@ static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd) > void *dir_version; > int ret; > > - if (nd->flags & LOOKUP_RCU) > + if (nd && nd->flags & LOOKUP_RCU) > return -ECHILD; > > vnode = AFS_FS_I(dentry->d_inode); > diff --git a/fs/coda/dir.c b/fs/coda/dir.c > index 1775158..804344d 100644 > --- a/fs/coda/dir.c > +++ b/fs/coda/dir.c > @@ -541,7 +541,7 @@ static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd) > struct inode *inode; > struct coda_inode_info *cii; > > - if (nd->flags & LOOKUP_RCU) > + if (nd && nd->flags & LOOKUP_RCU) > return -ECHILD; > > inode = de->d_inode; > diff --git a/fs/hfs/sysdep.c b/fs/hfs/sysdep.c > index 19cf291..1127ea3 100644 > --- a/fs/hfs/sysdep.c > +++ b/fs/hfs/sysdep.c > @@ -18,7 +18,7 @@ static int hfs_revalidate_dentry(struct dentry *dentry, struct nameidata *nd) > struct inode *inode; > int diff; > > - if (nd->flags & LOOKUP_RCU) > + if (nd && nd->flags & LOOKUP_RCU) > return -ECHILD; > > inode = dentry->d_inode; > diff --git a/fs/ncpfs/dir.c b/fs/ncpfs/dir.c > index aeed93a..69d6b55 100644 > --- a/fs/ncpfs/dir.c > +++ b/fs/ncpfs/dir.c > @@ -302,7 +302,7 @@ ncp_lookup_validate(struct dentry *dentry, struct nameidata *nd) > if (dentry == dentry->d_sb->s_root) > return 1; > > - if (nd->flags & LOOKUP_RCU) > + if (nd && nd->flags & LOOKUP_RCU) > return -ECHILD; > > parent = dget_parent(dentry); > diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c > index f430057..badda4e 100644 > --- a/fs/nfs/dir.c > +++ b/fs/nfs/dir.c > @@ -1123,7 +1123,7 @@ static int nfs_lookup_revalidate(struct dentry *dentry, struct nameidata *nd) > struct nfs_fattr *fattr = NULL; > int error; > > - if (nd->flags & LOOKUP_RCU) > + if (nd && nd->flags & LOOKUP_RCU) > return -ECHILD; > > parent = dget_parent(dentry); > diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c > index 3476bca..7df97f5 100644 > --- a/fs/proc/proc_sysctl.c > +++ b/fs/proc/proc_sysctl.c > @@ -796,7 +796,7 @@ static const struct inode_operations proc_sys_dir_operations = { > > static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd) > { > - if (nd->flags & LOOKUP_RCU) > + if (nd && nd->flags & LOOKUP_RCU) > return -ECHILD; > return !PROC_I(dentry->d_inode)->sysctl->unregistering; > } > diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c > index e6bb9b2..9f02776 100644 > --- a/fs/sysfs/dir.c > +++ b/fs/sysfs/dir.c > @@ -308,7 +308,7 @@ static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd) > struct sysfs_dirent *sd; > int is_dir; > > - if (nd->flags & LOOKUP_RCU) > + if (nd && nd->flags & LOOKUP_RCU) > return -ECHILD; > > sd = dentry->d_fsdata; > -- > 1.7.3.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
