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From 65b9fb19d5853b28b6748963d9e0053429655921 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Wed, 18 Sep 2013 09:53:54 +0200
Subject: [PATCH 01/18] chardev: fix pty_chr_timer

RH-Author: Gerd Hoffmann <kraxel@redhat.com>
Message-id: <1379498034-29529-2-git-send-email-kraxel@redhat.com>
Patchwork-id: 54429
O-Subject: [RHEL-7 qemu-kvm PATCH 1/1] chardev: fix pty_chr_timer
Bugzilla: 994414
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Markus Armbruster <armbru@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

pty_chr_timer first calls pty_chr_update_read_handler(), then clears
timer_tag (because it is a one-shot timer).   This is the wrong order
though.  pty_chr_update_read_handler might re-arm time timer, and the
new timer_tag gets overwitten in that case.

This leads to crashes when unplugging a pty chardev:  pty_chr_close
thinks no timer is running -> timer isn't canceled -> pty_chr_timer gets
called with stale CharDevState -> BOOM.

This patch fixes the ordering.
Kill the pointless goto while being at it.

https://bugzilla.redhat.com/show_bug.cgi?id=994414

Cc: qemu-stable@nongnu.org
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit b0d768c35e08d2057b63e8e77e7a513c447199fa)
---
 qemu-char.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 qemu-char.c |   12 ++++--------
 1 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/qemu-char.c b/qemu-char.c
index 2fb876c..660d758 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -1029,15 +1029,11 @@ static gboolean pty_chr_timer(gpointer opaque)
     struct CharDriverState *chr = opaque;
     PtyCharDriver *s = chr->opaque;
 
-    if (s->connected) {
-        goto out;
-    }
-
-    /* Next poll ... */
-    pty_chr_update_read_handler(chr);
-
-out:
     s->timer_tag = 0;
+    if (!s->connected) {
+        /* Next poll ... */
+        pty_chr_update_read_handler(chr);
+    }
     return FALSE;
 }
 
-- 
1.7.1