Re: [BUG] 2.6.19-rc3 autofs crash on my IA64 box

[Ian Kent <raven@themaw.net>]

On Fri, 3 Nov 2006, Ian Kent wrote:

> On Thu, 2 Nov 2006, Yasunori Goto wrote:
> 
> > Hello.
> > 
> > > hi,
> > >   2.6.19-rc3 kernel crashes on my IA64 box, it seems the problem
> > > of autofs fs. I debug this problem, if autofs kernel does not
> > > match daemon version, it will call autofs_catatonic_mode.
> > > But at that time sbi->pipe is NULL.
> > > 
> > > void autofs_catatonic_mode(struct autofs_sb_info *sbi)
> > > {
> > >    .........
> > >    fput(sbi->pipe);        /* Close the pipe */
> > > 	^^^^^^^^^^^^
> > >  	sbi->pipe seems NULL;
> > >    autofs_hash_dputall(&sbi->dirhash); /* Remove all dentry pointers */
> > > }
> > > 
> > 
> > My box crashed too.
> > 
> > Following fix does not seem enough.
> > http://marc.theaimsgroup.com/?l=linux-kernel&m=116110204104327&w=2
> > If version does not match at autofs_fill_super(), then sbi->pipe
> > is not set yet.
> > I suppose something like following patch is necessary.
> > 
> > Thanks.
> > 
> > -------------
> > Index: stocktest/fs/autofs/waitq.c
> > ===================================================================
> > --- stocktest.orig/fs/autofs/waitq.c	2006-03-10 11:36:40.000000000 +0900
> > +++ stocktest/fs/autofs/waitq.c	2006-11-02 18:44:58.000000000 +0900
> > @@ -40,7 +40,8 @@ void autofs_catatonic_mode(struct autofs
> >  		wake_up(&wq->queue);
> >  		wq = nwq;
> >  	}
> > -	fput(sbi->pipe);	/* Close the pipe */
> > +	if (sbi->pipe)
> > +		fput(sbi->pipe);	/* Close the pipe */
> >  	autofs_hash_dputall(&sbi->dirhash); /* Remove all dentry pointers */
> >  }
> 
> I've checked this and this is not the only problem.
> Also autofs4_ is called with s->s_root NULL in this case.

Oops, that autofs4_ should be autofs4_force_release

> 
> The attached patch ensures that the autofs filesystem is initialized to be 
> catatonic until super block setup is complete which avoids the problem 
> above. It also checks s->s_root before use.
> 
> Could someone seeing this problem try this patch out please.
> 
> Ian
> 
> ---
> --- linux-2.6.19-rc4-mm2/fs/autofs4/waitq.c.mount-fail-panic	2006-11-03 15:35:01.000000000 +0800
> +++ linux-2.6.19-rc4-mm2/fs/autofs4/waitq.c	2006-11-03 15:35:22.000000000 +0800
> @@ -41,10 +41,8 @@ void autofs4_catatonic_mode(struct autof
>  		wake_up_interruptible(&wq->queue);
>  		wq = nwq;
>  	}
> -	if (sbi->pipe) {
> -		fput(sbi->pipe);	/* Close the pipe */
> -		sbi->pipe = NULL;
> -	}
> +	fput(sbi->pipe);	/* Close the pipe */
> +	sbi->pipe = NULL;
>  }
>  
>  static int autofs4_write(struct file *file, const void *addr, int bytes)
> --- linux-2.6.19-rc4-mm2/fs/autofs4/inode.c.mount-fail-panic	2006-11-03 14:42:46.000000000 +0800
> +++ linux-2.6.19-rc4-mm2/fs/autofs4/inode.c	2006-11-03 15:20:55.000000000 +0800
> @@ -99,6 +99,9 @@ static void autofs4_force_release(struct
>  	struct dentry *this_parent = sbi->sb->s_root;
>  	struct list_head *next;
>  
> +	if (!sbi->sb->s_root)
> +		return;
> +
>  	spin_lock(&dcache_lock);
>  repeat:
>  	next = this_parent->d_subdirs.next;
> @@ -310,7 +313,8 @@ int autofs4_fill_super(struct super_bloc
>  	s->s_fs_info = sbi;
>  	sbi->magic = AUTOFS_SBI_MAGIC;
>  	sbi->pipefd = -1;
> -	sbi->catatonic = 0;
> +	sbi->pipe = NULL;
> +	sbi->catatonic = 1;
>  	sbi->exp_timeout = 0;
>  	sbi->oz_pgrp = process_group(current);
>  	sbi->sb = s;
> @@ -388,6 +392,7 @@ int autofs4_fill_super(struct super_bloc
>  		goto fail_fput;
>  	sbi->pipe = pipe;
>  	sbi->pipefd = pipefd;
> +	sbi->catatonic = 0;
>  
>  	/*
>  	 * Success! Install the root dentry now to indicate completion.
> --- linux-2.6.19-rc4-mm2/fs/autofs/waitq.c.mount-fail-panic	2006-11-03 15:36:11.000000000 +0800
> +++ linux-2.6.19-rc4-mm2/fs/autofs/waitq.c	2006-11-03 15:37:04.000000000 +0800
> @@ -41,6 +41,7 @@ void autofs_catatonic_mode(struct autofs
>  		wq = nwq;
>  	}
>  	fput(sbi->pipe);	/* Close the pipe */
> +	sbi->pipe = NULL;
>  	autofs_hash_dputall(&sbi->dirhash); /* Remove all dentry pointers */
>  }
>  
> --- linux-2.6.19-rc4-mm2/fs/autofs/inode.c.mount-fail-panic	2006-11-03 14:40:56.000000000 +0800
> +++ linux-2.6.19-rc4-mm2/fs/autofs/inode.c	2006-11-03 15:24:01.000000000 +0800
> @@ -136,7 +136,8 @@ int autofs_fill_super(struct super_block
>  
>  	s->s_fs_info = sbi;
>  	sbi->magic = AUTOFS_SBI_MAGIC;
> -	sbi->catatonic = 0;
> +	sbi->pipe = NULL;
> +	sbi->catatonic = 1;
>  	sbi->exp_timeout = 0;
>  	sbi->oz_pgrp = process_group(current);
>  	autofs_initialize_hash(&sbi->dirhash);
> @@ -180,6 +181,7 @@ int autofs_fill_super(struct super_block
>  	if ( !pipe->f_op || !pipe->f_op->write )
>  		goto fail_fput;
>  	sbi->pipe = pipe;
> +	sbi->catatonic = 0;
>  
>  	/*
>  	 * Success! Install the root dentry now to indicate completion.
> -
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