Re: 2.5.1-pre5 not easy to boot with devfs

["Pierre ROUSSELET" <pierre.rousselet@wanadoo.fr>]

We have to be patient, my linux box is at home. I'll test your patch in a few hours.

Pierre

>Messsage du 03/12/2001 08:33
>De : Richard Gooch <rgooch@ras.ucalgary.ca>
>A : Pierre Rousselet <pierre.rousselet@wanadoo.fr>
>Copie à :  <linux-kernel@vger.kernel.org>,  <wli@holomorphy.com>
>Objet : Re: 2.5.1-pre5 not easy to boot with devfs  
>
> Pierre Rousselet writes:
> > As far as I can see,
> > 
> > when CONFIG_DEBUG_KERNEL is set
> >   and 
> > when devfsd is started at boot time
> > I get an Oops when remounting, rw the root fs :
> > 
> > Unable to handle kernel request at va 5a5a5a5e
> > ...
> > EIP: 0010:[<c01516f9>] Not tainted
> > ...
> > Process devfsd(pid:15,stackpage=cfd33000)
> 
> Ah, ha! I've found the problem. Perversely, I wasn't able to reproduce
> this bug until I booted a UP kernel. I've appended the fix. Please try
> this out. I have sufficient confidence in this fix that I'll make a
> proper release in a few minutes.
> 
> 				Regards,
> 
> 					Richard....
> Permanent: rgooch@atnf.csiro.au
> Current:   rgooch@ras.ucalgary.ca
> 
> diff -urN linux-2.4.17-pre2/Documentation/filesystems/devfs/ChangeLog linux/Documentation/filesystems/devfs/ChangeLog
> --- linux-2.4.17-pre2/Documentation/filesystems/devfs/ChangeLog	Sat Dec  1 10:48:46 2001
> +++ linux/Documentation/filesystems/devfs/ChangeLog	Sun Dec  2 23:23:12 2001
> @@ -1805,3 +1805,7 @@
>  
>  - Do not send CREATE, CHANGE, ASYNC_OPEN or DELETE events from devfsd
>    or children
> +===============================================================================
> +Changes for patch v199.1
> +
> +- Fixed bug in <devfsd_read>: was dereferencing freed pointer
> diff -urN linux-2.4.17-pre2/fs/devfs/base.c linux/fs/devfs/base.c
> --- linux-2.4.17-pre2/fs/devfs/base.c	Sat Dec  1 10:48:46 2001
> +++ linux/fs/devfs/base.c	Sun Dec  2 23:21:10 2001
> @@ -569,6 +569,9 @@
>  	       Do not send CREATE, CHANGE, ASYNC_OPEN or DELETE events from
>  	       devfsd or children.
>    v1.2
> +    20011202   Richard Gooch <rgooch@atnf.csiro.au>
> +	       Fixed bug in <devfsd_read>: was dereferencing freed pointer.
> +  v1.3
>  */
>  #include <linux/types.h>
>  #include <linux/errno.h>
> @@ -601,7 +604,7 @@
>  #include <asm/bitops.h>
>  #include <asm/atomic.h>
>  
> -#define DEVFS_VERSION            "1.2 (20011127)"
> +#define DEVFS_VERSION            "1.3 (20011202)"
>  
>  #define DEVFS_NAME "devfs"
>  
> @@ -3243,11 +3246,17 @@
>      tlen = rpos - *ppos;
>      if (done)
>      {
> +	devfs_handle_t parent;
> +
>  	spin_lock (&fs_info->devfsd_buffer_lock);
>  	fs_info->devfsd_first_event = entry->next;
>  	if (entry->next == NULL) fs_info->devfsd_last_event = NULL;
>  	spin_unlock (&fs_info->devfsd_buffer_lock);
> -	for (; de != NULL; de = de->parent) devfs_put (de);
> +	for (; de != NULL; de = parent)
> +	{
> +	    parent = de->parent;
> +	    devfs_put (de);
> +	}
>  	kmem_cache_free (devfsd_buf_cache, entry);
>  	if (ival > 0) atomic_sub (ival, &fs_info->devfsd_overrun_count);
>  	*ppos = 0;
>