From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935002AbbCPPut (ORCPT ); Mon, 16 Mar 2015 11:50:49 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:54888 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932397AbbCPOOK (ORCPT ); Mon, 16 Mar 2015 10:14:10 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, James Hogan , Paolo Bonzini , Ralf Baechle , Marcelo Tosatti , Gleb Natapov , Steven Rostedt , Ingo Molnar , linux-mips@linux-mips.org, kvm@vger.kernel.org Subject: [PATCH 3.19 076/177] KVM: MIPS: Fix trace event to save PC directly Date: Mon, 16 Mar 2015 15:08:03 +0100 Message-Id: <20150316140816.558607727@linuxfoundation.org> X-Mailer: git-send-email 2.3.3 In-Reply-To: <20150316140813.085032723@linuxfoundation.org> References: <20150316140813.085032723@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: James Hogan commit b3cffac04eca9af46e1e23560a8ee22b1bd36d43 upstream. Currently the guest exit trace event saves the VCPU pointer to the structure, and the guest PC is retrieved by dereferencing it when the event is printed rather than directly from the trace record. This isn't safe as the printing may occur long afterwards, after the PC has changed and potentially after the VCPU has been freed. Usually this results in the same (wrong) PC being printed for multiple trace events. It also isn't portable as userland has no way to access the VCPU data structure when interpreting the trace record itself. Lets save the actual PC in the structure so that the correct value is accessible later. Fixes: 669e846e6c4e ("KVM/MIPS32: MIPS arch specific APIs for KVM") Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: Ralf Baechle Cc: Marcelo Tosatti Cc: Gleb Natapov Cc: Steven Rostedt Cc: Ingo Molnar Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Acked-by: Steven Rostedt Signed-off-by: Marcelo Tosatti Signed-off-by: Greg Kroah-Hartman --- arch/mips/kvm/trace.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/arch/mips/kvm/trace.h +++ b/arch/mips/kvm/trace.h @@ -24,18 +24,18 @@ TRACE_EVENT(kvm_exit, TP_PROTO(struct kvm_vcpu *vcpu, unsigned int reason), TP_ARGS(vcpu, reason), TP_STRUCT__entry( - __field(struct kvm_vcpu *, vcpu) + __field(unsigned long, pc) __field(unsigned int, reason) ), TP_fast_assign( - __entry->vcpu = vcpu; + __entry->pc = vcpu->arch.pc; __entry->reason = reason; ), TP_printk("[%s]PC: 0x%08lx", kvm_mips_exit_types_str[__entry->reason], - __entry->vcpu->arch.pc) + __entry->pc) ); #endif /* _TRACE_KVM_H */