CVE-2025-21850

In the Linux kernel, in the xhci: dbgtty driver, if tty_register_driver() fails, it drops the reference but fails to set the global dbc_tty_driver to NULL, causing the unregister to be called again when the module exits. This leads to a use-after-free condition.

In the Linux kernel, in the crypto: qcom-rng module, the random number generator does not allow zero as an output, making its output distinguishable from truly random. Zero is a valid random number and should be allowed.

In the Linux kernel, in io_uring, eventfd signaling is done inline when adding the first entry to the work list, which can cause issues when the addition is done from a wakeup handler context. The fix adds the IOU_F_TWQ_IN_WAKE flag to force deferral of signaling via call_rcu_hurry() instead of inline signaling.

In the Linux kernel, a vulnerability was found in the amdgpu driver where amdgpu_devcoredump_format() recursively acquires a ww_mutex lock. This can lead to a deadlock when dumping IB contents from a hung job. The fix moves the operation to a separate helper using a single drm_exec context.

In the Linux kernel, in HID: core, there is a number/pointer type confusion on long items. When fetch_item() is called by hid_scan_report() on an item with HID_ITEM_TAG_LONG, it stores a pointer to the item data in item->data.longdata instead of storing a value directly. Functions item_udata() and item_sdata() incorrectly assume short format, leading to the lower part of a kernel pointer being printed as a number in dmesg.

A vulnerability in the Linux kernel causes a NULL pointer dereference in the PCI host-generic driver on 32-bit systems using CAM mode. During PCI bus enumeration, the first config read uses an uninitialized mapping, leading to a kernel panic. The issue stems from missing add_bus/remove_bus callbacks in the CAM operations, which are necessary for proper mapping of the config space.

A vulnerability in the Linux kernel's KCOV mechanism causes data corruption and race conditions on PREEMPT_RT systems. The issue stems from storing temporary KCOV state in per-CPU areas, which can be overwritten by nested softirq preemption. Additionally, under certain initialization conditions, it may lead to kernel panic or memory leaks.

In the Linux kernel, the drm/xe driver's DPT allocation paths were fixed. The fallback from VRAM to system memory was removed as it did not work and caused black screen with pipe faults. Also, stolen memory usage is avoided due to latency and risk of random system hangs under load.

In the Linux kernel, a vulnerability in the msm serial driver was fixed by disabling DMA for the console UART. Concurrent writes from userspace and the kernel can trigger a race condition resulting in an infinite loop of the same messages. The fix disables DMA for the console UART to ensure a reliable output path.

In the Linux kernel, a fix was made for an uncancelled rxrpc OOB message handler in AFS. The fix cancels OOB message processing (typically to respond to security challenges) and moves it to afs_wq so it is also waited for. The OOB handler now returns if the net namespace is no longer live.