[Xen-changelog] [qemu-upstream-unstable] chardev: fix pty_chr_timer

[patchbot@xxxxxxx]

commit 4b5b4721464495fe76fe6e2e033cbb61dce78eef
Author:     Gerd Hoffmann <kraxel@xxxxxxxxxx>
AuthorDate: Thu Aug 22 11:43:58 2013 +0200
Commit:     Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
CommitDate: Tue Sep 24 22:52:23 2013 -0500

    chardev: fix pty_chr_timer
    
    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@xxxxxxxxxx
    Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
    (cherry picked from commit b0d768c35e08d2057b63e8e77e7a513c447199fa)
    
    Signed-off-by: Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
---
 qemu-char.c |   12 ++++--------
 1 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/qemu-char.c b/qemu-char.c
index 1be1cf6..1621fbd 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -1026,15 +1026,11 @@ 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;
 }
 
--
generated by git-patchbot for /home/xen/git/qemu-upstream-unstable.git

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