Displaying 4 results from an estimated 4 matches for "vm_fault_write".
2019 Aug 23
6
[PATCH 0/2] mm/hmm: two bug fixes for hmm_range_fault()
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
2016 Oct 26
2
CVE-2016-5195 DirtyCOW : Critical Linux Kernel Flaw
...y(!page)) {
if ((flags & FOLL_DUMP) ||
!is_zero_pfn(pte_pfn(pte)))
@@ -1290,7 +1309,6 @@ split_fallthrough:
*/
mark_page_accessed(page);
}
-unlock:
pte_unmap_unlock(ptep, ptl);
out:
return page;
@@ -1489,17 +1507,13 @@ int __get_user_pages(struct task_struct
* The VM_FAULT_WRITE bit tells us that
* do_wp_page has broken COW when necessary,
* even if maybe_mkwrite decided not to set
- * pte_write. We can thus safely do subsequent
- * page lookups as if they were reads. But only
- * do so when looping for pte_write is futile:
- * in some cases use...
2016 Oct 25
5
CVE-2016-5195 DirtyCOW : Critical Linux Kernel Flaw
On Tue, 25 Oct 2016 10:06:12 +0200
Christian Anthon <anthon at rth.dk> wrote:
> What is the best approach on centos 6 to mitigate the problem is
> officially patched? As far as I can tell Centos 6 is vulnerable to
> attacks using ptrace.
I can confirm that c6 is vulnerable, we're running a patched kernel
(local build) using a rhel6 adaptation of the upstream fix.
Ask
2019 Aug 23
0
[PATCH 2/2] mm/hmm: hmm_range_fault() infinite loop
...e 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
handle_mm_fault().
Signed-off-by: Ralph Campbell <rcampbell at nvidia.com>
---...