CVE-2026-53274

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> net/smc: fix sleep-inside-lock in __smc_setsockopt() causing local DoS<br /> <br /> A logic flaw in __smc_setsockopt() allows a local unprivileged user to<br /> cause a Denial of Service (DoS) by holding the socket lock indefinitely.<br /> <br /> The function __smc_setsockopt() calls copy_from_sockptr() while holding<br /> lock_sock(sk). By passing a userfaultfd-monitored memory page (or<br /> FUSE-backed memory on systems where unprivileged userfaultfd is disabled)<br /> as the optval, an attacker can halt execution during the copy operation,<br /> keeping the lock held.<br /> <br /> Combined with asynchronous tear-down operations like shutdown(), this<br /> exhausts the kernel wq (kworkers) and triggers the hung task watchdog.<br /> <br /> [ 240.123456] INFO: task kworker/u8:2 blocked for more than 120 seconds.<br /> [ 240.123489] Call Trace:<br /> [ 240.123501] smc_shutdown+...<br /> [ 240.123512] lock_sock_nested+...<br /> <br /> This patch moves the user-space copy outside the lock_sock() critical<br /> section to prevent the issue.