From 05af6159ba18882c0bdef512abd3c852b515430b Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann Date: Wed, 13 Jun 2018 14:07:30 +0200 Subject: [PATCH 03/57] usb-host: skip open on pending postload bh RH-Author: Gerd Hoffmann Message-id: <20180613140730.16401-2-kraxel@redhat.com> Patchwork-id: 80667 O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH 1/1] usb-host: skip open on pending postload bh Bugzilla: 1572851 RH-Acked-by: Dr. David Alan Gilbert RH-Acked-by: Laszlo Ersek RH-Acked-by: Laurent Vivier usb-host emulates a device unplug after live migration, because the device state is unknown and unplug/replug makes sure the guest re-initializes the device into a working state. This can't be done in post-load though, so post-load just schedules a bottom half which executes after vmload is complete. It can happen that the device autoscan timer hits the race window between scheduling and running the bottom half, which in turn can triggers an assert(). Fix that issue by just ignoring the usb_host_open() call in case the bottom half didn't execute yet. Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1572851 Signed-off-by: Gerd Hoffmann Message-id: 20180503062932.17233-1-kraxel@redhat.com (cherry picked from commit 3280ea8edede3814553aa19fa27a58daedd48ad9) Signed-off-by: Miroslav Rezanina --- hw/usb/host-libusb.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/hw/usb/host-libusb.c b/hw/usb/host-libusb.c index 1b0be07..0290fb8 100644 --- a/hw/usb/host-libusb.c +++ b/hw/usb/host-libusb.c @@ -102,6 +102,7 @@ struct USBHostDevice { /* callbacks & friends */ QEMUBH *bh_nodev; QEMUBH *bh_postld; + bool bh_postld_pending; Notifier exit; /* request queues */ @@ -866,6 +867,10 @@ static int usb_host_open(USBHostDevice *s, libusb_device *dev) int rc; Error *local_err = NULL; + if (s->bh_postld_pending) { + return -1; + } + trace_usb_host_open_started(bus_num, addr); if (s->dh != NULL) { @@ -1524,6 +1529,7 @@ static void usb_host_post_load_bh(void *opaque) if (udev->attached) { usb_device_detach(udev); } + dev->bh_postld_pending = false; usb_host_auto_check(NULL); } @@ -1535,6 +1541,7 @@ static int usb_host_post_load(void *opaque, int version_id) dev->bh_postld = qemu_bh_new(usb_host_post_load_bh, dev); } qemu_bh_schedule(dev->bh_postld); + dev->bh_postld_pending = true; return 0; } -- 1.8.3.1