Re: Oops in 2.6.13-rc5-git-current (0d317fb72fe3cf0f611608cf3a3015bbe6cd2a66)

[Ryan Anderson <ryan@michonline.com>]

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Alexander Nyberg wrote:
> (akpm: a fix for this needs to go into 2.6.13, inotify + nfs 
> trivially oopses otherwise, even if inotify isn't actively used)

This patch seems to have fixed it for me.

I upgraded to fdbd22dad31982b64a4e663fd056a8a7cfac9607 and applied this
patch on top of it, and I can't retrigger the oops.  (It seemed rather
easy to hit on the other kernel)

So, I guess:

Seems-to-fix-it: Ryan Anderson <ryan@michoneline.com>

> It looks like the following sequence is done in the wrong order.
> When vfs_unlink() is called from sys_unlink() it has taken a ref
> on the inode and sys_unlink() does the last iput() but when called
> from other callsites vfs_unlink() might do the last iput() and
> free inode, so inotify_inode_queue_event() will receive an already
> freed object and dereference an already freed object.
> 
> Signed-off-by: Alexander Nyberg <alexn@telia.com>
> 
> Index: mm/fs/namei.c
> ===================================================================
> --- mm.orig/fs/namei.c	2005-08-07 12:06:16.000000000 +0200
> +++ mm/fs/namei.c	2005-08-07 18:17:20.000000000 +0200
> @@ -1869,8 +1869,8 @@
>  	/* We don't d_delete() NFS sillyrenamed files--they still exist. */
>  	if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) {
>  		struct inode *inode = dentry->d_inode;
> -		d_delete(dentry);
>  		fsnotify_unlink(dentry, inode, dir);
> +		d_delete(dentry);
>  	}
>  
>  	return error;
> -
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