From: Sasha Levin <sashal@kernel.org>
To: gregkh@linuxfoundation.org
Cc: asteinhauser@google.com, tglx@linutronix.de, stable@vger.kernel.org
Subject: Re: FAILED: patch "[PATCH] x86/speculation: PR_SPEC_FORCE_DISABLE enforcement for" failed to apply to 4.19-stable tree
Date: Mon, 15 Jun 2020 14:57:33 -0400 [thread overview]
Message-ID: <20200615185733.GH5492@sasha-vm> (raw)
In-Reply-To: <159222803512332@kroah.com>
On Mon, Jun 15, 2020 at 03:33:55PM +0200, gregkh@linuxfoundation.org wrote:
>
>The patch below does not apply to the 4.19-stable tree.
>If someone wants it applied there, or to any other stable or longterm
>tree, then please email the backport, including the original git commit
>id to <stable@vger.kernel.org>.
>
>thanks,
>
>greg k-h
>
>------------------ original commit in Linus's tree ------------------
>
>From 4d8df8cbb9156b0a0ab3f802b80cb5db57acc0bf Mon Sep 17 00:00:00 2001
>From: Anthony Steinhauser <asteinhauser@google.com>
>Date: Sun, 7 Jun 2020 05:44:19 -0700
>Subject: [PATCH] x86/speculation: PR_SPEC_FORCE_DISABLE enforcement for
> indirect branches.
>
>Currently, it is possible to enable indirect branch speculation even after
>it was force-disabled using the PR_SPEC_FORCE_DISABLE option. Moreover, the
>PR_GET_SPECULATION_CTRL command gives afterwards an incorrect result
>(force-disabled when it is in fact enabled). This also is inconsistent
>vs. STIBP and the documention which cleary states that
>PR_SPEC_FORCE_DISABLE cannot be undone.
>
>Fix this by actually enforcing force-disabled indirect branch
>speculation. PR_SPEC_ENABLE called after PR_SPEC_FORCE_DISABLE now fails
>with -EPERM as described in the documentation.
>
>Fixes: 9137bb27e60e ("x86/speculation: Add prctl() control for indirect branch speculation")
>Signed-off-by: Anthony Steinhauser <asteinhauser@google.com>
>Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
>Cc: stable@vger.kernel.org
This patch now applies fine to all branches after we resolved the issues
with the other IPBP patch.
--
Thanks,
Sasha
prev parent reply other threads:[~2020-06-15 18:57 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-15 13:33 FAILED: patch "[PATCH] x86/speculation: PR_SPEC_FORCE_DISABLE enforcement for" failed to apply to 4.19-stable tree gregkh
2020-06-15 18:57 ` Sasha Levin [this message]
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