Patch "Use WARN_ON_ONCE for missing X86_FEATURE_NRIPS" has been added to the 3.14-stable tree
Subsystems (3)
This is a note to let you know that I've just added the patch titled
Use WARN_ON_ONCE for missing X86_FEATURE_NRIPS
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
use-warn_on_once-for-missing-x86_feature_nrips.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.
Quoted 1 line
From
d2922422c48df93f3edff7d872ee4f3191fefb08Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dirk=20M=C3=BCller?= <[email protected]>
Date: Thu, 1 Oct 2015 13:43:42 +0200
Subject: Use WARN_ON_ONCE for missing X86_FEATURE_NRIPS
From: =?UTF-8?q?Dirk=20M=C3=BCller?= <[email protected]>
commit d2922422c48df93f3edff7d872ee4f3191fefb08 upstream.
The cpu feature flags are not ever going to change, so warning everytime can cause a lot of kernel log spam
(in our case more than 10GB/hour).
The warning seems to only occur when nested virtualization is enabled, so it's probably triggered by a KVM bug. This is a sensible and safe change anyway, and the KVM bug fix might not be suitable for stable releases anyway.
--- arch/x86/kvm/svm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
arch/x86/kvm/svm.c +1 -1
@@ -496,7 +496,7 @@ static void skip_emulated_instruction(ststruct vcpu_svm *svm =to_svm (vcpu);if (svm->vmcb->control.next_rip !=0 ) { -WARN_ON (!static_cpu_has (X86_FEATURE_NRIPS )); +WARN_ON_ONCE (!static_cpu_has (X86_FEATURE_NRIPS )); svm->next_rip = svm->vmcb->control.next_rip; }
Patches currently in stable-queue which might be from [email protected] are
queue-3.14/use-warn_on_once-for-missing-x86_feature_nrips.patch