Re: Potentially unbounded allocations in seq_read?

Al Viro
2013-12-12T14:22:07Z

On Thu, Dec 12, 2013 at 01:59:31PM +0000, Tvrtko Ursulin wrote:

> > a) *what* errors other than -ENAMETOOLONG?
>
> Is this your way of saying there can't be any other errors from d_path?

Check yourself... It is the only error that makes sense there and yes,
it is the only one being returned.

> > b) d_path() not fitting into 2Mb is definitely a bug. If you really have
> > managed to get a dentry tree 1 million levels deep, you have much worse
> > problems.
> > c) which kernel version it is?
>
> 3.10. I can't imagine this is an actual dentry tree somewhere, probably
> just a bug of some sort. I'll probably hunt it down completely some time
> next week, time permitting.

Sounds like missing backport of 118b23 ("cope with potentially long ->d_dname()
output for shmem/hugetlb"). It *is* in -stable (linux-3.10.y has it since
3.10.17 as commit ad4c3c), but if your tree doesn't have it, that's the one
to try first...