From 6a40d58e03beaef265f6c1293301f5f8860ecbea Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Thu, 18 May 2017 09:21:22 +0200 Subject: [PATCH 09/18] qemu-char: ignore flow control if a PTY's slave is not connected RH-Author: Fam Zheng Message-id: <20170518092131.16571-10-famz@redhat.com> Patchwork-id: 75301 O-Subject: [RHEL-7.4 qemu-kvm PATCH v3 09/18] qemu-char: ignore flow control if a PTY's slave is not connected Bugzilla: 1451470 RH-Acked-by: Paolo Bonzini RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Eduardo Habkost From: Paolo Bonzini After commit f702e62 (serial: change retry logic to avoid concurrency, 2014-07-11), guest boot hangs if the backend is an unconnected PTY. The reason is that PTYs do not support G_IO_HUP, and serial_xmit is never called. To fix this, simply invoke serial_xmit immediately (via g_idle_source_new) when this happens. Tested-by: Pavel Hrdina Signed-off-by: Paolo Bonzini (cherry picked from commit 62c339c5272ce8fbe8ca52695cee8ff40da7872e) Signed-off-by: Fam Zheng Signed-off-by: Miroslav Rezanina --- qemu-char.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/qemu-char.c b/qemu-char.c index 47ac55a..08cb959 100644 --- a/qemu-char.c +++ b/qemu-char.c @@ -1068,6 +1068,9 @@ static int pty_chr_write(CharDriverState *chr, const uint8_t *buf, int len) static GSource *pty_chr_add_watch(CharDriverState *chr, GIOCondition cond) { PtyCharDriver *s = chr->opaque; + if (!s->connected) { + return NULL; + } return g_io_create_watch(s->fd, cond); } @@ -3381,6 +3384,10 @@ int qemu_chr_fe_add_watch(CharDriverState *s, GIOCondition cond, } src = s->chr_add_watch(s, cond); + if (!src) { + return -EINVAL; + } + g_source_set_callback(src, (GSourceFunc)func, user_data, NULL); tag = g_source_attach(src, NULL); g_source_unref(src); -- 1.8.3.1