From 5caae1deee89a6582c761d5dcd4b924b744426cc Mon Sep 17 00:00:00 2001 From: Mark Harris Date: Mon, 13 Jul 2026 17:30:56 -0700 Subject: [PATCH] riscv: hwprobe: Avoid uninitialized read in hwprobe_get_cpus() When cpusetsize < cpumask_size(), hwprobe_get_cpus() did not fully initialize its copy of the cpu mask, which could cause non-deterministic results from the riscv_hwprobe syscall on a system with more than 8 CPUs when the supplied cpu mask is empty. Address this by fully initializing the cpu mask. Fixes: e178bf146e4b ("RISC-V: hwprobe: Introduce which-cpus flag") Signed-off-by: Mark Harris Reviewed-by: Nam Cao Reviewed-by: Michael Ellerman Link: https://patch.msgid.link/20260714003056.73707-1-mark.hsj@gmail.com Signed-off-by: Paul Walmsley --- arch/riscv/kernel/sys_hwprobe.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c index 1659d31fd288..caf6762427c8 100644 --- a/arch/riscv/kernel/sys_hwprobe.c +++ b/arch/riscv/kernel/sys_hwprobe.c @@ -450,6 +450,7 @@ static int hwprobe_get_cpus(struct riscv_hwprobe __user *pairs, if (cpusetsize > cpumask_size()) cpusetsize = cpumask_size(); + cpumask_clear(&cpus); ret = copy_from_user(&cpus, cpus_user, cpusetsize); if (ret) return -EFAULT;