Commit 3daed634 authored by Vishnu Dasa's avatar Vishnu Dasa Committed by Greg Kroah-Hartman
Browse files

VMCI: Use threaded irqs instead of tasklets 



The vmci_dispatch_dgs() tasklet function calls vmci_read_data()
which uses wait_event() resulting in invalid sleep in an atomic
context (and therefore potentially in a deadlock).

Use threaded irqs to fix this issue and completely remove usage
of tasklets.

[   20.264639] BUG: sleeping function called from invalid context at drivers/misc/vmw_vmci/vmci_guest.c:145
[   20.264643] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 762, name: vmtoolsd
[   20.264645] preempt_count: 101, expected: 0
[   20.264646] RCU nest depth: 0, expected: 0
[   20.264647] 1 lock held by vmtoolsd/762:
[   20.264648]  #0: ffff0000874ae440 (sk_lock-AF_VSOCK){+.+.}-{0:0}, at: vsock_connect+0x60/0x330 [vsock]
[   20.264658] Preemption disabled at:
[   20.264659] [<ffff80000151d7d8>] vmci_send_datagram+0x44/0xa0 [vmw_vmci]
[   20.264665] CPU: 0 PID: 762 Comm: vmtoolsd Not tainted 5.19.0-0.rc8.20220727git39c3c396f813.60.fc37.aarch64 #1
[   20.264667] Hardware name: VMware, Inc. VBSA/VBSA, BIOS VEFI 12/31/2020
[   20.264668] Call trace:
[   20.264669]  dump_backtrace+0xc4/0x130
[   20.264672]  show_stack+0x24/0x80
[   20.264673]  dump_stack_lvl+0x88/0xb4
[   20.264676]  dump_stack+0x18/0x34
[   20.264677]  __might_resched+0x1a0/0x280
[   20.264679]  __might_sleep+0x58/0x90
[   20.264681]  vmci_read_data+0x74/0x120 [vmw_vmci]
[   20.264683]  vmci_dispatch_dgs+0x64/0x204 [vmw_vmci]
[   20.264686]  tasklet_action_common.constprop.0+0x13c/0x150
[   20.264688]  tasklet_action+0x40/0x50
[   20.264689]  __do_softirq+0x23c/0x6b4
[   20.264690]  __irq_exit_rcu+0x104/0x214
[   20.264691]  irq_exit_rcu+0x1c/0x50
[   20.264693]  el1_interrupt+0x38/0x6c
[   20.264695]  el1h_64_irq_handler+0x18/0x24
[   20.264696]  el1h_64_irq+0x68/0x6c
[   20.264697]  preempt_count_sub+0xa4/0xe0
[   20.264698]  _raw_spin_unlock_irqrestore+0x64/0xb0
[   20.264701]  vmci_send_datagram+0x7c/0xa0 [vmw_vmci]
[   20.264703]  vmci_datagram_dispatch+0x84/0x100 [vmw_vmci]
[   20.264706]  vmci_datagram_send+0x2c/0x40 [vmw_vmci]
[   20.264709]  vmci_transport_send_control_pkt+0xb8/0x120 [vmw_vsock_vmci_transport]
[   20.264711]  vmci_transport_connect+0x40/0x7c [vmw_vsock_vmci_transport]
[   20.264713]  vsock_connect+0x278/0x330 [vsock]
[   20.264715]  __sys_connect_file+0x8c/0xc0
[   20.264718]  __sys_connect+0x84/0xb4
[   20.264720]  __arm64_sys_connect+0x2c/0x3c
[   20.264721]  invoke_syscall+0x78/0x100
[   20.264723]  el0_svc_common.constprop.0+0x68/0x124
[   20.264724]  do_el0_svc+0x38/0x4c
[   20.264725]  el0_svc+0x60/0x180
[   20.264726]  el0t_64_sync_handler+0x11c/0x150
[   20.264728]  el0t_64_sync+0x190/0x194

Signed-off-by: default avatarVishnu Dasa <vdasa@vmware.com>
Suggested-by: default avatarZack Rusin <zackr@vmware.com>
Reported-by: default avatarNadav Amit <namit@vmware.com>
Reported-by: default avatarNathan Chancellor <nathan@kernel.org>
Tested-by: default avatarNathan Chancellor <nathan@kernel.org>
Fixes: 463713eb ("VMCI: dma dg: add support for DMA datagrams receive")
Cc: <stable@vger.kernel.org> # v5.18+
Cc: VMware PV-Drivers Reviewers <pv-drivers@vmware.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Bryan Tan <bryantan@vmware.com>
Reviewed-by: default avatarBryan Tan <bryantan@vmware.com>
Reviewed-by: default avatarZack Rusin <zackr@vmware.com>
Link: https://lore.kernel.org/r/20221130070511.46558-1-vdasa@vmware.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent aaca766c

drivers/misc/vmw_vmci/vmci_guest.c

+19 −30
Original line number Diff line number Diff line
@@ -56,8 +56,6 @@ struct vmci_guest_device { 


	bool exclusive_vectors;



	struct tasklet_struct datagram_tasklet;

	struct tasklet_struct bm_tasklet;

	struct wait_queue_head inout_wq;



	void *data_buffer;
@@ -304,9 +302,8 @@ static int vmci_check_host_caps(struct pci_dev *pdev) 
 * This function assumes that it has exclusive access to the data

 * in register(s) for the duration of the call.

 */

static void vmci_dispatch_dgs(unsigned long data)

static void vmci_dispatch_dgs(struct vmci_guest_device *vmci_dev)

{

	struct vmci_guest_device *vmci_dev = (struct vmci_guest_device *)data;

	u8 *dg_in_buffer = vmci_dev->data_buffer;

	struct vmci_datagram *dg;

	size_t dg_in_buffer_size = VMCI_MAX_DG_SIZE;
@@ -465,10 +462,8 @@ static void vmci_dispatch_dgs(unsigned long data) 
 * Scans the notification bitmap for raised flags, clears them

 * and handles the notifications.

