CVE-2025-39871

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> dmaengine: idxd: Remove improper idxd_free<br /> <br /> The call to idxd_free() introduces a duplicate put_device() leading to a<br /> reference count underflow:<br /> refcount_t: underflow; use-after-free.<br /> WARNING: CPU: 15 PID: 4428 at lib/refcount.c:28 refcount_warn_saturate+0xbe/0x110<br /> ...<br /> Call Trace:<br /> <br /> idxd_remove+0xe4/0x120 [idxd]<br /> pci_device_remove+0x3f/0xb0<br /> device_release_driver_internal+0x197/0x200<br /> driver_detach+0x48/0x90<br /> bus_remove_driver+0x74/0xf0<br /> pci_unregister_driver+0x2e/0xb0<br /> idxd_exit_module+0x34/0x7a0 [idxd]<br /> __do_sys_delete_module.constprop.0+0x183/0x280<br /> do_syscall_64+0x54/0xd70<br /> entry_SYSCALL_64_after_hwframe+0x76/0x7e<br /> <br /> The idxd_unregister_devices() which is invoked at the very beginning of<br /> idxd_remove(), already takes care of the necessary put_device() through the<br /> following call path:<br /> idxd_unregister_devices() -&gt; device_unregister() -&gt; put_device()<br /> <br /> In addition, when CONFIG_DEBUG_KOBJECT_RELEASE is enabled, put_device() may<br /> trigger asynchronous cleanup via schedule_delayed_work(). If idxd_free() is<br /> called immediately after, it can result in a use-after-free.<br /> <br /> Remove the improper idxd_free() to avoid both the refcount underflow and<br /> potential memory corruption during module unload.