search for: hmm_vma_do_fault

..._(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

I have been working on converting Jerome's hmm_dummy driver and self tests into a stand-alone set of tests to be included in tools/testing/selftests/vm and came across these two bug fixes in the process. The tests aren't quite ready to be posted as a patch. I'm posting the fixes now since I thought they shouldn't wait. They should probably have a fixes line but with all the HMM

...the vma range. hmm_range_fault() /* calls find_vma() but no range check */ walk_page_range() /* calls find_vma(), sets walk->vma = NULL */ __walk_page_range() walk_pgd_range() walk_p4d_range() walk_pud_range() hmm_vma_walk_hole() hmm_vma_walk_hole_() hmm_vma_do_fault() handle_mm_fault(vma=0) Signed-off-by: Ralph Campbell <rcampbell at nvidia.com> --- mm/hmm.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/mm/hmm.c b/mm/hmm.c index fc05c8fe78b4..29371485fe94 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -229,6 +229,...

...ng 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 > walk->vma can be NULL. hmm_vma_do_fault() no longer touches it unconditionally, that is what the preceding patch fixes. I suppose I could change hmm_vma_walk_hole_() to check for NULL and fill in the pfns[] array, I just chose to handle i...

...or VM_WRITE if the caller requests a page to be faulted in with write permission (via the hmm_range.pfns[] value). If the vma is write protected, this can result in an infinite loop: hmm_range_fault() walk_page_range() ... hmm_vma_walk_hole() hmm_vma_walk_hole_() hmm_vma_do_fault() handle_mm_fault(FAULT_FLAG_WRITE) /* returns VM_FAULT_WRITE */ /* returns -EBUSY */ /* returns -EBUSY */ /* returns -EBUSY */ /* loops on -EBUSY and range->valid */ Prevent this by checking for vma->vm_flags & VM_WRITE before calling h...

...ow please? Otherwise Reviewed-by: Jason Gunthorpe <jgg at mellanox.com> Frankly, I find the 'int *locked' scheme of GUP easier to understand.. diff --git a/mm/hmm.c b/mm/hmm.c index 16b6731a34db79..54b3a4162ae949 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -301,8 +301,10 @@ static int hmm_vma_do_fault(struct mm_walk *walk, unsigned long addr, flags |= hmm_vma_walk->block ? 0 : FAULT_FLAG_ALLOW_RETRY; flags |= write_fault ? FAULT_FLAG_WRITE : 0; ret = handle_mm_fault(vma, addr, flags); - if (ret & VM_FAULT_RETRY) + if (ret & VM_FAULT_RETRY) { + /* Note, handle_mm_fault did up_re...

...stoph Hellwig <hch at lst.de> --- mm/hmm.c | 113 ++++++++++++++++++++++++------------------------------- 1 file changed, 50 insertions(+), 63 deletions(-) diff --git a/mm/hmm.c b/mm/hmm.c index 902f5fa6bf93..06041d4399ff 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -252,18 +252,17 @@ static int hmm_vma_do_fault(struct mm_walk *walk, unsigned long addr, return -EFAULT; } -static int hmm_pfns_bad(unsigned long addr, - unsigned long end, - struct mm_walk *walk) +static int hmm_pfns_fill(unsigned long addr, + unsigned long end, + struct hmm_range *range, + enum hmm_pfn_value_e value) { - st...

On Mon, Jul 22, 2019 at 3:14 PM Christoph Hellwig <hch at lst.de> wrote: > > We should not have two different error codes for the same condition. In > addition this really complicates the code due to the special handling of > EAGAIN that drops the mmap_sem due to the FAULT_FLAG_ALLOW_RETRY logic > in the core vm. > > Signed-off-by: Christoph Hellwig <hch at

Here are seven more patches for things I found to clean up. This was based on top of Christoph's seven patches: "hmm_range_fault related fixes and legacy API removal v3". I assume this will go into Jason's tree since there will likely be more HMM changes in this cycle. Changes from v1 to v2: Added AMD GPU to hmm_update removal. Added 2 patches from Christoph. Added 2 patches as

Hi Jérôme, Ben and Jason, below is a series against the hmm tree which fixes up the mmap_sem locking in nouveau and while at it also removes leftover legacy HMM APIs only used by nouveau. The first 4 patches are a bug fix for nouveau, which I suspect should go into this merge window even if the code is marked as staging, just to avoid people copying the breakage. Changes since v2: - new patch

Hi Dan, Jérôme and Jason, below is a series that cleans up the dev_pagemap interface so that it is more easily usable, which removes the need to wrap it in hmm and thus allowing to kill a lot of code Note: this series is on top of Linux 5.2-rc6 and has some minor conflicts with the hmm tree that are easy to resolve. Diffstat summary: 34 files changed, 379 insertions(+), 1016 deletions(-) Git

These changes are based on Jason's latest hmm branch. Patch 1 was previously posted here [1] but was dropped from the orginal series. Hopefully, the tests will reduce concerns about edge conditions. I'm sure more tests could be usefully added but I thought this was a good starting point. [1] https://lore.kernel.org/linux-mm/20190726005650.2566-6-rcampbell at nvidia.com/ Ralph Campbell