kernel/git/next/linux-next.git/drivers/virtio, branch stable

virtio_input: stop callbacks before unregistering input device

2026-09-07T22:54:04+00:00

virtinput_remove() unregisters the input device before resetting the virtio device. virtinput_recv_events() drops vi->lock around input_event(), so clearing vi->ready does not stop a callback that passed the entry check. It can still use vi->idev, requeue buffers and kick the queue. Reset first, as virtinput_freeze() already does. With the preceding core change, reset waits for callbacks before input_unregister_device() can free vi->idev. Recheck vi->ready after taking the lock again: keep draining completed events so an input packet is not truncated, but stop requeueing buffers and kicking the queue. With evdev attached, input_unregister_handle() currently waits for an RCU grace period, which also waits out IRQ callbacks. This masks the lifetime bug on PCI and MMIO, but does not protect sleepable callbacks on other transports. Fixes: 271c865161c5 ("Add virtio-input driver.") Assisted-by: LLM Signed-off-by: Karl Mehltretter Signed-off-by: Michael S. Tsirkin Message-ID: <20260905152059.89560-3-kmehltretter@gmail.com>

virtio_input: reset device if input_register_device() fails

2026-09-07T22:54:04+00:00

Probe marks the device DRIVER_OK with virtio_device_ready() before calling input_register_device(). If registration fails, the error path cleared vi->ready and called del_vqs() while the device was still live, so the device could keep DMA to queues that were already torn down. Match remove/freeze: call virtio_reset_device() on that path before tearing down the virtqueues. Fixes: 271c865161c5 ("Add virtio-input driver.") Signed-off-by: Xiong Weimin Signed-off-by: Michael S. Tsirkin Message-ID: <20260805032931.1606652-1-xiongweimin@kylinos.cn>

virtio-pci: return IRQ_HANDLED after non-zero ISR

2026-09-07T22:54:03+00:00

vp_interrupt() reads the ISR before dispatching config-change and vring handling. Reading the ISR also clears it, so once the read returns non-zero the interrupt was from this device and has already been consumed. Currently vp_interrupt() returns the result of vp_vring_interrupt(). For a config-change interrupt with no vring work, that can return IRQ_NONE even though the ISR was non-zero and the interrupt was handled. Call vp_vring_interrupt() for any queue work, but once the ISR is non-zero return IRQ_HANDLED. Tested with QEMU virtio-blk-pci forced to INTx using vectors=0 and pci=nomsi. On an idle device, 200 config-change interrupts were generated using QMP block_resize. Before this change, irq_handler_exit reported ret=unhandled and /proc/irq/11/spurious increased from 0 to 200 unhandled interrupts. After this change, irq_handler_exit reported ret=handled and the unhandled count remained at 0. The issue was found during an LLM-assisted Quality Playbook review. Fixes: 77cf524654a8 ("virtio_pci: split up vp_interrupt") Suggested-by: Michael S. Tsirkin Assisted-by: LLM Signed-off-by: Andrew Stellman Message-ID: <20260904141318.30278-1-astellman@stellman-greene.com> Signed-off-by: Michael S. Tsirkin

virtio-vdpa: Use queue id when setting vq affinity

2026-09-07T22:54:03+00:00

When optional queues are skipped, pass the compressed vDPA queue id to set_vq_affinity() so affinity is applied to the queue that was actually created. Signed-off-by: Xiong Weimin Signed-off-by: Michael S. Tsirkin Message-ID: <20260804092649.1344478-1-xiongweimin@kylinos.cn>

virtio_mmio: disable IRQ wake before free_irq

2026-09-07T22:54:02+00:00

When the DT node has "wakeup-source", vm_find_vqs() calls enable_irq_wake() on the shared IRQ, but vm_del_vqs() freed that IRQ without a matching disable_irq_wake(). That leaves a wake reference behind and can warn on later free_irq()/request_irq() cycles. Record whether enable_irq_wake() succeeded, and disable it in vm_del_vqs() before free_irq(). Fixes: 02213273f72a ("virtio_mmio: add support to set IRQ of a virtio device as wakeup source") Cc: stable@vger.kernel.org Signed-off-by: Xiong Weimin Signed-off-by: Michael S. Tsirkin Message-ID: <20260805032937.1606737-1-xiongweimin@kylinos.cn>

virtio: fix use-after-free in unregister_virtio_device()

2026-09-07T22:54:02+00:00

device_unregister() is device_del() plus put_device(). When the caller holds no extra reference, that drops the last one and runs the release callback, which for several transports frees the memory the embedded struct virtio_device sits in. unregister_virtio_device() then calls virtio_debug_device_exit(), which reads dev->debugfs_dir out of the freed object. Affected transports are the ones whose release callback frees and whose remove path takes no reference: virtio_mmio, virtio_vdpa, virtio_uml, mlxbf-tmfifo and virtio_ccw. virtio_pci is unaffected because virtio_pci_remove() brackets the call with get_device() and put_device(). Remove the debugfs entries before the device can go away. They are only accessed through the protected debugfs interface, so debugfs_remove_recursive() waits for in-progress file operations before returning. Tearing them down while the device is still alive is therefore safe. Reproduced on User-Mode Linux with CONFIG_KASAN and CONFIG_VIRTIO_DEBUG by unbinding a virtio-uml device: BUG: KASAN: slab-use-after-free in virtio_debug_device_exit+0x36/0x4d Read of size 8 at addr 00000000616e0b10 by task init/1 __asan_report_load8_noabort virtio_debug_device_exit+0x36/0x4d unregister_virtio_device+0x48/0x75 virtio_uml_remove platform_remove device_release_driver_internal unbind_store Freed by task 1: kfree virtio_uml_release_dev device_release kobject_put put_device device_unregister With this applied, the report is gone and unbind is clean. Fixes: 96a8326d69ff ("virtio: add debugfs infrastructure to allow to debug virtio features") Assisted-by: Claude:claude-opus-5 Signed-off-by: Karl Mehltretter Signed-off-by: Michael S. Tsirkin Message-ID: <20260821213953.76906-1-kmehltretter@gmail.com>

