AMD-GFX Archive on lore.kernel.org
 help / color / mirror / Atom feed
From: Ralph Campbell <rcampbell-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
To: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
Cc: nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org,
	linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
	"Jérôme Glisse" <jglisse-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	"Jason Gunthorpe" <jgg-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>,
	amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org,
	"Andrew Morton"
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Subject: Re: [PATCH 1/2] mm/hmm: hmm_range_fault() NULL pointer bug
Date: Mon, 26 Aug 2019 11:02:12 -0700	[thread overview]
Message-ID: <e2ecc1a7-0d2f-5957-e6cb-b3c86c085d80@nvidia.com> (raw)
In-Reply-To: <20190824223754.GA21891-jcswGhMUV9g@public.gmane.org>


On 8/24/19 3:37 PM, Christoph Hellwig wrote:
> On Fri, Aug 23, 2019 at 03:17:52PM -0700, Ralph Campbell wrote:
>> Although hmm_range_fault() calls find_vma() to make sure that a vma exists
>> before calling walk_page_range(), hmm_vma_walk_hole() can still be called
>> with walk->vma == NULL if the start and end address are not contained
>> within the vma range.
> 
> Should we convert to walk_vma_range instead?  Or keep walk_page_range
> but drop searching the vma ourselves?
> 
> Except for that the patch looks good to me:
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> 

I think keeping the call to walk_page_range() makes sense.
Jason is hoping to be able to snapshot a range with & without vmas
and have the pfns[] filled with empty/valid entries as appropriate.

I plan to repost my patch changing hmm_range_fault() to use
walk.test_walk which will remove the call to find_vma().
Jason had some concerns about testing it so that's why I have
been working on some HMM self tests before resending it.
_______________________________________________
amd-gfx mailing list
amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx

  parent reply	other threads:[~2019-08-26 18:02 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-23 22:17 [PATCH 0/2] mm/hmm: two bug fixes for hmm_range_fault() Ralph Campbell
2019-08-23 22:17 ` [PATCH 1/2] mm/hmm: hmm_range_fault() NULL pointer bug Ralph Campbell
     [not found]   ` <20190823221753.2514-2-rcampbell-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2019-08-24 22:37     ` Christoph Hellwig
     [not found]       ` <20190824223754.GA21891-jcswGhMUV9g@public.gmane.org>
2019-08-26 18:02         ` Ralph Campbell [this message]
2019-08-26 18:09           ` Jason Gunthorpe
2019-08-26 18:21             ` Ralph Campbell
     [not found] ` <20190823221753.2514-1-rcampbell-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2019-08-23 22:17   ` [PATCH 2/2] mm/hmm: hmm_range_fault() infinite loop Ralph Campbell
2019-08-24 22:39     ` Christoph Hellwig
2019-08-27 18:41     ` Jason Gunthorpe
     [not found]       ` <20190827184157.GA24929-uk2M96/98Pc@public.gmane.org>
2019-08-27 20:16         ` Ralph Campbell
2019-08-27 22:22           ` Jason Gunthorpe
2019-08-27 22:48 ` [PATCH 0/2] mm/hmm: two bug fixes for hmm_range_fault() Jason Gunthorpe

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=e2ecc1a7-0d2f-5957-e6cb-b3c86c085d80@nvidia.com \
    --to=rcampbell-ddmlm1+adcrqt0dzr+alfa@public.gmane.org \
    --cc=akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org \
    --cc=amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org \
    --cc=dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org \
    --cc=hch-jcswGhMUV9g@public.gmane.org \
    --cc=jgg-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org \
    --cc=jglisse-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org \
    --cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
    --cc=linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org \
    --cc=nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox