Messages in this thread | | | Subject | Re: [PATCH 1/2] mm/hmm: hmm_range_fault() NULL pointer bug | From | Ralph Campbell <> | Date | Mon, 26 Aug 2019 11:21:49 -0700 |
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On 8/26/19 11:09 AM, Jason Gunthorpe wrote: > On Mon, Aug 26, 2019 at 11:02:12AM -0700, Ralph Campbell wrote: >> >> 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. > > I'm really excited to see tests for hmm_range_fault()! > > Did you find this bug with the tests?? > > Jason >
Yes, I found both bugs with the tests. I started with Jerome's hmm_dummy driver and user level test code. Hopefully I can send it out this week.
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