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From: Daniel Micay <danielmicay@gmail.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
	Dave Hansen <dave.hansen@intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	kernel list <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H . Peter Anvin" <hpa@zytor.com>, X86 ML <x86@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Will Deacon <will.deacon@arm.com>,
	Andy Lutomirski <luto@kernel.org>,
	jroedel@suse.de
Subject: Re: [PATCH 1/2] x86/pkeys: copy pkey state at fork()
Date: Mon, 29 Oct 2018 04:55:07 -0400	[thread overview]
Message-ID: <CA+DvKQKUCVN5OUxShwxhXUnx5Qx0EUZSCeKOAUYR2CWW+NkO_g@mail.gmail.com> (raw)
In-Reply-To: <20181029063626.GD128403@gmail.com>

Yeah, a no-op pkey_alloc flag tied to this patch to provide a way to
detect if pkey state is preserved on fork, since kernels without the
patch would report EINVAL. Something like
PKEY_ASSERT_FORK_INHERIT_STATE would make sense. Otherwise, it's
going to be quite painful to adopt this in userspace software without kernel
version checks. Most software can't accept causing a crash / abort
after forking in environments not applying all the stable kernel
patches, or in fresh OS installs that aren't fully updated + rebooted yet.

  reply	other threads:[~2018-10-29  8:55 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-26 19:51 Dave Hansen
2018-10-26 19:51 ` [PATCH 2/2] x86/selftests/pkeys: fork() to check for state being preserved Dave Hansen
2018-10-26 19:59 ` [PATCH 1/2] x86/pkeys: copy pkey state at fork() Dave Hansen
2018-10-26 21:39   ` Daniel Micay
2018-10-26 22:12     ` Andy Lutomirski
2018-10-26 22:56       ` Daniel Micay
2018-10-29  6:36         ` Ingo Molnar
2018-10-29  8:55           ` Daniel Micay [this message]
2018-11-20 21:14   ` Kees Cook
2019-01-09  0:56     ` Kees Cook

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