From 3f937c82256585da1abba44c4600b96b0b186df4 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Fri, 6 Jul 2018 17:56:53 +0200
Subject: [PATCH 193/268] pr-manager-helper: avoid SIGSEGV when writing to the
 socket fail

RH-Author: Paolo Bonzini <pbonzini@redhat.com>
Message-id: <20180706175659.30615-4-pbonzini@redhat.com>
Patchwork-id: 81245
O-Subject: [RHEL7.6 qemu-kvm-rhev PATCH 3/9] pr-manager-helper: avoid SIGSEGV when writing to the socket fail
Bugzilla: 1533158
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Michal Privoznik <mprivozn@redhat.com>

When writing to the qemu-pr-helper socket failed, the persistent
reservation manager was correctly disconnecting the socket, but it
did not clear pr_mgr->ioc.  So the rest of the code did not know
that the socket had been disconnected, accessed pr_mgr->ioc and
happily caused a crash.

To reproduce, it is enough to stop qemu-pr-helper between QEMU
startup and executing e.g. sg_persist -k /dev/sdb.

Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit aad10040d411d21542dc9ae58a2854c89ccedd78)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 scsi/pr-manager-helper.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/scsi/pr-manager-helper.c b/scsi/pr-manager-helper.c
index 82ff6b6..0c0fe38 100644
--- a/scsi/pr-manager-helper.c
+++ b/scsi/pr-manager-helper.c
@@ -71,6 +71,7 @@ static int pr_manager_helper_write(PRManagerHelper *pr_mgr,
         if (n_written <= 0) {
             assert(n_written != QIO_CHANNEL_ERR_BLOCK);
             object_unref(OBJECT(pr_mgr->ioc));
+            pr_mgr->ioc = NULL;
             return n_written < 0 ? -EINVAL : 0;
         }
 
-- 
1.8.3.1