Re: [PATCH] fs: System memory leak when running HTX with T10 DIF enabled

[Christoph Hellwig]

On Wed, Jun 28, 2017 at 12:44:00PM -0600, Jens Axboe wrote:
> On 06/28/2017 12:38 PM, Christoph Hellwig wrote:
> > On Wed, Jun 28, 2017 at 12:34:15PM -0600, Jens Axboe wrote:
> >> That's what I sent out.
> > 
> > Where?  Didn't see that anywhere..
> 
> Looks like you weren't CC'ed on the original thread. About an hour ago.
> 
> >> Here it is again. We should get this into 4.12,
> >> so would be great with a review or two.
> > 
> > Can we rename __bio_free to bio_uninit and add a comment to bio_init
> > that it must be paried with bio_uninit?
> 
> Let's keep it small for 4.12. We can do a cleanup on top of this for
> 4.13.

The rename is two additional lines for the patch, it's not going to
make a difference..

> > Except for that this looks fine, although there are a lot more callers
> > that should get this treatment..
> 
> Should only be an issue for on-stack bio's, since we don't go through
> the put/free path. Did a quick grep, looks like this is one of 3. One
> is floppy, which probably neither has DIF or uses blk-throttle. Then
> there's one in dm-bufio, didn't look too closely at that. Last one is
> this one.

Well, it's really all callers but bio_alloc_bioset itself that
will need this handling, as only bios that come from bio_alloc_bioset
will be freed through bio_free.  Most of them probably don't
support DIF, but they'll also miss the bio_disassociate_task call
this way, and will leak I/O context and css references if block
cgroup support is enabled.