 */

static void vmci_process_bitmap(unsigned long data)

static void vmci_process_bitmap(struct vmci_guest_device *dev)

{

	struct vmci_guest_device *dev = (struct vmci_guest_device *)data;



	if (!dev->notification_bitmap) {

		dev_dbg(dev->dev, "No bitmap present in %s\n", __func__);

		return;
@@ -486,13 +481,13 @@ static irqreturn_t vmci_interrupt(int irq, void *_dev) 
	struct vmci_guest_device *dev = _dev;



	/*

	 * If we are using MSI-X with exclusive vectors then we simply schedule

	 * the datagram tasklet, since we know the interrupt was meant for us.

	 * If we are using MSI-X with exclusive vectors then we simply call

	 * vmci_dispatch_dgs(), since we know the interrupt was meant for us.

	 * Otherwise we must read the ICR to determine what to do.

	 */



	if (dev->exclusive_vectors) {

		tasklet_schedule(&dev->datagram_tasklet);

		vmci_dispatch_dgs(dev);

	} else {

		unsigned int icr;
@@ -502,12 +497,12 @@ static irqreturn_t vmci_interrupt(int irq, void *_dev) 
			return IRQ_NONE;



		if (icr & VMCI_ICR_DATAGRAM) {

			tasklet_schedule(&dev->datagram_tasklet);

			vmci_dispatch_dgs(dev);

			icr &= ~VMCI_ICR_DATAGRAM;

		}



		if (icr & VMCI_ICR_NOTIFICATION) {

			tasklet_schedule(&dev->bm_tasklet);

			vmci_process_bitmap(dev);

			icr &= ~VMCI_ICR_NOTIFICATION;

		}
@@ -536,7 +531,7 @@ static irqreturn_t vmci_interrupt_bm(int irq, void *_dev) 
	struct vmci_guest_device *dev = _dev;



	/* For MSI-X we can just assume it was meant for us. */

	tasklet_schedule(&dev->bm_tasklet);

	vmci_process_bitmap(dev);



	return IRQ_HANDLED;

}
@@ -638,10 +633,6 @@ static int vmci_guest_probe_device(struct pci_dev *pdev, 
	vmci_dev->iobase = iobase;

	vmci_dev->mmio_base = mmio_base;



	tasklet_init(&vmci_dev->datagram_tasklet,

		     vmci_dispatch_dgs, (unsigned long)vmci_dev);

	tasklet_init(&vmci_dev->bm_tasklet,

		     vmci_process_bitmap, (unsigned long)vmci_dev);

	init_waitqueue_head(&vmci_dev->inout_wq);



	if (mmio_base != NULL) {
@@ -808,8 +799,9 @@ static int vmci_guest_probe_device(struct pci_dev *pdev, 
	 * Request IRQ for legacy or MSI interrupts, or for first

	 * MSI-X vector.

	 */

	error = request_irq(pci_irq_vector(pdev, 0), vmci_interrupt,

			    IRQF_SHARED, KBUILD_MODNAME, vmci_dev);

	error = request_threaded_irq(pci_irq_vector(pdev, 0), NULL,

				     vmci_interrupt, IRQF_SHARED,

				     KBUILD_MODNAME, vmci_dev);

	if (error) {

		dev_err(&pdev->dev, "Irq %u in use: %d\n",

			pci_irq_vector(pdev, 0), error);
@@ -823,9 +815,9 @@ static int vmci_guest_probe_device(struct pci_dev *pdev, 
	 * between the vectors.

	 */

	if (vmci_dev->exclusive_vectors) {

		error = request_irq(pci_irq_vector(pdev, 1),

				    vmci_interrupt_bm, 0, KBUILD_MODNAME,

				    vmci_dev);

		error = request_threaded_irq(pci_irq_vector(pdev, 1), NULL,

					     vmci_interrupt_bm, 0,

					     KBUILD_MODNAME, vmci_dev);

		if (error) {

			dev_err(&pdev->dev,

				"Failed to allocate irq %u: %d\n",
@@ -833,9 +825,11 @@ static int vmci_guest_probe_device(struct pci_dev *pdev, 
			goto err_free_irq;

		}

		if (caps_in_use & VMCI_CAPS_DMA_DATAGRAM) {

			error = request_irq(pci_irq_vector(pdev, 2),

			error = request_threaded_irq(pci_irq_vector(pdev, 2),

						     NULL,

						    vmci_interrupt_dma_datagram,

					    0, KBUILD_MODNAME, vmci_dev);

						     0, KBUILD_MODNAME,

						     vmci_dev);

			if (error) {

				dev_err(&pdev->dev,

					"Failed to allocate irq %u: %d\n",
@@ -871,8 +865,6 @@ static int vmci_guest_probe_device(struct pci_dev *pdev, 


err_free_irq:

	free_irq(pci_irq_vector(pdev, 0), vmci_dev);

	tasklet_kill(&vmci_dev->datagram_tasklet);

	tasklet_kill(&vmci_dev->bm_tasklet);



err_disable_msi:

	pci_free_irq_vectors(pdev);
@@ -943,9 +935,6 @@ static void vmci_guest_remove_device(struct pci_dev *pdev) 
	free_irq(pci_irq_vector(pdev, 0), vmci_dev);

	pci_free_irq_vectors(pdev);



	tasklet_kill(&vmci_dev->datagram_tasklet);

	tasklet_kill(&vmci_dev->bm_tasklet);



	if (vmci_dev->notification_bitmap) {

		/*

		 * The device reset above cleared the bitmap state of the