> On Nov 26, 2021, at 2:21 AM, Anton Ivanov <anton.ivanov@xxxxxxxxxxxxxxxxxx> wrote: > > > > On 26/11/2021 06:08, Nadav Amit wrote: >> Below is a patch to address CVE-2021-4002 [1] that I created to backport >> to 4.9. The stable kernels of 4.14 and prior ones do not have unified >> TLB flushing code, and I managed to mess up the arch code a couple of >> times. >> Now that the CVE is public, I would appreciate your review of this >> patch. I send 4.9 for review - the other ones (4.14 and prior) are >> pretty similar. >> [1] https://www.openwall.com/lists/oss-security/2021/11/25/1 >> Thanks, >> Nadav > > I do not quite see the rationale for patching um > > It supports only standard size pages. You should not be able to map a huge page there (and hugetlbfs). > > I have "non-standard page size" somewhere towards the end of my queue, but it keeps falling through - not enough spare time to work on it. Thanks for your review. I did not look at the dependencies, so I did not even look if hugetlbfs depends on !um. Do you prefer that for um, I will just do a BUG()? I prefer to have a stub just to avoid potential build issues.
