i386: avoid null pointer dereference
commit4c1396cb576c9b14425558b73de1584c7a9735d7
authorP J P <ppandit@redhat.com>
Fri, 18 Dec 2015 06:05:07 +0000 (18 11:35 +0530)
committerPaolo Bonzini <pbonzini@redhat.com>
Fri, 15 Jan 2016 17:58:01 +0000 (15 18:58 +0100)
tree8f15067c7bce14a79411ff188dd2ea8c2e9e5a86
parent76c64d33601a4948d6f72022992574a75b6fab97
i386: avoid null pointer dereference

    Hello,

A null pointer dereference issue was reported by Mr Ling Liu, CC'd here. It
occurs while doing I/O port write operations via hmp interface. In that,
'current_cpu' remains null as it is not called from cpu_exec loop, which
results in the said issue.

Below is a proposed (tested)patch to fix this issue; Does it look okay?

===
From ae88a4947fab9a148cd794f8ad2d812e7f5a1d0f Mon Sep 17 00:00:00 2001
From: Prasad J Pandit <pjp@fedoraproject.org>
Date: Fri, 18 Dec 2015 11:16:07 +0530
Subject: [PATCH] i386: avoid null pointer dereference

When I/O port write operation is called from hmp interface,
'current_cpu' remains null, as it is not called from cpu_exec()
loop. This leads to a null pointer dereference in vapic_write
routine. Add check to avoid it.

Reported-by: Ling Liu <liuling-it@360.cn>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Message-Id: <alpine.LFD.2.20.1512181129320.9805@wniryva>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: P J P <ppandit@redhat.com>
hw/i386/kvmvapic.c