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charset="UTF-8" X-Stat-Signature: 7jetkjxk6f9xg4pt4bjoeiq3r61otkin X-Rspam-User: X-Rspamd-Queue-Id: A049280006 X-Rspamd-Server: rspam06 X-HE-Tag: 1674798923-284007 X-HE-Meta: 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 zKKWuLPZ 5LUGSvgoRzwwqJKj7TRVrkK+/qFr1mQqC44b4mSv+QGbCgTjIs7l+PfW8lcwon80scrg+9mR6f0ECRCtosJ6guaAhtpM9Fjo0MR/7uNZHXDv6r0uvLnTR94zMVOtDnJ8KzrWncviixK7LlrVRTgWcDWIsonf7fhodOL6hiU20B8Mi6yaMmO+a4rE2JMZfWUfEcw8jqaYaJ9lEG7ZJ6h0n6SFgZ/lTtPNX/5JBKEI2waimSfxANt8jvuKJRItEnYweF815OUKECVeiySIalkKyHIPZBjI/FkkYBeBE+11HALBPO95TtqIwggNawDVplyn6vFT/NcdgaAzOGX5bjRQJhoyskTSpbr0KlwUO1PFanf4FGGSGB+jILslDSxV5E4WAYpX6bp938CCQmSWtTcj2/8K30g== 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: On Thu, Jan 26, 2023 at 9:36 PM Jeff Xu wrote: > > On Wed, Jan 25, 2023 at 5:43 PM Jeff Xu wrote: > > > > On Wed, Jan 25, 2023 at 11:13 AM Dave Hansen wrote: > > > > > > On 1/25/23 11:02, Jeff Xu wrote: > > > > I'm investigating if there is a need to backport x86/pkeys > > > > fix/feature into earlier kernel versions, Chrome is starting to use > > > > PKEY in x86, and I hope experts here can give advice on this. > > > > > > > > For background, ChromeOS regularly syncs with upstream kernel > > > > versions, and has production that uses 4.4/4.14/4.19/5.4/5.10/5.15. > > > To be honest, I haven't got the foggiest idea what you need to backport. > > > I can barely keep track of mainline. > > > > > > Are there really production 4.4 kernels that you need to run on > > > pkey-capable hardware? That would mean running a 2015-era kernel on a > > > CPU released in late 2020. I think Q3'2020 is when the 11th gen CPUs > > > came out which were the first non-server CPUs that had pkeys. > > > > > Thanks! > > For 11th gen CPUs, chromebook uses 5.4 and above, so that eliminate > > half of the versions. > > > > > On a positive note, the pkeys selftest has been pretty consistently > > > updated as we find bugs. I'd be curious how well a mainline version of > > > that selftests runs on old kernels. But, I'm too scared to find out > > > what's down that particular rabbit hole myself. > > > I took the latest selftest from main and run on 5.15 kernel, > all passed except test_ptrace_modifies_pkru > assert() at protection_keys.c::1623 test_nr: 20 iteration: 1 > > Is there a bugfix for the ptrace area ? > Thanks What 5.15 series kernel did you run it on? The patches for that didn't get backported until 5.15.88 - Kyle > > > > I can start with 5.10 or 5.15, it seems there are quite some changes though, > > for example, this one by Thomas > > https://lore.kernel.org/lkml/20210623120127.327154589@linutronix.de/ > > > > My question is, if I have to pick a version that doesn't require a lot > > of backporting, > > and functionality is stable enough, what version would this be ? 5.4/5.10/5.15 ? > > > > -Jeff