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VMCI: Use threaded irqs instead of tasklets
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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: Vishnu Dasa <[email protected]>
Suggested-by: Zack Rusin <[email protected]>
Reported-by: Nadav Amit <[email protected]>
Reported-by: Nathan Chancellor <[email protected]>
Tested-by: Nathan Chancellor <[email protected]>
Fixes: 463713e ("VMCI: dma dg: add support for DMA datagrams receive")
Cc: <[email protected]> # v5.18+
Cc: VMware PV-Drivers Reviewers <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Bryan Tan <[email protected]>
Reviewed-by: Bryan Tan <[email protected]>
Reviewed-by: Zack Rusin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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@vdasahar @gregkh
vdasahar authored and gregkh committed Jan 20, 2023
1 parent aaca766 commit 3daed63
Showing 1 changed file with 19 additions and 30 deletions.
49 changes: 19 additions & 30 deletions drivers/misc/vmw_vmci/vmci_guest.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand All @@ -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;

Expand All @@ -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;
}

Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -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) {
Expand Down Expand Up @@ -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);
Expand All @@ -823,19 +815,21 @@ 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",
pci_irq_vector(pdev, 1), error);
goto err_free_irq;
}
if (caps_in_use & VMCI_CAPS_DMA_DATAGRAM) {
error = request_irq(pci_irq_vector(pdev, 2),
vmci_interrupt_dma_datagram,
0, KBUILD_MODNAME, vmci_dev);
error = request_threaded_irq(pci_irq_vector(pdev, 2),
NULL,
vmci_interrupt_dma_datagram,
0, KBUILD_MODNAME,
vmci_dev);
if (error) {
dev_err(&pdev->dev,
"Failed to allocate irq %u: %d\n",
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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
Expand Down

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