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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 0CED0C0004 X-Stat-Signature: pz5p9e3ct6wmae5suxx5hs7eipz4c76o X-Rspam-User: X-HE-Tag: 1727792870-676470 X-HE-Meta: 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 9jJXqznX gr6Ij3MalN58O77h9LNrQ4SfrecxJbB5u8ZDC9XR+vKyEvh8RTx8yFYTSRLF7DncBtcN87R0bLZzfv8fi+1ZNrNyFfko1GqSIGdAGf9jMaawsC9ZauNqufWEW+N8E3vEN0gjRYeJfWgZe/EU= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Peter, On 08/08/2024 12:25, Ryan Roberts wrote: > On 07/08/2024 19:59, Peter Xu wrote: >> On Wed, Aug 07, 2024 at 12:18:18PM +0200, David Hildenbrand wrote: >>> On 07.08.24 10:58, David Hildenbrand wrote: >>>> On 06.08.24 22:29, Peter Xu wrote: >>>>> On Tue, Aug 06, 2024 at 06:37:55PM +0200, David Hildenbrand wrote: >>>>>> On 06.08.24 17:15, Ryan Roberts wrote: >>>>>>> Hi Peter, David, >>>>> >>>>> Hi, Ryan, >>>>> >>>>>>> >>>>>>> syzkaller has found an issue (at least on arm64, but I suspect it will be >>>>>>> visible on x86_64 too) that triggers the following warning: >>>>> >>>>> This is true. I can easily reproduce.. >>>>> [...] >> When I'm looking at this specific issue again, it's more than ptes that >> should need to remove the uffd-wp bit. We have: >> >> - pmd/pud/hugetlb in other paths that will need similar care.. >> >> - move_page_tables() smartness on HAVE_MOVE_PUD.. where we may need to >> walk the pmd page removing the bits when necessary.. >> >> - more importantly, mremap_userfaultfd_prep() might be too late if it's >> after moving pgtables.. >> >> - [not yet started looking] the mlock issue Ryan mentioned.. >> >> Looks like we'll need more things to fix and test.. >> >> I wished if I can simply disable UFFD_WP + EVENT_REMAP, but I think even >> with that, by default when mremap() we should still logically tear down all >> those uffd-wp bits which is the same as !EVENT_REMAP now.. >> >> Let me know if anyone would like to beat me to it on fixing the whole >> thing, I'd be more than happy.. > > Afraid I won't be able to sign up to doing that work. > > Otherwise, I'll probably need to postpone >> the fix of this issue for 1-2 weeks but finish some other things first.. I'm not sure if there was any progress on this? We are still seeing the problem on v6.12-rc1. Thanks, Ryan