Re: [PATCH] fix oops in namespace.c

[viro@parcelfarce.linux.theplanet.co.uk]

On Mon, May 19, 2003 at 12:57:37AM +0200, Andries.Brouwer@cwi.nl wrote:
> Number four in the series of namespace.c fixes:
> 
> A familar type of Oops: d_path() can return an error ENAMETOOLONG,
> and if we fail to test a segfault occurs.
> 
> So we must test. What we do is a different matter.
> Rather arbitrarily I return the string " (too long)"
> for use in /proc/mounts.

There's a better fix.  Since we are going to use seq_...() anyway,
we both have a buffer and length.  Moreover, if there's not enough
space to store the result, generic seq_file code will take care
about expanding buffer and calling us again.

IOW, we need to add seq_path(seq_file *, vfsmount *, dentry *) that would
DTRT.  That would have a benefit of avoiding extra allocation/freeing.

I'll send such patch in ~20 minutes.  BTW, it's also needed for /proc/swaps
and can be used for /proc/<pid>/maps if we switch it to seq_file (worth
doing anyway).

PS: math.psu.edu account is alive, but I'm not checking it often these
days, so Cc there is not too useful.