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Mon, 13 Jul 2026 17:38:21 -0700 (PDT) Sender: Mark Harris From: Mark Harris To: Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: Alexandre Ghiti , Mark Harris , Nam Cao , Michael Ellerman , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] riscv: hwprobe: Avoid uninitialized read in hwprobe_get_cpus() Date: Mon, 13 Jul 2026 17:30:56 -0700 Message-ID: <20260714003056.73707-1-mark.hsj@gmail.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- v2: Add Fixes: and Reviewed-by: tags 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; -- 2.55.0 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 44E2DC44501 for ; 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Mon, 13 Jul 2026 17:38:22 -0700 (PDT) Received: from kira.gmail.com ([2601:646:9e01:94:5407:619f:bb42:316d]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-311747f72a6sm87768917eec.1.2026.07.13.17.38.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Jul 2026 17:38:21 -0700 (PDT) From: Mark Harris To: Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: Alexandre Ghiti , Mark Harris , Nam Cao , Michael Ellerman , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] riscv: hwprobe: Avoid uninitialized read in hwprobe_get_cpus() Date: Mon, 13 Jul 2026 17:30:56 -0700 Message-ID: <20260714003056.73707-1-mark.hsj@gmail.com> X-Mailer: git-send-email 2.55.0 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260713_173824_264680_F8C20397 X-CRM114-Status: UNSURE ( 8.49 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org 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 --- v2: Add Fixes: and Reviewed-by: tags 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; -- 2.55.0 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv