In the Linux kernel, the following vulnerability has been resolved:
scsi: mvsas: Fix use-after-free bugs in mvs_work_queue
During the detaching of Marvell's SAS/SATA controller, the original code calls cancel_delayed_work() in mvs_free() to cancel the delayed work item mwq->work_q. However, if mwq->work_q is already running, the cancel_delayed_work() may fail to cancel it. This can lead to use-after-free scenarios where mvs_free() frees the mvs_info while mvs_work_queue() is still executing and attempts to access the already-freed mvs_info.
A typical race condition is illustrated below:
CPU 0 (remove) | CPU 1 (delayed work callback) mvs_pci_remove() | mvs_free() | mvs_work_queue() cancel_delayed_work() | kfree(mvi) | | mvi-> // UAF
Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure that the delayed work item is properly canceled and any executing delayed work item completes before the mvs_info is deallocated.
This bug was found by static analysis.