Messages in this thread Patch in this message | | | Subject | Re: BUG at fs/namei.c:405 (nameidata_drop_rcu) | From | Herton Ronaldo Krzesinski <> | Date | Tue, 15 Feb 2011 18:17:08 -0200 |
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Em Sex, 2011-02-11 às 00:02 -0500, Chuck Ebbert escreveu: > Apparently hit this very early in nameidata_drop_rcu(): > > BUG_ON(!(nd->flags & LOOKUP_RCU)); > > The user reports he ran "fuser /var/cache/yum" while logged in to > an X session with his home directory mounted via NFS4. Home dirs > are normally automounted, but manually mounting the dir still > reproduces the problem.
I got a similar report too, and was able to reproduce here with nfs4 too.
We hit it at force_reval_path
From what I saw force_reval_path is never called with LOOKUP_RCU flag set. Who calls force_reval_path is __do_follow_link, and __do_follow_link is called from do_filp_open and do_follow_link. When do_filp_open calls it, it already dropped LOOKUP_RCU (if path rcu lookup didn't work). do_follow_link also calls it without LOOKUP_RCU set from what I'm seeing, as before each do_follow_link call nameidata_dentry_drop_rcu_maybe is called.
So simply removing again nameidata_drop_rcu from force_reval_path should do it. I'm running now on this change and didn't experience the same bug or other problems.
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
diff --git a/fs/namei.c b/fs/namei.c index ec4b2d0..7dcedbc 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -668,9 +668,7 @@ force_reval_path(struct path *path, struct nameidata *nd) return 0; if (!status) { - /* Don't d_invalidate in rcu-walk mode */ - if (nameidata_drop_rcu(nd)) - return -ECHILD; + BUG_ON(nd->flags & LOOKUP_RCU); d_invalidate(dentry); status = -ESTALE; }
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