virtio_ring: fix stale descriptor flags after a failed packed add

2026-09-07T22:54:02+00:00

In a packed ring the AVAIL and USED bits sit in the descriptor itself, so writing them makes that descriptor available. Those bit combinations flip meaning on every round of the ring, tracked by a wrap counter, so invalidating or validating a descriptor means inverting both bits. Commit 1ce9e6055fa0 ("virtio_ring: introduce packed ring support") has virtqueue_add_packed() make every descriptor of a chain available as it maps the chain, and write the head last. The device consumes the ring in order and stops at a head that is not available yet, so it never reaches the rest. When vring_map_one_sg() fails partway, unmap_release unmaps the segments and restores avail_used_flags, but the descriptors it wrote to in the ring stay marked with AVAIL and USED bits. The head is now the only entry that keeps the device from consuming these stale entries. For example, the ring would look like this now. Z - pre-previous command A - previous command B - aborted command C - current command [A1 DONE] [A2 DONE] [B2] [B3] [Z1 DONE] When the driver now attempts to issue the C command, the next add starts at the same head as B. If C spans less descriptors than B, there is no end marker because AVAIL and USED bits were still in place. And that means the device will start interpreting these stale entries (B2/B3) as another command entry, which then blocks the queue. This effect typically happens in swiotlb configurations under memory pressure, because vring_map_one_sg() can then fail with larger I/O requests which then leads to command abortions. There are broadly 2 ways to avoid leaving those flags behind: 1) Defer those flags too until the chain is complete. 2) Rewrite those flags for the previous wrap counter. Implement the second option in both packed add paths. The first option traverses the chain a second time on every successful add. The second option invalidates all added descriptors when any add fails. With this patch applied, a packed virtqueue keeps completing requests after a failed add. Fixes: 1ce9e6055fa0 ("virtio_ring: introduce packed ring support") Fixes: f6a15d854986 ("virtio_ring: add in order support") Assisted-by: Kiro:claude-opus-5 checkpatch sparse Signed-off-by: Alexander Graf Signed-off-by: Michael S. Tsirkin Message-ID: <20260817223229.28954-1-graf@amazon.com>

virtio_ring: fix infinite loop in virtnet_poll_cleantx when device is broken

2026-08-19T10:38:47+00:00

virtnet_poll_cleantx() contains a do-while loop that cleans up transmitted TX buffers and calls virtqueue_enable_cb_delayed() to check whether more buffers need processing. When the virtio backend stops responding during guest reboot, used->idx is never updated, so virtqueue_enable_cb_delayed() always returns false and the loop never terminates. Then it will block reboot process, and the guest will hang. The problem occurs during guest reboot under network traffic: 1. kernel_restart() -> device_shutdown() traverses the device list 2. virtio_dev_shutdown() calls virtio_break_device() which sets vq->broken = true 3. virtio_dev_shutdown() then calls virtio_synchronize_cbs() to wait for in-flight callbacks to complete 4. A virtio interrupt fires, softirq is deferred to ksoftirqd which calls net_rx_action() -> virtnet_poll() -> virtnet_poll_cleantx() 5. virtnet_poll_cleantx() enters the do-while loop and never exits because the QEMU backend has stopped updating used->idx, despite vq->broken having been set to true in step 2. Since the loop runs inside ksoftirqd (a SCHED_OTHER kthread), it is visible to the scheduler and does not trigger a hard lockup. However, the kthread never leaves the loop, so RCU detects it as a CPU stall and reports it periodically. Meanwhile, the reboot process remains blocked in device_shutdown() because virtio_dev_shutdown() cannot complete its synchronization step, and the guest hangs permanently. This can be reproduced on a guest with a virtio-net device: run iperf3 traffic in the guest, then trigger reboot. The reboot occasionally hangs permanently with RCU stall on ksoftirqd. Observed on ARM64 KVM guest: CPU#1 RCU stall (ksoftirqd/1), repeated periodically: virtqueue_enable_cb_delayed_split <- virtnet_poll <- __napi_poll <- net_rx_action <- handle_softirqs <- run_ksoftirqd <- smpboot_thread_fn <- kthread Fix by adding a vq->broken check in virtqueue_enable_cb_delayed(), so that the loop exits immediately when the device is broken, allowing the device shutdown to proceed. Signed-off-by: Jinqian Yang Reviewed-by: Xuan Zhuo Signed-off-by: Michael S. Tsirkin Message-ID: <20260716115940.394832-1-yangjinqian1@huawei.com>

virtio_mem: fix typo in comment

2026-08-19T10:38:47+00:00

Correct "actipn" to "action". Signed-off-by: xiongweimin Reviewed-by: Parav Pandit Acked-by: David Hildenbrand (Arm) Signed-off-by: Michael S. Tsirkin Message-ID: <20260714032417.201353-1-xiongwm2026@163.com>

virtio: fix article before virtio in dma-buf comment

2026-08-19T10:38:47+00:00

Use "a virtio" rather than "an virtio". Signed-off-by: xiongweimin Signed-off-by: Michael S. Tsirkin Message-ID: <20260714024513.188571-1-15927021679@163.com>