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authorAmit Shah <amit.shah@redhat.com>2013-08-28 15:24:05 +0530
committerAmit Shah <amit.shah@redhat.com>2013-09-05 18:30:36 +0530
commit386a5a1e0057e220f79c48fe3689e3dfb17f1b09 (patch)
treec65829a5be0be6978005dc0047ffbbc0533f7497 /qemu-char.c
parent26da70c72524eb22c946ab19ec98a217b8252f7e (diff)
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char: remove watch callback on chardev detach from frontend
If a frontend device releases the chardev (via unplug), the chr handlers are set to NULL via qdev's exit callbacks invoking qemu_chr_add_handlers(). If the chardev had a pending operation, a callback will be invoked, which will try to access data in the just-released frontend, causing a segfault. Ensure the callbacks are disabled when frontends release chardevs. This was seen when a virtio-serial port was unplugged when heavy guest->host IO was in progress (causing a callback to be registered). In the window in which the throttling was active, unplugging ports caused a qemu segfault. https://bugzilla.redhat.com/show_bug.cgi?id=985205 CC: <qemu-stable@nongnu.org> Reported-by: Sibiao Luo <sluo@redhat.com> Reviewed-by: Gerd Hoffmann <kraxel@redhat.com> Signed-off-by: Amit Shah <amit.shah@redhat.com>
Diffstat (limited to 'qemu-char.c')
-rw-r--r--qemu-char.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/qemu-char.c b/qemu-char.c
index 0a0833f..6f111ab 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -193,6 +193,8 @@ void qemu_chr_fe_printf(CharDriverState *s, const char *fmt, ...)
va_end(ap);
}
+static void remove_fd_in_watch(CharDriverState *chr);
+
void qemu_chr_add_handlers(CharDriverState *s,
IOCanReadHandler *fd_can_read,
IOReadHandler *fd_read,
@@ -203,6 +205,7 @@ void qemu_chr_add_handlers(CharDriverState *s,
if (!opaque && !fd_can_read && !fd_read && !fd_event) {
fe_open = 0;
+ remove_fd_in_watch(s);
} else {
fe_open = 1;
}