kernel: io_uring/eventfd: ensure io_eventfd_signal() defers another RCU period

In the Linux kernel, the following vulnerability has been resolved: iouring/eventfd: ensure ioeventfdsignal defers another RCU period ioeventfddosignal is invoked from an RCU callback, but when dropping the reference to the ioevfd, it calls ioeventfdfree directly if the refcount drops to zero. Th...

DEBIAN-CVE-2025-21655

In the Linux kernel, the following vulnerability has been resolved: iouring/eventfd: ensure ioeventfdsignal defers another RCU period ioeventfddosignal is invoked from an RCU callback, but when dropping the reference to the ioevfd, it calls ioeventfdfree directly if the refcount drops to zero. Th...

CVE-2025-21655

CVE-2025-21655 in the Linux kernel’s io_uring/eventfd was fixed by deferring the freeing of the io_eventfd object to an additional RCU grace period. The issue arose because io_eventfd_do_signal() is called from an RCU callback and, when the reference to the io_ev_fd drops to zero, the code attemp...