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From 65b9fb19d5853b28b6748963d9e0053429655921 Mon Sep 17 00:00:00 2001
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From: Gerd Hoffmann <kraxel@redhat.com>
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Date: Wed, 18 Sep 2013 09:53:54 +0200
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Subject: [PATCH 01/18] chardev: fix pty_chr_timer
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RH-Author: Gerd Hoffmann <kraxel@redhat.com>
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Message-id: <1379498034-29529-2-git-send-email-kraxel@redhat.com>
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Patchwork-id: 54429
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O-Subject: [RHEL-7 qemu-kvm PATCH 1/1] chardev: fix pty_chr_timer
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Bugzilla: 994414
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Markus Armbruster <armbru@redhat.com>
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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pty_chr_timer first calls pty_chr_update_read_handler(), then clears
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timer_tag (because it is a one-shot timer).   This is the wrong order
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though.  pty_chr_update_read_handler might re-arm time timer, and the
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new timer_tag gets overwitten in that case.
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This leads to crashes when unplugging a pty chardev:  pty_chr_close
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thinks no timer is running -> timer isn't canceled -> pty_chr_timer gets
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called with stale CharDevState -> BOOM.
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This patch fixes the ordering.
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Kill the pointless goto while being at it.
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https://bugzilla.redhat.com/show_bug.cgi?id=994414
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Cc: qemu-stable@nongnu.org
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Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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(cherry picked from commit b0d768c35e08d2057b63e8e77e7a513c447199fa)
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---
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 qemu-char.c | 12 ++++--------
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 1 file changed, 4 insertions(+), 8 deletions(-)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 qemu-char.c |   12 ++++--------
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 1 files changed, 4 insertions(+), 8 deletions(-)
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diff --git a/qemu-char.c b/qemu-char.c
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index 2fb876c..660d758 100644
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--- a/qemu-char.c
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+++ b/qemu-char.c
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@@ -1029,15 +1029,11 @@ static gboolean pty_chr_timer(gpointer opaque)
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     struct CharDriverState *chr = opaque;
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     PtyCharDriver *s = chr->opaque;
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-    if (s->connected) {
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-        goto out;
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-    }
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-
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-    /* Next poll ... */
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-    pty_chr_update_read_handler(chr);
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-
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-out:
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     s->timer_tag = 0;
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+    if (!s->connected) {
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+        /* Next poll ... */
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+        pty_chr_update_read_handler(chr);
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+    }
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     return FALSE;
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 }
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-- 
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1.7.1
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