This is a note to let you know that I've just added the patch titled
VMCI: Use threaded irqs instead of tasklets
to my char-misc git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.
If you have any questions about this process, please let me know.
From 3daed6345d5880464f46adab871d208e1baa2f3a Mon Sep 17 00:00:00 2001 From: Vishnu Dasa vdasa@vmware.com Date: Tue, 29 Nov 2022 23:05:11 -0800 Subject: 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: Vishnu Dasa vdasa@vmware.com Suggested-by: Zack Rusin zackr@vmware.com Reported-by: Nadav Amit namit@vmware.com Reported-by: Nathan Chancellor nathan@kernel.org Tested-by: Nathan Chancellor nathan@kernel.org Fixes: 463713eb6164 ("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: Bryan Tan bryantan@vmware.com Reviewed-by: Zack Rusin zackr@vmware.com Link: https://lore.kernel.org/r/20221130070511.46558-1-vdasa@vmware.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/misc/vmw_vmci/vmci_guest.c | 49 ++++++++++++------------------ 1 file changed, 19 insertions(+), 30 deletions(-)
diff --git a/drivers/misc/vmw_vmci/vmci_guest.c b/drivers/misc/vmw_vmci/vmci_guest.c index aa7b05de97dd..4f8d962bb5b2 100644 --- a/drivers/misc/vmw_vmci/vmci_guest.c +++ b/drivers/misc/vmw_vmci/vmci_guest.c @@ -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), - 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", @@ -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