linux-kernel - Re: [PATCH v8 3/5] x86/pkeys: Update PKRU to enable all pkeys before XSAVE

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Message-ID: <1f3f60b3-1741-4ced-951c-8e103970170f@intel.com>
Date: Thu, 6 Feb 2025 10:21:36 -0800
From: Dave Hansen <dave.hansen@...el.com>
To: Dmitry Vyukov <dvyukov@...gle.com>, aruna.ramakrishna@...cle.com,
 mathieu.desnoyers@...icios.com, peterz@...radead.org, paulmck@...nel.org,
 boqun.feng@...il.com
Cc: dave.hansen@...ux.intel.com, jannh@...gle.com, jeffxu@...omium.org,
 jorgelo@...omium.org, keescook@...omium.org, keith.lucas@...cle.com,
 linux-kernel@...r.kernel.org, linux-mm@...ck.org, mingo@...nel.org,
 rick.p.edgecombe@...el.com, sroettger@...gle.com, tglx@...utronix.de,
 x86@...nel.org
Subject: Re: [PATCH v8 3/5] x86/pkeys: Update PKRU to enable all pkeys before
 XSAVE

On 2/4/25 02:01, Dmitry Vyukov wrote:
>> But this updated PKRU value is also pushed onto the sigframe, which
>> means the register value restored from sigcontext will be different from
>> the user-defined one, which is unexpected. Fix that by overwriting the
>> PKRU value on the sigframe with the original, user-defined PKRU.
> 
> This unfortunatly seems to be broken for rseq user-space writes.

Hi Dmitry,

Are you saying that Aruna's patch caused a regression in the rseq code?
Or that the rseq code has a separate but similar issue to the one that
Aruna's patch fixed?