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[174.165.208.10]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2a2f3c66bd3sm26625355ad.1.2025.12.19.08.08.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 Dec 2025 08:08:40 -0800 (PST) From: mhkelley58@gmail.com X-Google-Original-From: mhklinux@outlook.com To: haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, kys@microsoft.com, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, dan.carpenter@linaro.org Subject: [PATCH 1/1] Drivers: hv: Fix uninit'ed variable in hv_msg_dump() if CONFIG_PRINTK not set Date: Fri, 19 Dec 2025 08:08:32 -0800 Message-Id: <20251219160832.1628-1-mhklinux@outlook.com> X-Mailer: git-send-email 2.25.1 Reply-To: mhklinux@outlook.com Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Michael Kelley When CONFIG_PRINTK is not set, kmsg_dump_get_buffer() returns 'false' without setting the bytes_written argument. In such case, bytes_written is uninitialized when it is tested for zero. This is admittedly an unlikely scenario, but in the interest of correctness and avoiding tool noise about uninitialized variables, fix this by testing the return value before testing bytes_written. Fixes: 9c318a1d9b50 ("Drivers: hv: move panic report code from vmbus to hv early init code") Reported-by: kernel test robot Reported-by: Dan Carpenter Closes: https://lore.kernel.org/all/202512172102.OcUspn1Z-lkp@intel.com/ Signed-off-by: Michael Kelley --- drivers/hv/hv_common.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index f466a6099eff..de9e069c5a0c 100644 --- a/drivers/hv/hv_common.c +++ b/drivers/hv/hv_common.c @@ -188,6 +188,7 @@ static void hv_kmsg_dump(struct kmsg_dumper *dumper, { struct kmsg_dump_iter iter; size_t bytes_written; + bool ret; /* We are only interested in panics. */ if (detail->reason != KMSG_DUMP_PANIC || !sysctl_record_panic_msg) @@ -198,9 +199,9 @@ static void hv_kmsg_dump(struct kmsg_dumper *dumper, * be single-threaded. */ kmsg_dump_rewind(&iter); - kmsg_dump_get_buffer(&iter, false, hv_panic_page, HV_HYP_PAGE_SIZE, - &bytes_written); - if (!bytes_written) + ret = kmsg_dump_get_buffer(&iter, false, hv_panic_page, HV_HYP_PAGE_SIZE, + &bytes_written); + if (!ret || !bytes_written) return; /* * P3 to contain the physical address of the panic page & P4 to -- 2.25.1