From b4927bd272623694314f37823302f9d67aa5964c Mon Sep 17 00:00:00 2001 From: Andrea Parri (Microsoft) Date: Thu, 12 May 2022 00:32:07 +0200 Subject: PCI: hv: Fix synchronization between channel callback and hv_pci_bus_exit() [ Similarly to commit a765ed47e4516 ("PCI: hv: Fix synchronization between channel callback and hv_compose_msi_msg()"): ] The (on-stack) teardown packet becomes invalid once the completion timeout in hv_pci_bus_exit() has expired and hv_pci_bus_exit() has returned. Prevent the channel callback from accessing the invalid packet by removing the ID associated to such packet from the VMbus requestor in hv_pci_bus_exit(). Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Michael Kelley Acked-by: Lorenzo Pieralisi Link: https://lore.kernel.org/r/20220511223207.3386-3-parri.andrea@gmail.com Signed-off-by: Wei Liu --- drivers/pci/controller/pci-hyperv.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index a06e2cf94658..db814f7b93ba 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -3664,6 +3664,7 @@ free_bus: static int hv_pci_bus_exit(struct hv_device *hdev, bool keep_devs) { struct hv_pcibus_device *hbus = hv_get_drvdata(hdev); + struct vmbus_channel *chan = hdev->channel; struct { struct pci_packet teardown_packet; u8 buffer[sizeof(struct pci_message)]; @@ -3671,13 +3672,14 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool keep_devs) struct hv_pci_compl comp_pkt; struct hv_pci_dev *hpdev, *tmp; unsigned long flags; + u64 trans_id; int ret; /* * After the host sends the RESCIND_CHANNEL message, it doesn't * access the per-channel ringbuffer any longer. */ - if (hdev->channel->rescind) + if (chan->rescind) return 0; if (!keep_devs) { @@ -3714,16 +3716,26 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool keep_devs) pkt.teardown_packet.compl_ctxt = &comp_pkt; pkt.teardown_packet.message[0].type = PCI_BUS_D0EXIT; - ret = vmbus_sendpacket(hdev->channel, &pkt.teardown_packet.message, - sizeof(struct pci_message), - (unsigned long)&pkt.teardown_packet, - VM_PKT_DATA_INBAND, - VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); + ret = vmbus_sendpacket_getid(chan, &pkt.teardown_packet.message, + sizeof(struct pci_message), + (unsigned long)&pkt.teardown_packet, + &trans_id, VM_PKT_DATA_INBAND, + VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); if (ret) return ret; - if (wait_for_completion_timeout(&comp_pkt.host_event, 10 * HZ) == 0) + if (wait_for_completion_timeout(&comp_pkt.host_event, 10 * HZ) == 0) { + /* + * The completion packet on the stack becomes invalid after + * 'return'; remove the ID from the VMbus requestor if the + * identifier is still mapped to/associated with the packet. + * + * Cf. hv_pci_onchannelcallback(). + */ + vmbus_request_addr_match(chan, trans_id, + (unsigned long)&pkt.teardown_packet); return -ETIMEDOUT; + } return 0; } -- cgit v1.2.3