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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Jun 24, 2020 at 12:43:20PM +0530, Amit Daniel Kachhap wrote: > On 6/23/20 8:17 PM, Dave Martin wrote: > > On Tue, Jun 23, 2020 at 06:47:02PM +0530, Amit Daniel Kachhap wrote: > > > On 6/22/20 8:05 PM, Dave Martin wrote: > > > > On Thu, Jun 18, 2020 at 10:40:28AM +0530, Amit Daniel Kachhap wrote: > > > > > This patch modifies the address authentication cpufeature type to EXACT > > > > >from earlier LOWER_SAFE as the different configurations added for Armv8.6 > > > > > enhanced PAC have different behaviour and there is no tunable to enable the > > > > > lower safe versions. $ git grep 'This patch' Documentation/process/submitting-patches.rst > > > > Does a corresponding patch need to go to stable? As things stand, I > > > > think older kernels that support pointer auth will go wrong on v8.7+ > > > > hardware that has these features. > > Yes It makes to add this patch to the stable version. > > @Catalin, @Will - Shall I send this one with a fix subject line? Please let > me know your suggestion. What exactly goes wrong? As far as I can tell, we will taint and probably (?) crash shortly afterwards if you run an old kernel on hardware with mismatched pointer auth. If that's the case, I don't think this warrants stable (especially since this file has seen enough churn that the backports are likely risky). Can you confirm that things only go wrong if we have a mismatched system, and ideally provide an example of what the crash looks like (you should be able to get a fast model to emulate this setup)? Cheers, Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel