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authorAl Viro <viro@zeniv.linux.org.uk>2016-02-27 19:23:16 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2016-02-27 19:23:16 -0500
commitd4565649b6d6923369112758212b851adc407f0c (patch)
treefc877b8805e9393c4288bdf396cf223de2b144ad
parentc80567c82ae4814a41287618e315a60ecf513be6 (diff)
downloadlinux-stericsson-d4565649b6d6923369112758212b851adc407f0c.tar.gz
namei: ->d_inode of a pinned dentry is stable only for positives
both do_last() and walk_component() risk picking a NULL inode out of dentry about to become positive, *then* checking its flags and seeing that it's not negative anymore and using (already stale by then) value they'd fetched earlier. Usually ends up oopsing soon after that... Cc: stable@vger.kernel.org # v3.13+ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/namei.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/namei.c b/fs/namei.c
index e30deefad8f8..e0881c0bd228 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1743,11 +1743,11 @@ static int walk_component(struct nameidata *nd, int flags)
if (err < 0)
return err;
- inode = d_backing_inode(path.dentry);
seq = 0; /* we are already out of RCU mode */
err = -ENOENT;
if (d_is_negative(path.dentry))
goto out_path_put;
+ inode = d_backing_inode(path.dentry);
}
if (flags & WALK_PUT)
@@ -3192,12 +3192,12 @@ retry_lookup:
return error;
BUG_ON(nd->flags & LOOKUP_RCU);
- inode = d_backing_inode(path.dentry);
seq = 0; /* out of RCU mode, so the value doesn't matter */
if (unlikely(d_is_negative(path.dentry))) {
path_to_nameidata(&path, nd);
return -ENOENT;
}
+ inode = d_backing_inode(path.dentry);
finish_lookup:
if (nd->depth)
put_link(nd);