From 4e4b57342e14f260ca6e2d4cfcbafb876d227909 Mon Sep 17 00:00:00 2001
From: Peter Xu <peterx@redhat.com>
Date: Thu, 18 Jan 2018 13:20:49 +0800
Subject: [PATCH] chardev: fix incorrect unref of source
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glib reported error when pty chardev used:

$ ./qemu-system-x86_64 -chardev pty,id=foo -device isa-serial,chardev=foo
qemu-system-x86_64: -chardev pty,id=foo: char device redirected to /dev/pts/2 (label foo)
(qemu-system-x86_64:27885): GLib-CRITICAL **: g_source_unref: assertion 'source != NULL' failed
(qemu-system-x86_64:27885): GLib-CRITICAL **: g_source_unref: assertion 'source != NULL' failed

This patch fixes that.

Fixes: 2c716ba150 ("chardev: introduce qemu_chr_timeout_add_ms()")
CC: Paolo Bonzini <pbonzini@redhat.com>
Reported-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180118052049.31119-1-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 chardev/char-pty.c | 48 +++++++++++++++++++++++++---------------------
 1 file changed, 26 insertions(+), 22 deletions(-)

diff --git a/chardev/char-pty.c b/chardev/char-pty.c
index 89315e6807..68fd4e20c3 100644
--- a/chardev/char-pty.c
+++ b/chardev/char-pty.c
@@ -51,23 +51,6 @@ typedef struct {
 static void pty_chr_update_read_handler_locked(Chardev *chr);
 static void pty_chr_state(Chardev *chr, int connected);
 
-static gboolean pty_chr_timer(gpointer opaque)
-{
-    struct Chardev *chr = CHARDEV(opaque);
-    PtyChardev *s = PTY_CHARDEV(opaque);
-
-    qemu_mutex_lock(&chr->chr_write_lock);
-    s->timer_src = NULL;
-    g_source_unref(s->open_source);
-    s->open_source = NULL;
-    if (!s->connected) {
-        /* Next poll ... */
-        pty_chr_update_read_handler_locked(chr);
-    }
-    qemu_mutex_unlock(&chr->chr_write_lock);
-    return FALSE;
-}
-
 static void pty_chr_timer_cancel(PtyChardev *s)
 {
     if (s->timer_src) {
@@ -77,6 +60,31 @@ static void pty_chr_timer_cancel(PtyChardev *s)
     }
 }
 
+static void pty_chr_open_src_cancel(PtyChardev *s)
+{
+    if (s->open_source) {
+        g_source_destroy(s->open_source);
+        g_source_unref(s->open_source);
+        s->open_source = NULL;
+    }
+}
+
+static gboolean pty_chr_timer(gpointer opaque)
+{
+    struct Chardev *chr = CHARDEV(opaque);
+    PtyChardev *s = PTY_CHARDEV(opaque);
+
+    qemu_mutex_lock(&chr->chr_write_lock);
+    pty_chr_timer_cancel(s);
+    pty_chr_open_src_cancel(s);
+    if (!s->connected) {
+        /* Next poll ... */
+        pty_chr_update_read_handler_locked(chr);
+    }
+    qemu_mutex_unlock(&chr->chr_write_lock);
+    return FALSE;
+}
+
 /* Called with chr_write_lock held.  */
 static void pty_chr_rearm_timer(Chardev *chr, int ms)
 {
@@ -195,11 +203,7 @@ static void pty_chr_state(Chardev *chr, int connected)
     PtyChardev *s = PTY_CHARDEV(chr);
 
     if (!connected) {
-        if (s->open_source) {
-            g_source_destroy(s->open_source);
-            g_source_unref(s->open_source);
-            s->open_source = NULL;
-        }
+        pty_chr_open_src_cancel(s);
         remove_fd_in_watch(chr);
         s->connected = 0;
         /* (re-)connect poll interval for idle guests: once per second.