On 02/22/2011 10:14 AM, Joel Becker wrote: > On Mon, Feb 21, 2011 at 11:47:09AM +0100, Jiri Slaby wrote: >>> I think you're right about the superfluous test, but I need more >>> investigation to see what's going on. Thanks for the report. >>> What was causing attach_group() to fail? Do you know? >> >> Dunno, I just modprobe'd the configfs example from Doc dir >> (configfs_example_macros). > > I'm going to revisit the failed example (which shouldn't fail, I > would think). Got it. One needs to load both of the examples. The second loaded kills the box. > Can you try the following patch to safely handle the > failure rather than crashing the kernel? Yes, it helps. But I need also (cut & paste): --- a/Documentation/filesystems/configfs/configfs_example_explicit.c +++ b/Documentation/filesystems/configfs/configfs_example_explicit.c @@ -464,7 +464,7 @@ static int __init configfs_example_init(void) return 0; out_unregister: - for (; i >= 0; i--) { + for (i--; i >= 0; i--) { configfs_unregister_subsystem(example_subsys[i]); } --- a/Documentation/filesystems/configfs/configfs_example_macros.c +++ b/Documentation/filesystems/configfs/configfs_example_macros.c @@ -427,7 +427,7 @@ static int __init configfs_example_init(void) return 0; out_unregister: - for (; i >= 0; i--) { + for (i--; i >= 0; i--) { configfs_unregister_subsystem(example_subsys[i]); } > From 68bbb327c48fdcdc48b71435d19b9e899745adf0 Mon Sep 17 00:00:00 2001 > From: Joel Becker <jlbec@xxxxxxxxxxxx> > Date: Tue, 22 Feb 2011 01:09:49 -0800 > Subject: [PATCH] configfs: Don't try to d_delete() negative dentries. > > When configfs is faking mkdir() on its subsystem or default group > objects, it starts by adding a negative dentry. It then tries to > instantiate the group. If that should fail, it must clean up after > itself. > > I was using d_delete() here, but configfs_attach_group() promises to > return an empty dentry on error. d_delete() explodes with the entry > dentry. Let's try d_drop() instead. The unhashing is what we want for > our dentry. > > Signed-off-by: Joel Becker <jlbec@xxxxxxxxxxxx> > --- > fs/configfs/dir.c | 6 ++++-- > 1 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c > index 90ff3cb..2af26b8 100644 > --- a/fs/configfs/dir.c > +++ b/fs/configfs/dir.c > @@ -689,7 +689,8 @@ static int create_default_group(struct config_group *parent_group, > sd = child->d_fsdata; > sd->s_type |= CONFIGFS_USET_DEFAULT; > } else { > - d_delete(child); > + BUG_ON(child->d_inode); > + d_drop(child); > dput(child); > } > } > @@ -1683,7 +1684,8 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys) > err = configfs_attach_group(sd->s_element, &group->cg_item, > dentry); > if (err) { > - d_delete(dentry); > + BUG_ON(dentry->d_inode); > + d_drop(dentry); > dput(dentry); > } else { > spin_lock(&configfs_dirent_lock); thanks, -- js -- 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