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From: "Michael S. Tsirkin" <mst@redhat.com>
To: qemu-devel@nongnu.org
Cc: Peter Maydell <peter.maydell@linaro.org>,
	Yuri Benditovich <yuri.benditovich@daynix.com>
Subject: [PULL 4/9] virtio-pci: add check for vdev in virtio_pci_isr_read
Date: Thu, 1 Apr 2021 14:03:00 -0400	[thread overview]
Message-ID: <20210401180235.226321-5-mst@redhat.com> (raw)
In-Reply-To: <20210401180235.226321-1-mst@redhat.com>

From: Yuri Benditovich <yuri.benditovich@daynix.com>

https://bugzilla.redhat.com/show_bug.cgi?id=1743098
This commit completes the solution of segfault in hot unplug flow
(by commit ccec7e9603f446fe75c6c563ba335c00cfda6a06).
Added missing check for vdev in virtio_pci_isr_read.
Typical stack of crash:
virtio_pci_isr_read ../hw/virtio/virtio-pci.c:1365 with proxy-vdev = 0
memory_region_read_accessor at ../softmmu/memory.c:442
access_with_adjusted_size at ../softmmu/memory.c:552
memory_region_dispatch_read1 at ../softmmu/memory.c:1420
memory_region_dispatch_read  at ../softmmu/memory.c:1449
flatview_read_continue at ../softmmu/physmem.c:2822
flatview_read at ../softmmu/physmem.c:2862
address_space_read_full at ../softmmu/physmem.c:2875

Signed-off-by: Yuri Benditovich <yuri.benditovich@daynix.com>
Message-Id: <20210315115937.14286-2-yuri.benditovich@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/virtio/virtio-pci.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 883045a223..4a3dcee771 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1364,9 +1364,14 @@ static uint64_t virtio_pci_isr_read(void *opaque, hwaddr addr,
 {
     VirtIOPCIProxy *proxy = opaque;
     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
-    uint64_t val = qatomic_xchg(&vdev->isr, 0);
-    pci_irq_deassert(&proxy->pci_dev);
+    uint64_t val;
 
+    if (vdev == NULL) {
+        return 0;
+    }
+
+    val = qatomic_xchg(&vdev->isr, 0);
+    pci_irq_deassert(&proxy->pci_dev);
     return val;
 }
 
-- 
MST



  parent reply	other threads:[~2021-04-01 18:11 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-01 18:02 [PULL 0/9] pc,virtio,pci: bugfixes Michael S. Tsirkin
2021-04-01 18:02 ` [PULL 1/9] vhost-user-blk: use different event handlers on initialization Michael S. Tsirkin
2021-04-01 18:02 ` [PULL 2/9] vhost-user-blk: perform immediate cleanup if disconnect " Michael S. Tsirkin
2021-04-01 18:02 ` [PULL 3/9] vhost-user-blk: add immediate cleanup on shutdown Michael S. Tsirkin
2021-04-01 18:03 ` Michael S. Tsirkin [this message]
2021-04-01 18:03 ` [PULL 5/9] virtio-pci: remove explicit initialization of val Michael S. Tsirkin
2021-04-01 18:03 ` [PULL 6/9] acpi/piix4: reinitialize acpi PM device on reset Michael S. Tsirkin
2021-04-01 18:03 ` [PULL 7/9] vt82c686.c: don't raise SCI when PCI_INTERRUPT_PIN isn't setup Michael S. Tsirkin
2021-04-01 18:03 ` [PULL 8/9] isa/v582c686: Reinitialize ACPI PM device on reset Michael S. Tsirkin
2021-04-01 18:03 ` [PULL 9/9] pci: sprinkle assert in PCI pin number Michael S. Tsirkin
2021-04-04 20:47 ` [PULL 0/9] pc,virtio,pci: bugfixes Peter Maydell

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