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From: Peter Zijlstra <peterz@infradead.org>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Cc: Peter Anvin <hpa@zytor.com>, Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>,
	Jeremy Fitzhardinge <jeremy@goop.org>,
	Chris Wright <chrisw@sous-sol.org>,
	Alok Kataria <akataria@vmware.com>,
	Rusty Russell <rusty@rustcorp.com.au>,
	virtualization@lists.linux-foundation.org,
	Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	kernel test robot <xiaolong.ye@intel.com>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>
Subject: [PATCH 1/2] x86,paravirt: Fix native_patch()
Date: Thu, 08 Dec 2016 16:42:14 +0100	[thread overview]
Message-ID: <20161208154349.270616999@infradead.org> (raw)
In-Reply-To: 20161208154213.952687487@infradead.org

[-- Attachment #1: peter_zijlstra-fd6f48529f-_aim7_jobs-per-min_-26_1__regression.patch --]
[-- Type: text/plain, Size: 1715 bytes --]

While chasing a regression I noticed we potentially patch the wrong
code in native_patch().

If we do not select the native code sequence, we must use the default
patcher, not fall-through the switch case.

Fixes: 3cded4179481 ("x86/paravirt: Optimize native pv_lock_ops.vcpu_is_preempted()")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/kernel/paravirt_patch_32.c |    4 ++++
 arch/x86/kernel/paravirt_patch_64.c |    4 ++++
 2 files changed, 8 insertions(+)

--- a/arch/x86/kernel/paravirt_patch_32.c
+++ b/arch/x86/kernel/paravirt_patch_32.c
@@ -56,15 +56,19 @@ unsigned native_patch(u8 type, u16 clobb
 				end   = end_pv_lock_ops_queued_spin_unlock;
 				goto patch_site;
 			}
+			goto patch_default;
+
 		case PARAVIRT_PATCH(pv_lock_ops.vcpu_is_preempted):
 			if (pv_is_native_vcpu_is_preempted()) {
 				start = start_pv_lock_ops_vcpu_is_preempted;
 				end   = end_pv_lock_ops_vcpu_is_preempted;
 				goto patch_site;
 			}
+			goto patch_default;
 #endif
 
 	default:
+patch_default:
 		ret = paravirt_patch_default(type, clobbers, ibuf, addr, len);
 		break;
 
--- a/arch/x86/kernel/paravirt_patch_64.c
+++ b/arch/x86/kernel/paravirt_patch_64.c
@@ -68,15 +68,19 @@ unsigned native_patch(u8 type, u16 clobb
 				end   = end_pv_lock_ops_queued_spin_unlock;
 				goto patch_site;
 			}
+			goto patch_default;
+
 		case PARAVIRT_PATCH(pv_lock_ops.vcpu_is_preempted):
 			if (pv_is_native_vcpu_is_preempted()) {
 				start = start_pv_lock_ops_vcpu_is_preempted;
 				end   = end_pv_lock_ops_vcpu_is_preempted;
 				goto patch_site;
 			}
+			goto patch_default;
 #endif
 
 	default:
+patch_default:
 		ret = paravirt_patch_default(type, clobbers, ibuf, addr, len);
 		break;
 

  reply	other threads:[~2016-12-08 15:47 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-08 15:42 [PATCH 0/2] Fix paravirt fail Peter Zijlstra
2016-12-08 15:42 ` Peter Zijlstra [this message]
2016-12-12  6:49   ` [tip:locking/core] x86/paravirt: Fix native_patch() tip-bot for Peter Zijlstra
2016-12-08 15:42 ` [PATCH 2/2] x86, paravirt: Fix bool return type for PVOP_CALL Peter Zijlstra
2016-12-08 16:40   ` Pan Xinhui
2016-12-08 16:50     ` Peter Zijlstra
2016-12-12  6:50   ` [tip:locking/core] x86/paravirt: Fix bool return type for PVOP_CALL() tip-bot for Peter Zijlstra

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