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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Ralph Campbell <rcampbell@nvidia.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	nouveau@lists.freedesktop.org,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Christoph Hellwig" <hch@lst.de>
Subject: Re: [PATCH 2/2] mm/hmm: hmm_range_fault() infinite loop
Date: Tue, 27 Aug 2019 15:41:57 -0300	[thread overview]
Message-ID: <20190827184157.GA24929@ziepe.ca> (raw)
In-Reply-To: <20190823221753.2514-3-rcampbell@nvidia.com>

On Fri, Aug 23, 2019 at 03:17:53PM -0700, Ralph Campbell wrote:

> Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
>  mm/hmm.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/mm/hmm.c b/mm/hmm.c
> index 29371485fe94..4882b83aeccb 100644
> +++ b/mm/hmm.c
> @@ -292,6 +292,9 @@ static int hmm_vma_walk_hole_(unsigned long addr, unsigned long end,
>  	hmm_vma_walk->last = addr;
>  	i = (addr - range->start) >> PAGE_SHIFT;
>  
> +	if (write_fault && walk->vma && !(walk->vma->vm_flags & VM_WRITE))
> +		return -EPERM;

Can walk->vma be NULL here? hmm_vma_do_fault() touches it
unconditionally.

Jason


  parent reply	other threads:[~2019-08-27 18:42 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
2019-08-24 22:37   ` Christoph Hellwig
2019-08-26 18:02     ` Ralph Campbell
2019-08-26 18:09       ` Jason Gunthorpe
2019-08-26 18:21         ` Ralph Campbell
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 [this message]
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

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