On Thu, May 07, 2015 at 03:33:21PM -0400, Steven Rostedt wrote:
> On Thu, 7 May 2015 19:43:43 +0100
> Al Viro <v...@zeniv.linux.org.uk> wrote:
> 
> 
> > Actually, could you try the following on top of -rc2?
> 
> Gives me the following on boot up:

Gah...  Sorry, I'm an idiot - *path is left uninitialized in that
case.  Fixed.  Could you see if that works?

diff --git a/fs/namei.c b/fs/namei.c
index 4a8d998b..2c8b94e 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1415,6 +1415,7 @@ static int lookup_fast(struct nameidata *nd,
         */
        if (nd->flags & LOOKUP_RCU) {
                unsigned seq;
+               bool negative;
                dentry = __d_lookup_rcu(parent, &nd->last, &seq);
                if (!dentry)
                        goto unlazy;
@@ -1424,8 +1425,11 @@ static int lookup_fast(struct nameidata *nd,
                 * the dentry name information from lookup.
                 */
                *inode = dentry->d_inode;
+               negative = d_is_negative(dentry);
                if (read_seqcount_retry(&dentry->d_seq, seq))
                        return -ECHILD;
+               if (negative)
+                       return -ENOENT;
 
                /*
                 * This sequence count validates that the parent had no
@@ -1472,6 +1476,10 @@ unlazy:
                goto need_lookup;
        }
 
+       if (unlikely(d_is_negative(dentry))) {
+               dput(dentry);
+               return -ENOENT;
+       } 
        path->mnt = mnt;
        path->dentry = dentry;
        err = follow_managed(path, nd->flags);
@@ -1583,10 +1591,10 @@ static inline int walk_component(struct nameidata *nd, 
struct path *path,
                        goto out_err;
 
                inode = path->dentry->d_inode;
+               err = -ENOENT;
+               if (d_is_negative(path->dentry))
+                       goto out_path_put;
        }
-       err = -ENOENT;
-       if (d_is_negative(path->dentry))
-               goto out_path_put;
 
        if (should_follow_link(path->dentry, follow)) {
                if (nd->flags & LOOKUP_RCU) {
@@ -3036,14 +3044,13 @@ retry_lookup:
 
        BUG_ON(nd->flags & LOOKUP_RCU);
        inode = path->dentry->d_inode;
-finish_lookup:
-       /* we _can_ be in RCU mode here */
        error = -ENOENT;
        if (d_is_negative(path->dentry)) {
                path_to_nameidata(path, nd);
                goto out;
        }
-
+finish_lookup:
+       /* we _can_ be in RCU mode here */
        if (should_follow_link(path->dentry, !symlink_ok)) {
                if (nd->flags & LOOKUP_RCU) {
                        if (unlikely(nd->path.mnt != path->mnt ||
--
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