Messages in this thread |  | | Date | Tue, 6 Aug 2024 09:42:23 -0700 | | Subject | Re: [tip: x86/urgent] x86/mm: Fix pti_clone_entry_text() for i386 | | From | Guenter Roeck <> |
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On 8/6/24 08:59, Peter Zijlstra wrote: > On Tue, Aug 06, 2024 at 05:46:53PM +0200, Peter Zijlstra wrote: >> On Tue, Aug 06, 2024 at 05:05:15PM +0200, Peter Zijlstra wrote: >>> On Tue, Aug 06, 2024 at 04:56:32PM +0200, Peter Zijlstra wrote: >>>> On Tue, Aug 06, 2024 at 07:25:42AM -0700, Guenter Roeck wrote: >>>> >>>>> I created http://server.roeck-us.net/qemu/x86-v6.11-rc2/ with all >>>>> the relevant information. Please let me know if you need anything else. >>>> >>>> So I grabbed that config, stuck it in the build dir I used last time and >>>> upgraded gcc-13 from 13.2 ro 13.3. But alas, my build runs successfully >>>> :/ >>>> >>>> Is there anything else special I missed? >>> >>> run.sh is not exacrlty the same this time, different CPU model, that >>> made it go. >>> >>> OK, lemme poke at this. >> >> Urgh, so crypto's late_initcall() does user-mode-helper based modprobe >> looking for algorithms before we kick off /bin/init :/ >> >> This makes things difficult. >> >> Urgh. > > So the problem is that mark_readonly() splits a code PMD due to NX. Then > the second pti_clone_entry_text() finds a kernel PTE but a user PMD > mapping for the same address (from the early clone) and gets upset. > > And we can't run mark_readonly() sooner, because initcall expect stuff > to be RW. But initcalls do modprobe, which runs user crap before we're > done initializing everything. > > This is a right mess, and I really don't know what to do.
And there was me thinking this one should be easy to solve. Oh well.
Maybe Linus has an idea ? I am getting a bit wary to reporting all those weird problems to him, though.
Guenter
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